This document summarizes research on the synthesis and characterization of group 4 metal complexes containing fluorinated bis(amidinate) ligands and their use as catalysts for polypropylene formation. Titanium and zirconium complexes containing various fluorinated bis(amidinate) ligands were synthesized and characterized using X-ray crystallography. The complexes were then tested as catalysts for propylene polymerization, producing high molecular weight atactic polypropylenes consistent with elastomeric polymers.
This document summarizes research on the synthesis and reactivity of group 4 metal complexes containing symmetric amidinate ligands. Various amidinate ligands were prepared by modifying substituents on the nitrogen atoms to tune steric properties. Titanium and hafnium amidinate dimethylamido and chloride complexes were synthesized and their solid-state and solution structures were studied. These complexes were tested as catalysts for the polymerization of propylene and ethylene after activation with MAO. The activity of the catalyst and properties of the polymers produced depended on the substituents of the amidine ligands. Further experiments provided insights into the mechanism of ethylene polymerization, identifying catalytic species using ESR, C60 radical trapping
This document summarizes a study on new titanium bis(amidinate) complexes containing electron-donating pendant arms that are used as catalysts for the stereospecific polymerization of propylene. The complexes were synthesized with different pendant arms including pyridine, dimethylamine, and furyl groups. When activated with methylalumoxane (MAO) or other cocatalysts, the complexes produced mixtures of isotactic and atactic polypropylene. The stereoregularity and yield of the polymers depended on the pendant arm and cocatalyst used. Unexpectedly, the isotactic polymers formed via a chain-end control mechanism rather than the typical insertion mechanism.
Studies of transition metal ion - 5- Sulphosalicylic acid doped PolyanilinesIOSR Journals
This document summarizes a study on transition metal ion-5-sulphosalicylic acid complexes used as dopants for polyaniline. Polyaniline was doped with various transition metal carbonates both with and without 5-sulphosalicylic acid. The doped polyanilines were characterized through various tests. Conductivity was found to increase with increasing acid concentration in the doping solution. Magnetic susceptibility measurements showed paramagnetic behavior for transition metal-doped polyanilines and diamagnetic behavior for polyaniline doped with only 5-sulphosalicylic acid. The polymers were found to be amorphous by XRD. SEM showed small
1. The document discusses different types of complexes that can form between molecules, including metal ion complexes, organic molecular complexes, and inclusion complexes.
2. Metal ion complexes involve donation of electron pairs from ligands to a central metal ion. Important types include inorganic complexes containing ligands like ammonia, and chelate complexes where a ligand donates multiple electron pairs.
3. Organic molecular complexes are weaker and involve polarization of molecules and charge transfer rather than covalent bonding. Examples discussed include complexes of drugs containing N-C=S moieties that can complex with iodine.
1. Complex compounds are molecules where some bonds cannot be described by classical theories of valency and involve anomalous bonds.
2. Complexes form through interactions like coordination bonds, hydrogen bonds, and van der Waals forces between different chemical species.
3. Complexation can alter properties like solubility, conductivity, and chemical reactivity and is used in applications like increasing drug solubility, purification of water, drug analysis, and as anticoagulants.
The document discusses unexpected results from treating MgCl2-supported polypropylene catalysts containing organometallic complexes with additional TiCl4. Adding TiCl4 at a level equal to the existing Ti increased catalyst activity by 70-95% and decreased the polymer melt flow rate by 50%, suggesting a two-component catalyst system. The author proposes the TiCl4 treatment replaces the organometallic complex and frees it to take an external role while restoring the original MgCl2/TiCl4 catalyst. This two-component system provides roughly equal contributions to activity from each component but differing effects on polymer properties like extractables. The author also suggests these complexes could be converted to single-site catalysts using reactive
This chapter discusses complexation and protein binding in pharmaceuticals. It defines the three classes of complexes as metal ion complexes, organic molecular complexes, and inclusion compounds. It describes the types of interactions that form complexes, such as coordination bonds and van der Waals forces. Metal complexes are discussed in depth, including examples of inorganic complexes like hexamminecobalt(III) chloride and the hybridization of metal orbitals. Chelates are described as complexes where ligands are attached to the same metal ion, conferring properties like chirality. Protein binding can influence drug action and is determined using methods like equilibrium dialysis.
The document discusses complexation and protein binding. It defines complexation as the process of combining individual atom groups, ions or molecules to create large ions or molecules. There are various types of complexes that are formed through different interactions. Applications of complexation include improving solubility, stability, and bioavailability of drugs. Methods for determining the stoichiometry of complexes include Job's method, mole ratio method, and slope ratio method which involve measuring a property of complexes formed at different concentration ratios. Protein binding is also discussed in relation to complexation and drug action.
This document summarizes research on the synthesis and reactivity of group 4 metal complexes containing symmetric amidinate ligands. Various amidinate ligands were prepared by modifying substituents on the nitrogen atoms to tune steric properties. Titanium and hafnium amidinate dimethylamido and chloride complexes were synthesized and their solid-state and solution structures were studied. These complexes were tested as catalysts for the polymerization of propylene and ethylene after activation with MAO. The activity of the catalyst and properties of the polymers produced depended on the substituents of the amidine ligands. Further experiments provided insights into the mechanism of ethylene polymerization, identifying catalytic species using ESR, C60 radical trapping
This document summarizes a study on new titanium bis(amidinate) complexes containing electron-donating pendant arms that are used as catalysts for the stereospecific polymerization of propylene. The complexes were synthesized with different pendant arms including pyridine, dimethylamine, and furyl groups. When activated with methylalumoxane (MAO) or other cocatalysts, the complexes produced mixtures of isotactic and atactic polypropylene. The stereoregularity and yield of the polymers depended on the pendant arm and cocatalyst used. Unexpectedly, the isotactic polymers formed via a chain-end control mechanism rather than the typical insertion mechanism.
Studies of transition metal ion - 5- Sulphosalicylic acid doped PolyanilinesIOSR Journals
This document summarizes a study on transition metal ion-5-sulphosalicylic acid complexes used as dopants for polyaniline. Polyaniline was doped with various transition metal carbonates both with and without 5-sulphosalicylic acid. The doped polyanilines were characterized through various tests. Conductivity was found to increase with increasing acid concentration in the doping solution. Magnetic susceptibility measurements showed paramagnetic behavior for transition metal-doped polyanilines and diamagnetic behavior for polyaniline doped with only 5-sulphosalicylic acid. The polymers were found to be amorphous by XRD. SEM showed small
1. The document discusses different types of complexes that can form between molecules, including metal ion complexes, organic molecular complexes, and inclusion complexes.
2. Metal ion complexes involve donation of electron pairs from ligands to a central metal ion. Important types include inorganic complexes containing ligands like ammonia, and chelate complexes where a ligand donates multiple electron pairs.
3. Organic molecular complexes are weaker and involve polarization of molecules and charge transfer rather than covalent bonding. Examples discussed include complexes of drugs containing N-C=S moieties that can complex with iodine.
1. Complex compounds are molecules where some bonds cannot be described by classical theories of valency and involve anomalous bonds.
2. Complexes form through interactions like coordination bonds, hydrogen bonds, and van der Waals forces between different chemical species.
3. Complexation can alter properties like solubility, conductivity, and chemical reactivity and is used in applications like increasing drug solubility, purification of water, drug analysis, and as anticoagulants.
The document discusses unexpected results from treating MgCl2-supported polypropylene catalysts containing organometallic complexes with additional TiCl4. Adding TiCl4 at a level equal to the existing Ti increased catalyst activity by 70-95% and decreased the polymer melt flow rate by 50%, suggesting a two-component catalyst system. The author proposes the TiCl4 treatment replaces the organometallic complex and frees it to take an external role while restoring the original MgCl2/TiCl4 catalyst. This two-component system provides roughly equal contributions to activity from each component but differing effects on polymer properties like extractables. The author also suggests these complexes could be converted to single-site catalysts using reactive
This chapter discusses complexation and protein binding in pharmaceuticals. It defines the three classes of complexes as metal ion complexes, organic molecular complexes, and inclusion compounds. It describes the types of interactions that form complexes, such as coordination bonds and van der Waals forces. Metal complexes are discussed in depth, including examples of inorganic complexes like hexamminecobalt(III) chloride and the hybridization of metal orbitals. Chelates are described as complexes where ligands are attached to the same metal ion, conferring properties like chirality. Protein binding can influence drug action and is determined using methods like equilibrium dialysis.
The document discusses complexation and protein binding. It defines complexation as the process of combining individual atom groups, ions or molecules to create large ions or molecules. There are various types of complexes that are formed through different interactions. Applications of complexation include improving solubility, stability, and bioavailability of drugs. Methods for determining the stoichiometry of complexes include Job's method, mole ratio method, and slope ratio method which involve measuring a property of complexes formed at different concentration ratios. Protein binding is also discussed in relation to complexation and drug action.
The document discusses retrosynthetic analysis, which is a problem-solving technique used in organic synthesis. It involves working backwards from the target molecule and breaking it down into simpler structures through the reverse of known reactions. This allows chemists to plan a synthesis by tracing the target back to commercially available starting materials. The document outlines common disconnections, reactions, and strategies used in retrosynthetic analysis and organic synthesis planning.
This document provides definitions and classifications of complex compounds. It defines complexes as molecules where most bonding structures can be described by classical theories but one or more bonds are anomalous. Complexes result from donor-acceptor reactions between Lewis acids and bases. They are divided into metal ion complexes, organic molecular complexes, and inclusion complexes. Metal complexes involve coordination between metal ions and ligands. Chelates form cyclic structures with multidentate ligands. Organic complexes involve weaker interactions like hydrogen bonding. Inclusion complexes entrap guest molecules in host structures like channels, layers, or cavities. Common examples of complexes and their properties are discussed.
Organocatalysis uses small organic molecules rather than metals to catalyze chemical reactions. Thiourea organocatalysis specifically uses thiourea derivatives to accelerate reactions through hydrogen bonding interactions. Primary amine thiourea catalysts have many advantages including being inexpensive, non-toxic, stable, and able to catalyze reactions with high enantioselectivity. The document provides procedures for synthesizing a primary amine thiourea catalyst through Boc protection of an amino acid, formation of an amide bond with benzyl amine, Boc deprotection, and conversion to an isothiocyanate derivative.
This document summarizes information about several antifungal drugs, including their molecular formulas, properties, synthesis methods, and uses. It discusses Ketoconazole, Terconazole, Metronidazole, and Miconazole. For each drug, it provides the molecular formula, describes the synthesis starting from various reactants and reaction steps, and lists clinical uses such as treating fungal infections, jock itch, and vaginal thrush. The document aims to provide information on the preparation and applications of important antifungal heterocyclic compounds.
The document discusses the Ziegler-Natta catalyst, which is an important class of chemical compounds that can polymerize olefins like ethylene and propylene into high molecular weight polymers with stereoregular structures. It describes how Karl Zeigler developed catalysts in 1953 that produced polyethylene with high molecular weight and Natta further developed the methodology in 1954. Zeigler and Natta were jointly awarded the Nobel Prize in 1963. The mechanism of the Ziegler-Natta catalyst involves the formation of a complex between titanium and aluminum that allows for the insertion of monomer units between titanium and an ethyl group to stereospecifically form isotactic polymers.
Applications of furan and its derivativeAAMIR NURLE
1) Furan and its derivatives have various applications including use as intermediates for dyes, pigments, brighteners, and specialty chemicals. 2,5-bis(para-amino phenyl) furan and its sulfonated derivatives specifically can be used as brighteners or intermediates for additional dyes and pigments. 2) Diaryl furan compounds containing groups like hydroxyl, carbonyl, or halogen that are ortho to amino groups are important for producing metal-complex dyes with improved light fastness. 3) Furan and related compounds like furfural and furfuryl alcohol also have applications as solvents, fuel additives, and in resins, adhesives,
This document discusses the polymerization of norbornene monomers. It begins with an introduction to polyolefins and focuses on norbornene. It then discusses the three main mechanisms for norbornene polymerization: ring opening metathesis polymerization, cationic polymerization, and addition or vinyl polymerization. The document focuses on addition polymerization using nickel-based catalysts. It provides data from various studies on the effects of catalyst type, ligand structure, aluminum-to-nickel ratio, temperature, and other reaction conditions on polymerization activity, molecular weight, and properties. Tables and figures show results from specific nickel catalyst systems. References are provided for further background reading.
This document provides an overview of the heterocyclic compound pyrrole. Pyrrole is a five-membered heterocyclic compound containing one nitrogen atom. It plays an important role in living organisms as the structural feature of chlorophyll and heme contains four linked pyrrole rings. Pyrrole has weak acidic properties similar to acetylene. It can be synthesized through various methods including the reaction of acetylene and ammonia at high temperatures. Pyrrole undergoes characteristic reactions like oxidation, reduction, alkylation and acylation. It is involved in the synthesis of important drugs like Obatoclax which is used to treat various cancers.
Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments
This document provides a summary of organocatalysis and its use in the enantioselective synthesis of fine chemicals. Organocatalysis refers to the use of small organic molecules to catalyze organic transformations. There are two main types of organocatalysis - covalent organocatalysis where the catalyst forms a covalent bond with the substrate, and non-covalent organocatalysis involving hydrogen bonding or ion pair formation. Examples of successful organocatalytic reactions discussed include the proline-catalyzed aldol reaction and the synthesis of oseltamivir using enamine catalysis. The field
This document discusses ionic chain polymerization, specifically cationic polymerization. It begins by introducing cationic initiators such as Lewis acids and protonic acids. Cationic polymerization proceeds via a chain mechanism involving initiation, propagation, and termination steps. The carbocation intermediate is stabilized by electron-donating substituents on the monomer. Common industrial cationic polymerizations include isobutylene and styrene. Factors that influence the rate of cationic polymerization such as solvent effects and carbocation stability are also discussed.
This document provides an overview of heterocyclic compounds, including azoles, azines, and their properties. It discusses key heterocyclic compounds like oxazole, thiazole, pyrazole, pyridazine, pyrimidine, and pyrazine. For each compound, it describes their synthetic methods, physical properties like state, boiling point, odor, and solubility. It also outlines some of their chemical properties such as electrophilic substitution reactions and nucleophilic reactions. The document serves to introduce several important classes of heterocyclic compounds.
The document discusses several classes of heterocyclic compounds containing carbon and other heteroatoms like nitrogen, sulfur, and oxygen in their rings. It summarizes the key properties and stability of different ring structures like pyridine, imidazole, pyrimidine, purine, and others. Important derivatives and biological roles of these heterocycles are highlighted, including their roles in coenzymes, vitamins, nucleic acids, and other biomolecules.
The document discusses methodology in organic synthesis, including examples of natural products. It describes convergent and divergent synthesis strategies. Convergent synthesis involves coupling molecular fragments through independent synthesis to improve reaction yields compared to linear synthesis. Divergent synthesis starts from a central core and generates a library of compounds through successive additions. Functional group interconversion and addition techniques are discussed to allow for disconnection of target molecules during retrosynthetic analysis.
Synthesis, characterization, amdet and docking studies of novel diclofenac de...Alexander Decker
This document discusses the synthesis and characterization of novel diclofenac derivatives containing phenylalanine moieties as selective inhibitors of cyclooxygenase-2 (COX-2). Sixteen novel diclofenac derivatives were synthesized and their structures were confirmed through various analytical techniques. Molecular docking studies predicted that compounds 7, 12 and 16 showed stronger binding with COX-2 than the reference drug diclofenac, making them potential selective COX-2 inhibitors. The binding scores of these compounds were higher than diclofenac when docked into the active site of COX-2.
Study of the Synthesis of Pyrrole and its Derivativesijtsrd
The article presents the theoretical studies results of hydraulic shock with flow continuity rupture in the pressure the pumping station pipeline. Calculated dependencies are obtained for calculating the shock pressure magnitude and the first period duration of reduced pressure, taking into account the hydraulic resistance along the pipeline length in the discontinuity event in the flow. The calculation results are compared with the Professor D.N. Smirnov"-™s experiments results.Comparative calculations using the proposed method with D.N. Smirnov experimental data gives a satisfactory agreement and confirms the proposed method reliability. Safarov Megli Djumayevich | Nazarov Asror Allanazarovich "Study of the Synthesis of Pyrrole and its Derivatives" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Special Issue | Modern Trends in Scientific Research and Development, Case of Asia , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd37971.pdf Paper Url :https://www.ijtsrd.com/economics/other/37971/study-of-the-synthesis-of-pyrrole-and-its-derivatives/safarov-megli-djumayevich
This document summarizes research on the use of amidinate group 4 metal complexes as catalysts for olefin polymerization. Key points include:
- Bis(amidinate) zirconium and titanium complexes can polymerize ethylene and propylene into elastomeric polymers through an intramolecular epimerization mechanism.
- The symmetry of complexes containing one, two, or three amidinate ligands influences the stereochemistry of the resulting polypropylene, with C2 and C3 complexes producing isotactic and atactic polymers, respectively.
- The nature of the co-catalyst and reaction conditions, such as pressure, temperature and solvent, can alter the active catalytic species
Gonzalez et al., JACS 2011, 133, 5500-5507Vincent M
This document summarizes research on using phosphoramidite gold(I) catalysts to catalyze the diastereo- and enantioselective synthesis of 3,4-substituted pyrrolidines through cycloadditions of allenenes. Key findings include:
1) The phosphoramidite ligand (R,R,R)-9a enabled highly enantioselective cycloadditions, providing up to 99% ee for various allenenes.
2) Computational studies supported a stepwise mechanism involving carbocation intermediates that explain the regio- and stereoselectivity of the reactions.
3) Both cis and trans reaction pathways were found to be
The document summarizes research on polyaniline-polypyrrole/yttrium oxide (PANIPPy/Y2O3) nanocomposites. PANIPPy/Y2O3 composites were synthesized by in-situ polymerization of aniline and pyrrole with varying amounts of Y2O3. The composites were characterized using FTIR, XRD, SEM, TEM, thermal analysis, and electrical measurements. FTIR showed peaks indicating formation of the copolymer with some shifting due to Y2O3 addition. XRD showed an amorphous structure with some crystallinity increasing with higher Y2O3 content. SEM showed irregularly shaped agglomer
The document discusses retrosynthetic analysis, which is a problem-solving technique used in organic synthesis. It involves working backwards from the target molecule and breaking it down into simpler structures through the reverse of known reactions. This allows chemists to plan a synthesis by tracing the target back to commercially available starting materials. The document outlines common disconnections, reactions, and strategies used in retrosynthetic analysis and organic synthesis planning.
This document provides definitions and classifications of complex compounds. It defines complexes as molecules where most bonding structures can be described by classical theories but one or more bonds are anomalous. Complexes result from donor-acceptor reactions between Lewis acids and bases. They are divided into metal ion complexes, organic molecular complexes, and inclusion complexes. Metal complexes involve coordination between metal ions and ligands. Chelates form cyclic structures with multidentate ligands. Organic complexes involve weaker interactions like hydrogen bonding. Inclusion complexes entrap guest molecules in host structures like channels, layers, or cavities. Common examples of complexes and their properties are discussed.
Organocatalysis uses small organic molecules rather than metals to catalyze chemical reactions. Thiourea organocatalysis specifically uses thiourea derivatives to accelerate reactions through hydrogen bonding interactions. Primary amine thiourea catalysts have many advantages including being inexpensive, non-toxic, stable, and able to catalyze reactions with high enantioselectivity. The document provides procedures for synthesizing a primary amine thiourea catalyst through Boc protection of an amino acid, formation of an amide bond with benzyl amine, Boc deprotection, and conversion to an isothiocyanate derivative.
This document summarizes information about several antifungal drugs, including their molecular formulas, properties, synthesis methods, and uses. It discusses Ketoconazole, Terconazole, Metronidazole, and Miconazole. For each drug, it provides the molecular formula, describes the synthesis starting from various reactants and reaction steps, and lists clinical uses such as treating fungal infections, jock itch, and vaginal thrush. The document aims to provide information on the preparation and applications of important antifungal heterocyclic compounds.
The document discusses the Ziegler-Natta catalyst, which is an important class of chemical compounds that can polymerize olefins like ethylene and propylene into high molecular weight polymers with stereoregular structures. It describes how Karl Zeigler developed catalysts in 1953 that produced polyethylene with high molecular weight and Natta further developed the methodology in 1954. Zeigler and Natta were jointly awarded the Nobel Prize in 1963. The mechanism of the Ziegler-Natta catalyst involves the formation of a complex between titanium and aluminum that allows for the insertion of monomer units between titanium and an ethyl group to stereospecifically form isotactic polymers.
Applications of furan and its derivativeAAMIR NURLE
1) Furan and its derivatives have various applications including use as intermediates for dyes, pigments, brighteners, and specialty chemicals. 2,5-bis(para-amino phenyl) furan and its sulfonated derivatives specifically can be used as brighteners or intermediates for additional dyes and pigments. 2) Diaryl furan compounds containing groups like hydroxyl, carbonyl, or halogen that are ortho to amino groups are important for producing metal-complex dyes with improved light fastness. 3) Furan and related compounds like furfural and furfuryl alcohol also have applications as solvents, fuel additives, and in resins, adhesives,
This document discusses the polymerization of norbornene monomers. It begins with an introduction to polyolefins and focuses on norbornene. It then discusses the three main mechanisms for norbornene polymerization: ring opening metathesis polymerization, cationic polymerization, and addition or vinyl polymerization. The document focuses on addition polymerization using nickel-based catalysts. It provides data from various studies on the effects of catalyst type, ligand structure, aluminum-to-nickel ratio, temperature, and other reaction conditions on polymerization activity, molecular weight, and properties. Tables and figures show results from specific nickel catalyst systems. References are provided for further background reading.
This document provides an overview of the heterocyclic compound pyrrole. Pyrrole is a five-membered heterocyclic compound containing one nitrogen atom. It plays an important role in living organisms as the structural feature of chlorophyll and heme contains four linked pyrrole rings. Pyrrole has weak acidic properties similar to acetylene. It can be synthesized through various methods including the reaction of acetylene and ammonia at high temperatures. Pyrrole undergoes characteristic reactions like oxidation, reduction, alkylation and acylation. It is involved in the synthesis of important drugs like Obatoclax which is used to treat various cancers.
Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments
This document provides a summary of organocatalysis and its use in the enantioselective synthesis of fine chemicals. Organocatalysis refers to the use of small organic molecules to catalyze organic transformations. There are two main types of organocatalysis - covalent organocatalysis where the catalyst forms a covalent bond with the substrate, and non-covalent organocatalysis involving hydrogen bonding or ion pair formation. Examples of successful organocatalytic reactions discussed include the proline-catalyzed aldol reaction and the synthesis of oseltamivir using enamine catalysis. The field
This document discusses ionic chain polymerization, specifically cationic polymerization. It begins by introducing cationic initiators such as Lewis acids and protonic acids. Cationic polymerization proceeds via a chain mechanism involving initiation, propagation, and termination steps. The carbocation intermediate is stabilized by electron-donating substituents on the monomer. Common industrial cationic polymerizations include isobutylene and styrene. Factors that influence the rate of cationic polymerization such as solvent effects and carbocation stability are also discussed.
This document provides an overview of heterocyclic compounds, including azoles, azines, and their properties. It discusses key heterocyclic compounds like oxazole, thiazole, pyrazole, pyridazine, pyrimidine, and pyrazine. For each compound, it describes their synthetic methods, physical properties like state, boiling point, odor, and solubility. It also outlines some of their chemical properties such as electrophilic substitution reactions and nucleophilic reactions. The document serves to introduce several important classes of heterocyclic compounds.
The document discusses several classes of heterocyclic compounds containing carbon and other heteroatoms like nitrogen, sulfur, and oxygen in their rings. It summarizes the key properties and stability of different ring structures like pyridine, imidazole, pyrimidine, purine, and others. Important derivatives and biological roles of these heterocycles are highlighted, including their roles in coenzymes, vitamins, nucleic acids, and other biomolecules.
The document discusses methodology in organic synthesis, including examples of natural products. It describes convergent and divergent synthesis strategies. Convergent synthesis involves coupling molecular fragments through independent synthesis to improve reaction yields compared to linear synthesis. Divergent synthesis starts from a central core and generates a library of compounds through successive additions. Functional group interconversion and addition techniques are discussed to allow for disconnection of target molecules during retrosynthetic analysis.
Synthesis, characterization, amdet and docking studies of novel diclofenac de...Alexander Decker
This document discusses the synthesis and characterization of novel diclofenac derivatives containing phenylalanine moieties as selective inhibitors of cyclooxygenase-2 (COX-2). Sixteen novel diclofenac derivatives were synthesized and their structures were confirmed through various analytical techniques. Molecular docking studies predicted that compounds 7, 12 and 16 showed stronger binding with COX-2 than the reference drug diclofenac, making them potential selective COX-2 inhibitors. The binding scores of these compounds were higher than diclofenac when docked into the active site of COX-2.
Study of the Synthesis of Pyrrole and its Derivativesijtsrd
The article presents the theoretical studies results of hydraulic shock with flow continuity rupture in the pressure the pumping station pipeline. Calculated dependencies are obtained for calculating the shock pressure magnitude and the first period duration of reduced pressure, taking into account the hydraulic resistance along the pipeline length in the discontinuity event in the flow. The calculation results are compared with the Professor D.N. Smirnov"-™s experiments results.Comparative calculations using the proposed method with D.N. Smirnov experimental data gives a satisfactory agreement and confirms the proposed method reliability. Safarov Megli Djumayevich | Nazarov Asror Allanazarovich "Study of the Synthesis of Pyrrole and its Derivatives" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Special Issue | Modern Trends in Scientific Research and Development, Case of Asia , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd37971.pdf Paper Url :https://www.ijtsrd.com/economics/other/37971/study-of-the-synthesis-of-pyrrole-and-its-derivatives/safarov-megli-djumayevich
This document summarizes research on the use of amidinate group 4 metal complexes as catalysts for olefin polymerization. Key points include:
- Bis(amidinate) zirconium and titanium complexes can polymerize ethylene and propylene into elastomeric polymers through an intramolecular epimerization mechanism.
- The symmetry of complexes containing one, two, or three amidinate ligands influences the stereochemistry of the resulting polypropylene, with C2 and C3 complexes producing isotactic and atactic polymers, respectively.
- The nature of the co-catalyst and reaction conditions, such as pressure, temperature and solvent, can alter the active catalytic species
Gonzalez et al., JACS 2011, 133, 5500-5507Vincent M
This document summarizes research on using phosphoramidite gold(I) catalysts to catalyze the diastereo- and enantioselective synthesis of 3,4-substituted pyrrolidines through cycloadditions of allenenes. Key findings include:
1) The phosphoramidite ligand (R,R,R)-9a enabled highly enantioselective cycloadditions, providing up to 99% ee for various allenenes.
2) Computational studies supported a stepwise mechanism involving carbocation intermediates that explain the regio- and stereoselectivity of the reactions.
3) Both cis and trans reaction pathways were found to be
The document summarizes research on polyaniline-polypyrrole/yttrium oxide (PANIPPy/Y2O3) nanocomposites. PANIPPy/Y2O3 composites were synthesized by in-situ polymerization of aniline and pyrrole with varying amounts of Y2O3. The composites were characterized using FTIR, XRD, SEM, TEM, thermal analysis, and electrical measurements. FTIR showed peaks indicating formation of the copolymer with some shifting due to Y2O3 addition. XRD showed an amorphous structure with some crystallinity increasing with higher Y2O3 content. SEM showed irregularly shaped agglomer
This document summarizes the synthesis and characterization of a new thio-triazole ligand and its complexes with selected metals. A new ligand, thiocarboxyphenyl-4-allyl-5-phenyl-4H-1,2,4-triazole (L), was prepared and characterized using micro elemental analysis and infrared spectroscopy. This ligand was then reacted with Fe(III), Cu(II), Cd(II), Hg(II) and Au(III) to form new complexes. These complexes were identified through various techniques and their chemical formulas and geometries were suggested. The biological activity of the complexes against selected microorganisms was also examined.
1. Paracetamol is generally safe at recommended doses but can cause acute liver failure and require transplantation at higher overdose doses due to its intrinsic toxicity.
2. At therapeutic doses, paracetamol is mainly metabolized through non-toxic pathways like sulfation and glucuronidation. However, at overdose levels it is oxidized by cytochrome P450 2E1 to form the toxic metabolite NAPQI.
3. NAPQI is normally detoxified by conjugating with glutathione, but an overdose depletes glutathione reserves allowing NAPQI to accumulate and cause
Amino acids are organic compounds that serve as building blocks of proteins. There are 20 standard amino acids used in protein synthesis, but over 700 naturally occurring amino acids have been identified. Amino acids have unique chemical properties due to their acid-base behavior and side chain groups. They play important roles beyond protein synthesis, including as intermediates in metabolic pathways and performing cellular signaling functions. Their chirality gives rise to L and D stereoisomers, with L-amino acids comprising the building blocks of natural proteins.
The document summarizes the Chan-Lam coupling reaction, which is a copper-catalyzed coupling between an aryl boronic acid and an alcohol or amine to form secondary aryl ethers or aryl amines. It provides the history of the reaction and compares it to related palladium-catalyzed reactions. The document then discusses the proposed mechanism and provides several applications of the Chan-Lam coupling reaction in synthesizing drug molecules, heteroarenes, aminoesters, and other compounds. In conclusion, the author discusses developing an improved Chan-Lam protocol using a novel copper catalyst that is simple, rapid, and produces products at room temperature in a short time.
Synthesis and Studies of Some New Dioxouranium (VI) Complexes with Azoester L...IOSRJAC
A1004010111Some new complexes of uranyl (VI) metal ion with different anions (viz. Cl- ,I- ,NO- 3 and OAc- ) have been synthesized using azoester ligand. Complexes were characterized by traditional methods viz. melting point measurements, conductivity measurements. These were also characterized by modern spectral methods viz. IR including far IR, UV –vis. spectra. Thermal studies specially DTA studies of representative have also been done and reported. Some of the complexes were also screened against selected microbes to check their antimicrobial activities. Coordination number of these complexes are proposed to be 8, 10 and 12 and tentative structures of the complexes are also reported in the present paper.
This document summarizes research into the effects of methoxy-substituted metalloporphyrins as catalysts in the epoxidation of alkenes. Five different manganese tetraphenylporphyrin acetates were synthesized with varying numbers and positions of methoxy substituents on the phenyl rings. These porphyrins were then used as catalysts for the epoxidation of various alkenes using tetra-n-butylammonium hydrogen monopersulfate as the oxidant and imidazole as the axial ligand. The catalytic activity of the porphyrins followed the order: unmodified TPPMnOAc ≥ di-methoxy substituted T(2,3-
Isoquinoline is a heterocyclic aromatic organic compound that is a structural isomer of quinoline. It consists of a benzene ring fused to a pyridine ring. Isoquinoline derivatives have many pharmaceutical applications including use as antispasmodics, antitussives, anesthetics, and in the production of morphine and related alkaloids. Isoquinoline can be prepared through the Bischler-Napieralski synthesis which involves the condensation and rearrangement of 2-phenylethylamine or through the reaction of cinnamaldehyde with hydroxylamine. Isoquinoline undergoes electrophilic aromatic substitution, oxidation, and reduction reactions.
This document describes a computational study of the reactions of monomeric methyllithium with carbon monoxide (CO), methylisonitrile (CNMe), and acetonitrile (NCMe) using high-level ab initio calculations. The reactions of tetrameric and hexameric methyllithium with CO and CNMe are also discussed and compared to experimental results. Liquid xenon was used as the solvent to allow hexameric and tetrameric structures to exist and prevent disaggregation. The key findings from the computational study of monomeric methyllithium will provide insight into the fundamental behavior of lithium in a simpler system compared to previous studies of aggregated organolithium structures.
Spectral Studies of Some Transition Metal Ion complexes with 4-[(E)-(Ferrocen...IOSR Journals
Several new complexes of some transition metal ions with organometallic compounds were derived from ferrocencecarboxylaldehyde and 4-amino-2-hydroxy pyridine. These organometallic complexes were investigated by using some analytical techniques like infrared, mass spectra, electronic spectra, electron spin resonance, thermal analysis, magnetic moment, conductivity and antimicrobial activity. From the obtained elemental analysis data, organometallic compounds complexes shows 1:2 [M: L] ratio and general formula of the complex is [ML2.2H2O]. These complexes revealed a non-electrolytic nature. The magnetic moment values of the complexes exhibited the paramagnetic as well as diamagnetic in nature. The coordination behavior of the metal ions towards to the investigated organometallic compounds takes place through >C=N- and –OH groups. The electronic spectral data shows that all the complexes are covalent in nature, octahedral structure with co-ordination number six. Organometallic compound complexes were loses two water molecules subjected to simultaneous thermo gravimetric analysis, to study their decomposition mechanism and thermal stability. Mass spectra of the organometallic compound and their complexes are matched with theoretical values of the masses. The prepared organometallic compounds and their metal complexes were screened for their antibacterial activity against some bacterial species, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus Pyogones. The Antimicrobial activity data show the metal complexes to be more active than the parent organometallic compounds.
A TiO2 immobilized Ru(II) polyazine complex: a visible-light active photoredo...Pawan Kumar
This document describes the development of a TiO2 immobilized Ru(II) polyazine complex photocatalyst for the oxidative cyanation of tertiary amines to a-aminonitriles. Key points:
- The photocatalyst was synthesized by grafting a ruthenium polyazine complex onto nanocrystalline TiO2.
- Under visible light irradiation, the photocatalyst efficiently catalyzed the oxidative cyanation of various tertiary amines to the corresponding a-aminonitriles in high yields using molecular oxygen as the oxidant.
- The photocatalyst could be easily recovered by simple filtration and reused for several runs with consistent activity, demonstrating its recyclability.
Project_Ionic_Liquid_Master 1 of Chemistry and BiologyJing YI
This document summarizes the synthesis of new imidazolium salts intended for use as vectors for siRNA transfection. It describes the step-by-step synthesis of intermediates including 1-alkyl-3-[3,4-bis(dodecyloxy)benzyl]-4H-imidazolium chloride and its deprotected form. It also discusses the inhibition of lactoperoxidase-catalyzed oxidation by an imidazole-based thione synthesized from one of the intermediates. The synthesis routes achieved good yields for the intermediates and products, which were characterized by various analytical techniques. The document concludes by discussing the different potential applications of the synthesized compounds.
A [Fe(bpy)3]2+ grafted graphitic carbon nitride hybrid for visible light assi...Pawan Kumar
The present paper describes the use of a readily synthesized, environmentally benign, reusable and nontoxic
iron based nanocomposite i.e iron(II) bipyridine grafted to graphitic carbon nitride (Fe(bpy)3/npg-
C3N4) as a photocatalyst, molecular oxygen as an oxidant and a household white LED as a light emitting
source for the oxidative coupling of benzylamines under mild reaction conditions. The developed heterogenized
homogeneous photocatalyst showed excellent activity with the added benefits of facile recovery
and efficient recycling ability without any significant loss in catalytic activity.
A [Fe(bpy)3]2+ grafted graphitic carbon nitride hybrid for visible light assi...Pawan Kumar
The document summarizes the development of an iron(II) bipyridine complex grafted to nanoporous graphitic carbon nitride (Fe(bpy)3/npg-C3N4) as a photocatalyst for the oxidative coupling of benzylamines using molecular oxygen and visible light. The photocatalyst showed excellent activity and the benefits of easy recovery and recycling without loss of activity. Characterization methods like SEM, TEM, XRD and XPS confirmed the immobilization of the iron complex on the carbon nitride support without affecting its structure. The photocatalyst exhibited enhanced surface area and visible light absorption compared to the individual components. It represents an efficient and reusable system for the oxidative reaction under
Synthesis, Structures, and Catalytic Properties of Late-Transition-Metal 2,6-...mariam1020
The document summarizes research into synthesizing and characterizing complexes of the ligand 2,6-bis(2-phosphaethenyl)pyridine (PNP) with late transition metals. Rhodium, copper and silver complexes were prepared and analyzed. The PNP ligand coordinates in a tridentate fashion to rhodium and copper, but binds only through the two phosphorus atoms to silver. The rhodium complex was found to catalyze a conjugate addition reaction.
The document summarizes research into synthesizing and characterizing complexes of the ligand 2,6-bis(2-phosphaethenyl)pyridine (PNP) with late transition metals. Rhodium, copper and silver complexes were prepared and analyzed. The PNP ligand coordinates in a tridentate fashion to rhodium and copper, but binds only through the two phosphorus atoms to silver. The rhodium complex was found to catalyze a conjugate addition reaction.
This document discusses different types of metal ion complexes and protein binding. It describes inorganic complexes containing ligands such as ammonia and cyanide. Chelates form more stable complexes due to multiple bonding sites for the metal. Organic molecular complexes involve weaker interactions like hydrogen bonding or charge transfer. Inclusion complexes trap one component within the lattice structure of the other. Common examples discussed include hexamine cobalt chloride, caffeine complexes, and drug polymer interactions.
2. solution and solid-state structures, and their propylene
polymerization behavior.
■ RESULTS AND DISCUSSION
We start the presentation of the results by disclosing why the
specific ligands were designed for this study. We have recently
shown (Scheme 1)9
that in the cationic mono aryl/phenyl
amidinate complexes the aromatic ring will rearrange,
producing a κ6
coordination structure and any substituent at
the para position will interact with a growing polymer chain,
retarding a chain transfer and allowing higher molecular
weights (the bigger the substituent, the larger the molecular
weight of the obtained polymer). This is a steric effect of the
para substituent exhibiting a linear free energy relationship with
the Taft parameter. Hence, to eliminate any π bonding of the
aryl/phenyl amidinate ring while keeping the steric environ-
ment similar to that of the arylamidinates, the ligands were
prepared with an isopropyl moiety, instead of the aryl group, at
the amidine carbon substituent. In addition, a range of
differently fluorinated aromatic rings were used as the
amidinate nitrogen substituents. The amidines were synthesized
using polyphosphoric acid trimethylsilyl esters (PPSE) as the
condensation reagent (eq 1).13
Our first attempts to prepare the ligand containing the
pentafluorophenyl ring by the condensation of the aniline with
the corresponding acyl chloride and the concomitant
condensation of the resulting amide with an additional 1
equiv of pentafluoroaniline, led to very low yields (2−5%) of
the desired amidine 5. Full conversion toward the desired
amidine 5 (30% isolated yield) and the corresponding
imidazole 6 (70% isolated yield) were obtained (Scheme 2)
in the condensation of pentafluoroaniline with isobutyric acid,
in the presence of PPSE.13
Interestingly, we have found that the
order of addition of the reagents to the reaction mixture has a
dramatic influence on the obtained ratio for the two products. If
the pentafluoroaniline is added first to the PPSE, the imidazole
6 is the only observed product, isolated in 96% yield. However,
if the isobutyric acid is added first to the PPSE, followed by the
addition of the pentafluoroaniline, a mixture of the amidine 5
and the imidazole 6 is obtained. Addition of a slight excess of
isobutyric acid (beyond 1 equiv) results in the production of
the corresponding amide and the imidazole without formation
of the amidine. These results indicate that the amide can be
attacked by the amine either at the carbonyl group, affording
the amidine 5, or at the ortho position of the C6F5 ring,
removing a fluorine atom followed by an intramolecular ring
closure to form the imidazole 6. Interestingly, a mixture of the
amidine with PPSE does not produce imidazole.
Perspective views of the molecular structures of the amidines
3−5 and the corresponding imidazole 6 are presented in
Figures 1−4, respectively. Notably, the methyl groups of the
isopropyl moiety are disposed in the solid structure to minimize
interactions with any nearby fluorine atoms. In addition, the
isopropyl group forms a dihedral angle with the N−C−N plane,
C15−C14−C13−N2 = 57.79 and 50.28° and C16−C14−
C13−N2 = 68.34 and 72.84°, for ligand 5 and compound 6,
respectively, similarly to the arylamidinates (vide infra). As can
be observed for all the amidine ligands, the NH−C(central)
and the NC bond lengths and the NC−NH bond of all of
the amidine ligands are alike, exhibiting no major differences.
Several titanium and zirconium complexes were prepared by
the reaction of 1 equiv of either Ti(NMe2)4 or Zr(NMe2)4
metal precursor with 2 equiv of the corresponding neutral
amidines (eq 2). For the corresponding titanium complexes (7,
9, and 11) and the zirconium complex (12) X-ray crystallo-
Scheme 1. Active Species Formed during the Activation of Titanium Bis(p-arylamidinate) Dichloride Complex with MAO
Organometallics Article
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3. graphic studies were performed, and the Mercury diagrams are
presented in Figures 5−8, respectively.
In the solid state, complexes 7, 9, 11, and 12 all exhibit C2
symmetry, where the metal is situated in a pseudo-octahedral
environment that is formed by four nitrogen atoms from the
amidinate ligands and two nitrogen atoms from the
dimethylamido groups. In these complexes, the dimethylamido
groups are disposed in a cis position, and the M−N bond
lengths of the dimethylamido moieties (1.893(2) and 1.899(2)
Å for complex 7, 1.893(5) and 1.898(5) Å for complex 9, and
1.889(5) and 2.031(3) Å for complexes 11 and 12,
respectively) are shorter, as expected, than the M−N bond
lengths of the coordinated amidinate (2.1018(18), 2.1769(19),
2.091(2), and 2.222(2) Å for complex 7, 2.120(5), 2.214(5),
2.105(5), and 2.234(5) Å for complex 9, 2.124(6) and 2.247(5)
Å for complex 11, and 2.242(3) and 2.341(3) Å for complex
12, respectively). These latter M−N bond lengths are
comparable to those found in previously reported amidinate
complexes.14
Scheme 2. Synthesis of the Bis(pentafluorophenyl) Isopropyl Amidinate Ligand 5 and the Corresponding Benzimidazole 6
Figure 1. Mercury diagram of the molecular structure of amidine 3
and (25% probability ellipsoids). Hydrogen atoms are omitted for
clarity. Representative bond lengths (Å) and angles (deg): C(1)−
N(1) = 1.362(2); C(1)−N(2) = 1.287(2); C(11)−N(1) = 1.416(2);
C(5)−N(2) = 1.418(2); C(14)−F(2) = 1.366(3); C(8)−F(1) =
1.360(2); N(2)−C(1)−N(1) = 119.85(16).
Figure 2. Mercury diagram of the molecular structure of amidine 4
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): C(11)−N(1) =
1.374(4); C(11)−N(2) = 1.268(4); C(9)−N(1) = 1.408(4); C(15)−
N(2) = 1.422(4); C(1)−F(1) = 1.380(4); C(23)−F(2) = 1.356(4);
N(2)−C(1)−N(1) = 120.9(3).
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4. The shortest distances between an o-F atom and the metal
center in complexes 11 and 12 exceed the sum of their
Figure 3. Mercury diagram of the molecular structure of the amidine 5
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): C(13)−N(1) =
1.277(3); C(13)−N(2) = 1.376(3); C(1)−N(1) = 1.399(3); C(7)−
N(2) = 1.404(3); C(8)−F(6) = 1.343(4); C(12)−F(10) = 1.337(4);
C(2)−F(1) = 1.345(1); C(6)−F(5) = 1.349(3); N(2)−C(13)−N(1)
= 117.8(2).
Figure 4. Mercury diagram of the molecular structure of the amidine 6
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): C(13)−N(1) =
1.397(3); C(13)−N(2) = 1.297(3); C(1)−N(1) = 1.412(3); C(7)−
N(1) = 1.388(3); C(8)−F(6) = 1.353(3); C(11)−F(9) = 1.348(3);
C(2)−F(1) = 1.334(3); C(6)−F(5) = 1.335(3); N(2)−C(13)−N(1)
= 112.4(2).
Figure 5. Mercury diagram of the molecular structure of complex 7
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): Ti(1)−N(1) =
2.1018(18); Ti(1)−N(2) = 2.1769(19); Ti(1)−N(5) = 1.893(2);
Ti(1)−N(4) = 2.091(2); Ti(1)−N(3) = 2.222(2); Ti(1)−N(6) =
1.899(2); C(1)−N(1) = 1.340(3); C(1)−N(2) = 1.312(3); C(17)−
N(3) = 1.308(3); C(17)−N(4) = 1.330(3); N(2)−Ti(1)−N(1) =
60.92(7); N(1)−Ti(1)−N(5) = 94.84(8); N(4)−Ti(1)−N(6) =
96.97(10); N(1)−Ti(1)−N(2)-C(1) = 0.01; N(4)−Ti(1)−N(3)−
C(17) = 2.09.
Figure 6. Mercury diagram of the molecular structure of complex 9
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): Ti(1)−N(1) =
2.214(5); Ti(1)−N(2) = 2.120(5); Ti(1)−N(5) = 1.893(5); Ti(1)−
N(4) = 2.105(5); Ti(1)−N(3) = 2.234(5); Ti(1)−N(6) = 1.898(5);
C(1)−N(1) = 1.322(7); C(1)−N(2) = 1.344(7); C(17)−N(3) =
1.334(7); C(17)−N(4) = 1.350(7); N(2)−Ti(1)−N(1) = 60.55(17);
N(1)−Ti(1)−N(5) = 91.3(2); N(3)−Ti(1)−N(6) = 103.6(2);
N(1)−Ti(1)−N(2)−C(1) = 2.23; N(4)−Ti(1)−N(3)−C(17) = 3.07.
Organometallics Article
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5. corresponding van der Waals radii (4.546 Å in complex 11 and
3.947 Å in complex 12),15
indicating the absence of any notable
interaction between the metal center and the F atoms of the
fluorinated aryl substituents.
Despite their similar solid-state structures, complexes 11 and
12 display a completely different behavior in solution. In the
19
F NMR of complex 12, only three signals are observed, and in
the 1
H NMR only one set of signals corresponding to the
isopropyl moieties is detected. The persistence of these
observations even at low temperatures (−50 °C precipitating
temperature of the complex) indicates that a rapid dynamic
behavior of the complex 12 (from Δ to Λ via an open−close
ligand mechanism) is operative even at low temperatures.
Interestingly, for the rest of the complexes the same rapid
dynamic behavior was also observed at low temperatures. From
the crystal structure it is apparent that a significant barrier to
the rotation of the pentafluorophenyl ring exists in both
complexes, since the overlap of the o-F with the methyl groups
of the isopropyl moiety; however, this interaction is observed
only for complex 11. For complex 11, a very informative and
complex comprehensive spectrum in both 1
H and 19
F NMR is
obtained at low temperature. The dynamic process for complex
11 was studied with variable-temperature 19
F and 1
H
measurements, and the respective spectra are presented in
Figures 9 and 10.
The outcome of the variable-temperature NMR analysis (1
H,
19
F) indicates that only two species (11A,B) are present in
solution and their ratio, in addition to the different temperature
measurements, is kept constant (Figures 9−11 and Table 1).
Complex 11A shows a dynamic behavior as a function of the
temperature, whereas complex 11B exhibits no dynamic
behavior in solution over the examined temperature range.
From the line broadening analysis, complex 11A exhibits the
dynamic processes (i) rotation of the methyl groups within
each isopropyl group and (ii) dynamic equilibration of the
isopropyl groups between the two amidinate ligands within the
complex with the thermodynamic value measured of ΔH⧧
=
13.4(0.4) kcal mol−1
(see the corresponding Eyring plot in the
Supporting Information), together with the equilibration of the
perfluorinated aromatic rings. Hence, it seems plausible that
complex 11A has one open ligand (κ1
) and one closed chelated
ligand (κ2
), whereas in complex 11B both ligands are
connected to the metal center in a κ2
fashion (at high
temperature a broadening of all the spectra lines is appreciable,
suggesting a high energy of activation toward the interconver-
sion of 11A to 11B). The two complexes 11A,B were
characterized by 1
H and 19
F COSY at 227 K (Figures 11 and
12) and also at 365 K (see the Supporting Information). It is
important to point out that the presence of the symmetric C2v
complex 11, having two κ1
chelating ligands, was not observed
in solution even when one crystal was dissolved (based on the
1
H and 19
F NMR correlating data). In the 1
H NMR at 365 K
the signals were broadened, and no final product (coalescence
process/correlation among the two complexes) was obtained.
Heating beyond 365 K induces a rapid decomposition of the
complexes. It is very interesting to follow the signals of the
isopropyl moieties in both complexes, showing a nice crossover
of the signals, which are also verified in the COSY spectra at the
different temperatures. The ratio among the complexes 11A,B
is maintained constant, 70:30, respectively, regardless of the
temperature, as was confirmed by both the 1
H and 19
F NMR
(see the integration of signals in Table 1). The variable-
temperature 19
F NMR spectra were very informative, and full
assignment of the two complexes was possible via their
chemical shifts, 2D correlations at the different temperatures,
and the corresponding integrations. It is important to point out
that two possible geometrical isomers (cis and trans isomers)
could be responsible for the signals obtained in complex 11A as
presented in Figure 11. Our attempts to obtain crystals of just
11A were unsuccessful; however, for the trans isomer a high
energy of activation toward its equilibration to complex 12
would be expected.
All of the complexes were tested as suitable catalysts for the
polymerization of propylene. Catalytically active species were
generated by the reaction of the complexes with methyl-
Figure 7. Mercury diagram of the molecular structure of complex 11
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): Ti(1)−N(1) =
2.124(6); Ti(1)−N(2) = 2.247(5); Ti(1)−N(3) = 1.889(5); C(13)−
N(1) = 1.356(8); C(13)−N(2) = 1.289(8); F(10)−Ti(1) = 4.546;
N(2)−Ti(1)−N(1) = 59.5(2); N(2)−Ti(1)−N(3) = 90.90(2);
N(2)−Ti(1)−N(1)−C(13) = 4.78.
Figure 8. Mercury diagram of the molecular structure of complex 12
(25% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Representative bond lengths (Å) and angles (deg): Zr(1)−N(2) =
2.242(3); Zr(1)−N(3) = 2.341(3); Zr(1)−N(1) = 2.031(3); C(1)−
N(2) = 1.351(4); C(1)−N(3) = 1.331(4); F(5)−Zr(1) = 3.947;
N(2)−Zr(1)−N(3) = 56.78(9); N(2)−Zr(1)−N(1) = 94.65(11);
N(2)−Zr(1)−N(3)−C(1) = 6.62.
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6. alumoxane (MAO) in a 1:1000 ratio in toluene. The
polymerizations were performed with an excess of propylene
at room temperature for 3 h (Table 2). The precatalyst 11
exhibits an activity of 97 kg mol−1
h−1
at room temperature,
while complex 12 showed a similar reactivity of 113 kg mol−1
h−1
, but only at elevated temperature (60 °C), since at room
temperature no polymerization was obtained. Unlike the case
for the benzamidinates, no stereospecific fraction was obtained,
Figure 9. Variable-temperature 19
F NMR spectra for complex 11. The labels in the spectrum correspond to the different fluorine atoms as defined in
Figure 11.
Figure 10. Variable-temperature 1
H NMR for complex 11. The labels in the spectrum correspond to the different atoms in the corresponding
complexes as defined in Figure 11.
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7. presumably due to the dynamic behavior of the complex 11A
forming various active species, as corroborated by the large
molecular weight distribution of the obtained polymers. The
mmmm pentad frequency (6−7%) was found in all cases, and in
some cases the polymers were obtained as elastomeric
materials, due to their molecular weight.16
The polymers that
were obtained with complex 12 were atactic, and due to their
low molecular weight, the consistency of these resulting
materials was a tacky liquid. End group analysis has revealed
that β-H-elimination/transfer to a monomer is responsible for
the chain transfer process.
Interestingly, introduction of a fluorine atom at the meta
position in complex 8 causes the formation of polypropylene
with a higher molecular weight as compared to that for complex
7, presumably due to chain transfer suppression, whereas the p-
fluorine complex 9 induces a higher insertion rate as compared
to complex 7. The most interesting result is obtained with the
fluoronaphthyl complex 10, which exhibits low activity but
affords high-molecular-weight polymer, suggesting that the
interaction of the fluorine atom with the metal center or the
growing chain may be impeding chain termination as well as
monomer insertion.
■ CONCLUSIONS
In this work we reported a series of new fluorinated titanium
and zirconium bis(amidinates). Variable-temperature 1
H NMR
revealed the dynamic behavior of the titanium complex 11A
with rearrangement of the ligand about the metal center. The
dynamic behavior of the resulting fluorinated zirconium and
titanium bis(amidinates) leads to the complete loss of C2
symmetry followed by loss of stereospecificity in the polymer-
ization of propylene. Substitution with fluorine atoms on
different positions of the N-aryl substituent revealed that
fluorine atoms at the meta position suppress termination of the
growing chain, while p-F accelerates the insertion of monomer.
■ EXPERIMENTAL SECTION
All manipulations of air-sensitive materials were carried out with the
rigorous exclusion of oxygen and moisture in oven-dried or flamed
Schlenk-type glassware on a dual-manifold Schlenk line or interfaced
to a high-vacuum (10−5
Torr) line or in a nitrogen-filled glovebox (M.
Braun) with a medium-capacity recirculator (1−2 ppm O2). Argon and
nitrogen were purified by passage through a MnO oxygen removal
Figure 11. Assignment of fluorine atoms in 11A (both plausible isomers) and 11B at 227.2 K.
Table 1. Integration of H and F (Ortho) Atoms of Species
11A,B at the Lowest and the Highest Temperatures with No
Coalescencesa
1
H NMR 19
F NMR
temp
(K) group integration group integration
227.2 A(CH),
B(CH)
1.00, 0.31 B(Fd), B(Fa) 0.628, 0.654
A(CH3),
B(CH3)
3.00, 1.84 A(Fa), A(Fb),
A(Fe), A(Fh)
1.03, 1.00, 1.03,
1.01
365.3 A(CH),
B(CH)
1.00, 0.35 B(ortho) left,
B(ortho) left
1.00, 1.01
A(CH3),
B(CH3)
5.87, 1.94 A(ortho) 3.15
a
The legends at the spectrum correspond to the different atoms in the
corresponding complexes as defined in Figure 11.
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8. column and a Davison 4 Å molecular sieve column. Analytically pure
CH2Cl2 and CDCl3 were used without any purification, and all other
solvents (toluene, hexane, toluene-d8, C6D6) were dried over Na/K
alloy, degassed by three freeze−pump−thaw cycles and vacuum-
transferred prior to use. The final products 1−6 are air stable and do
not need to be stored under inert conditions. All anilines and
hexamethyldisiloxane (TMS2O) were purchased from Sigma-Aldrich
and used without further purification. Ti(NMe2)4, Zr(NMe2)4,17
and
8-fluoronaphthalen-1-ylamine18
were prepared by literature proce-
dures. NMR spectra were recorded on a Bruker Avance 300
spectrometer. NMR spectra for variable-temperature experiments
were recorded on a Bruker Avance 600 spectrometer; the temperature
was calibrated with MeOH (low temperature) and ethylene glysol
(high temperature). 1
H and 13
C chemical shifts are referenced to
internal solvent resonances and reported relative to TMS. 19
F chemical
shifts were referenced according to IUPAC recommendations.19
The
experiments with metal complexes were conducted in Teflon-sealed
NMR tubes (J. Young) after the preparation of the sample under
Figure 12. 19
F COSY (left) and 1
H COSY (right) of complex 11 at 227.2 K.
Table 2. Propylene Polymerization Results with the
Bis(amidinate)dimethylamido Titanium and Zirconium
Complexes 7−12a
precat. activityb
Mw PD Ri Rt
11 97.0 251 000c
8.3 2.4 × 10−3
3.4 × 10−5
7 33.5 55 000 3.9 1.3 × 10−3
3.9 × 10−5
8 35.0 142 500 3.9 1.3 × 10−3
1.5 × 10−5
9 63.2 82 000 3.7 2.5 × 10−3
4.7 × 10−5
10 1.7 82 000 2.6 5.2 × 10−5
6.6 × 10−8
10d
4.9 91 500 4.4 1.3 × 10−4
2.7 × 10−6
12d
113.0 4 500 4.5 3.1 × 10−3
1.3 × 10−3
a
Reaction conditions: catalyst:MAO 1:1000 in 6 mL of toluene, 30 mL
of propylene, room temperature, 3 h. b
Activity in kg (mol of
catalyst)−1
h−1
. c
Bimodal signal in GPC analysis. d
Polymerization
temperature 60 °C.
Table 3. Crystallographic Data for Amidine Ligands 3−5 and Imidazole 6
amidine 3 amidine 4 amidine 5 imidazole 6
empirical formula C16H16F2N2 C24H20F2N2 C16H8F10N2 C16H7F9N2
formula wt 274.31 374.42 418.24 398.24
T (K) 293(2) 293(2) 293(2) 293(2)
λ (Å) 0.710 73 0.710 73 0.710 73 0.710 73
cryst syst triclinic triclinic monoclinic monoclinic
space group P1̅ P1̅ P21/c C2/c
a (Å) 8.579(2) 11.659(2) 8.029(2) 16.809(3)
b (Å) 11.799(2) 11.707(3) 12.698(2) 16.277(3)
c (Å) 14.702(3) 15.017(3) 16.824(3) 11.616(2)
α (deg) 101.20(3) 93.24(2)
β (deg) 90.71(3) 112.97(3) 97.21(3) 99.09(3)
γ (deg) 91.07(3) 100.56(3)
V (Å3
) 1459.4(5) 1993.4(7) 1701.7(6) 3138.2(10)
Z 4 4 4 8
ρ (g/cm3
) 1.248 1.248 1.633 1.686
μ(Mo Kα) (mm−1
) 0.092 0.086 0.175 0.176
R1, wR2 (I >2σ(I)) 0.0536, 0.1350 0.0750, 0.1898 0.0489, 0.1258 0.0457, 0.1155
R1, wR2 (all data) 0.0831, 0.1482 0.1616, 0.2191 0.1113, 0.1494 0.0936, 0.1322
GOF on F2
1.052 1.051 0.915 0.94
F(000) 576 784 832 1584
θ range for data collecn (deg) 2.03−25.02 1.65−24.96 2.44−25.86 2.35−25.01
no. of collected/unique rflns 14 056/5121 15 985/6911 12 426/3166 2769/2769
largest diff peak, hole (e/Å3
) 0.131, −0.167 0.449, −0.185 0.268, −0.215 0.164, −0.132
Organometallics Article
dx.doi.org/10.1021/om300702s | Organometallics 2012, 31, 7404−74147411
9. anaerobic conditions, with dried toluene-d8 or C6D6. The molecular
weights and polydispersities of the polymers were determined by the
gel permeation chromatography (GPC) method on a Varian PL-GPC
220 instrument using 1,2,4-trichlorobenzene as the mobile phase at
160 °C. Polystyrene standards were used for the standard calibration
curve of GPC.
X-ray Crystallographic Measurements. The single-crystal
material was immersed in Paratone-N oil and was quickly fished
with a glass rod and mounted on a Kappa CCD diffractometer under a
cold stream of nitrogen. Data collection was performed using
monochromated Mo Kα radiation using φ and ω scans to cover the
Ewald sphere.20
Accurate cell parameters were obtained with the
amount of indicated reflections (Tables 3 and 4).21
The structure was
solved by SHELXS-97 direct methods22
and refined by the SHELXL-
97 program package.23
The atoms were refined anisotropically.
Hydrogen atoms were included using the riding model. Software
used for molecular graphics: Mercury 2.4. The cell parameters and
refinement data are presented in Tables 3 and 4.
Synthesis of PPSE. A mixture of 14.2 g of phosphorus pentoxide
(P2O5), 25.6 g of hexamethylsiloxane (TMS2O), and 30 mL of CH2Cl2
was refluxed for 30 min under a slow flow of N2. After the mixture
became a colorless liquid, the flask was placed under vacuum and
slowly heated to 160 °C. The resulting viscous oil was used
immediately for the synthesis of the corresponding amidine.
General Procedure for the Synthesis of Amidines. To the
PPSE prepared from 14.2 g of P2O5 at 180 °C under an N2 flow was
added 1 equiv (1.25 mmol) of isobutyric acid, and the mixture was
stirred for 5 min; during this time the reaction was heated to 200 °C.
Two equivalents (2.5 mmol) of the corresponding aniline was then
added dropwise with syringe to the reaction mixture, and the resulting
viscous liquid was stirred at this temperature for 5 h. After that time
the reaction mixture was made strongly basic (pH about 12) by adding
a 1 M solution of NaOH. The resulting biphasic mixture was extracted
three times with CH2Cl2; the combined organic fractions were washed
with water, dried over Na2SO4, filtered and all volatiles removed under
reduced pressure. The resulting crude product was purified by column
chromatography on silica using a 1/1 hexane/CH2Cl2 mixture as
eluent. Alternatively, the crude mixture may be separated by silica gel
chromatography using 80/20 hexane/ethyl acetate as eluent.
1 (amidine): yield 85.2%; 1
H NMR (CDCl3) δ 7.27−7.163 (5H,
m), 6.98−6.84 (5H, m), 5.72 (1H, br), 2.84 (1H, m, 3
J = 6.87 Hz),
0.71 (6H, d, 3
J = 6.87 Hz); 13
C NMR δ 158.2, 150.7, 140.6, 128.9,
128.5, 122.2, 121.5, 119.3, 29.0, 19.9.
2 (amidine): yield 89.8%; 1
H NMR (tol-d8) δ 7.02 (4H, m), 6.71
(4H, m), 5.76 (1H, br), 2.76 (1H, sept, 3
J = 7.32 Hz), 0.72 (6H, d, 3
J =
7.33 Hz); 19
F NMR δ −112.85 (1F, s), −111.81 (1F, s); 13
C NMR δ
164.4, 159.3, 151.8, 141.5, 129.9, 117.0, 114.6, 109.1, 108.9, 108.3,
106.7, 29.5, 20.7.
3: yield 91.5%; 1
H NMR (CDCl3) δ 7.29 (4H, t, 3
J = 7.65 Hz), 7.02
(2H, t, 3
J = 7.53 Hz), 6.84 (2H, t, 3
J = 7.6 Hz), 6.09 (1H, br), 2.94
(1H, sept, 3
J = 6.03 Hz), 0.85 (6H, d, 3
J = 6.06 Hz); 19
F NMR δ
−122.72 (1F, s), −120.27 (1F, s); 13
C NMR δ 171.9, 159.3, 150.1,
140.5, 137.1, 129.0, 122.5, 121.4, 119.5, 29.3, 20.0.
4: yield 83.5%; 1
H NMR (CDCl3) δ 9.75 (1H, br) 7.55 − 6.73
(12H, m), 2.98 (1H, sept, 3
J = 6.92 Hz), 1.12 (6H, d, 3
J = 6.92 Hz);
19
F NMR δ −112.85 (1F, s), −111.81 (1F, s); 13
C NMR δ 175.2,
160.2, 157.8, 136.4, 136.4, 132.5, 132.5, 127.1, 125.4(d, 1
J = 10.25 Hz),
125.2 (d, 1
J = 3.32 Hz), 123.7, 118.7, 111.2, 110.9, 37.3, 19.5.
5 (amidine): yield 28%; 1
H NMR (CDCl3) δ 4.80 (broad, 1H),
2.19 (sept, 3
J = 6.9 Hz), 0.71 (d, 3
J = 6.9 Hz); 19
F NMR δ −165.50
(1F, t, 3
J = 22.92 Hz), −164.64 (2F, t, 3
J = 20.78 Hz), −164.10 (2F, t,
3
J = 20.25 Hz), −157.64 (1F, t, 3
J = 22.38 Hz), −154.20 (2F, d, 3
J =
21.32 Hz), −146.09 (2F, d, 3
J = 21.29 Hz); 13
C NMR δ 165.2, 145.4−
136.4 (C-Fs, low broad signals), 30.9, 19.4. Anal. Calcd for
C16H8F10N2: C, 45.95; H, 1.93; N, 6.70. Found: C, 46.33; H, 1.95;
N, 6.40.
6 (imidazole): yield 69%; 1
H NMR (CDCl3) δ 1.06 (6H, d, 3
J =
6.82 Hz), 1.99 (1H, m, 3
J = 6.87 Hz); 19
F NMR (CDCl3) δ −164.10
(2F, t, 3
J = 22.61 Hz), −164.07 (1F, t, 3
J = 19.21 Hz), −163.39 (1F, q,
3
J = 22.65 Hz), −157.19 (1F, q, 3
J = 22.67 Hz), −154.20 (1F, d, 3
J =
21.32 Hz), −153.21 (1F, d, 3
J = 22.17 Hz), −145.65 (2F, d, 3
J = 19.17
Hz); 13
C NMR δ 162.3, 145.4−136.4 (C-Fs, low broad signals), 26.5,
20.5. Anal. Calcd for C16H7F9N2: C, 48.26; H, 1.77; N, 7.03. Found: C,
48.15; H, 1.68; N, 6.89.
General Procedure for the Synthesis of L2M(NMe2)2
Complexes (7−12). A toluene solution of 2 equiv (0.88 mmol) of
the corresponding ligand was added dropwise to a solution of 1 equiv
of M(NMe2)4 (0.44 mmol) in toluene at room temperature, and the
reaction mixture was stirred overnight. After this period of time all
Table 4. Crystallographic Data for Complexes 7, 9, 11, and 12
complex 7 complex 9 complex 11 complex 12
empirical formula C36H46N6Ti C54H63F6N9Ti1.50 C36H26F20N6Ti C18H13F10N3Zr0.50
formula wt 610.69 1023.98 970.53 506.92
T (K) 293(2) 240(2) 240(2) 240(2)
λ (Å) 0.710 73 0.710 73 0.710 73 0.710 73
cryst syst monoclinic triclinic monoclinic monoclinic
space group P21/c P1̅ C2/c C2/c
a (Å) 16.370(3) 11.411(2) 11.929(2) 12.079(2)
b (Å) 10.527(2) 19.071(4) 17.908(3) 17.913(4)
c (Å) 20.018(4) 26.934(5) 18.271(4) 18.634(4)
α (deg) 101.71(3)
β (deg) 98.81(3) 97.29(3) 98.15(3) 98.97(3)
γ (deg) 100.20(3)
V (Å3
) 3408.9(11) 5567.4(18) 3863.7(12) 3982.6(14)
Z 4 4 4 8
ρ (g/cm3
) 1.19 1.222 1.668 1.691
μ(Mo Kα) (mm−1
) 0.284 0.283 0.356 0.407
R1, wR2 (I >2σ(I)) 0.0509, 0.1310 0.0866, 0.2483 0.0754, 0.1504 0.0428, 0.0920
R1, wR2 (all data) 0.0736, 0.1398 0.1403, 0.2695 0.2288, 0.1926 0.0727, 0.1011
GOF on F2
1.056 0.949 0.846 0.928
F(000) 1304 2148 1944 2016
θ range for data collecn (deg) 2.06 to 25.02 1.70 to 25.02 2.07 to 25.00 2.05 to 25.05
no. of collected/unique rflns 19 688/5917 70 805/19 135 20 758/3242 19 661/3497 (R(int) = 0.098)
largest diff peak, hole (e/Å3
) 0.483, −0.341 0.923, −0.407 0.519, −0.359 0.268, −0.871
Organometallics Article
dx.doi.org/10.1021/om300702s | Organometallics 2012, 31, 7404−74147412
10. volatiles were removed under reduced pressure, and to the resulting
residue was added hexane, causing precipitation of solid material. The
mixture was filtered, the resulting cake was washed with hexane, and
the resulting solid was dried in vacuo to give the complexes as pure
products. X-ray-quality crystals were obtained by slow evaporation of
toluene from the toluene/complex solution, unless stated otherwise.
7: yield 87.3%; 1
H NMR (tol-d8) δ 7.18 (4H, t, 3
J = 7.74 Hz), 7.07
(4H, br), 6.96 (2H, t, 3
J = 7.15), 3.07 (12H, s), 2.95 (2H, m, 3
J =
7.22), 0.91 (12H, d, 3
J = 7.22 Hz); 13
C NMR δ 174.4, 149.2, 137.5,
126.5, 123.4, 121.6, 47.5, 30.7. Anal. Calcd for C36H46N6Ti: C, 70.57;
H, 7.90; N, 13.72. Found: C, 70.21; H, 7.28; N, 12.08.
8: yield 91.5%; 1
H NMR (tol-d8) δ 6.99 (8H, m, 3
J = 7.65 Hz), 6.79
(8H, m, 3
J = 8.24 Hz), 3.11 (12H, s), 2.94 (2H, sept, 3
J = 7.08 Hz),
0.90 (12H, d, 3
J = 7.06 Hz); 19
F NMR δ −113.02 (2F, q, 3
J = 8.68
Hz); 13
C NMR δ 174.6, 165.8, 160.9, 150.3, 150.1, 129.5, 129.3, 47.0,
20.4. Anal. Calcd for C36H42F4N6Ti: C, 63.16; H, 6.48; N, 12.28.
Found: C, 61.66; H, 6.26; N, 11.34.
9: yield 86.7%; 1
H NMR (tol-d8) δ 6.92 (8H, br), 3.16 (12H, s),
2.88 (2H, sept, 3
J = 7.34 Hz), 0.89 (12H, d, 3
J = 7.35 Hz); 19
F NMR δ
−119.83; 13
C NMR δ 174.8, 162.0, 157.2, 144.6, 144.2, 115.3, 114.8,
47.1, 30.2, 20.5. Anal. Calcd for C36H42F4N6Ti: C, 63.16; H, 6.48; N,
12.28. Found: C, 62.11; H, 7.10; N,11.52.
10: yield 92.3%; 1
H NMR (tol-d8): δ 0.99 (12H, d, 3
J = 6.94 Hz),
2.29 (2H, s), 2.91 (12H, m, 3
J = 6.9 Hz), 7.448−6.733 (24H, m); 19
F
NMR δ −111.39 (dd, 3
J = 12.87 Hz, 4
J = 4.37 Hz); 13
C NMR δ
172.81, 162.80, 162.16, 158.0, 157.3, 145.9, 137.5, 136.9, 136.9, 135.7,
128.3, 127.8, 125.6, 124.9, 124.2, 121.6, 121.4, 118.4, 117.3, 110.6,
110.17, 31.0, 20.0. Anal. Calcd for C52H50F3N6Ti: C, 70.58; H, 5.92;
N, 9.50. Found: C, 76.58; H, 6.54; N, 10.11.
11: yield 84.0%; X-ray-quality crystals obtained by cooling the
saturated toluene solution from 50 °C to room temperature; 1
H NMR
(C6D6) δ 2.86 (s, 12H), 2.32 (sept, 3
J = 7.2 Hz, 2H), 0.74 (d, 3
J = 7.2
Hz, 12H); 19
F NMR spectrum at room temperature consists of broad
signals that cannot be assigned properly; 13
C NMR δ 179.6, 45.1, 31.5,
17.4. Anal. Calcd for C36H28F20N6Ti: C, 44.46; H, 2.90; N, 8.64.
Found: C, 44.93; H, 2.56; N, 8.17.
12: yield 76.2% 1
H NMR (C6D6) δ 2.59 (s, 12H), 2.33 (sept, 3
J =
6.9 Hz, 2H), 0.74 (d, 3
J = 6.9 Hz, 12H); 19
F NMR δ −148.5 (d, 3
J =
21.5 Hz, 8F), −160.30 (t, 3
J = 21.7 Hz, 4F). −163.87 (t, 3
J = 18.9 Hz,
8F); 13
C NMR δ 184.6, 40.3, 32.6, 19.4. Anal. Calcd for
C36H28F20N5Zr: C, 42.56; H, 2.78; N, 8.27. Found: C, 44.93; H,
2.30; N, 6.89.
Typical Procedure for Propylene Polymerization. Inside the
glovebox, 10 mg of the complex, the appropriate amount of the MAO
(1:1000 metal:Al ratio), and 6 mL of toluene were mixed and loaded
into a stainless steel reactor. The reactor was connected to the high-
vacuum line, and 30 mL of propylene was transferred into the reactor.
The reaction mixture was warmed to the desired temperature and
stirred for 3 h. The reaction was quenched with acetylacetone, and the
resulting polymer was washed with methanol followed by acetone. The
solvents were dried out in the vacuum oven at 50 °C. The resulting
material was fractionalized with hexane in a Soxhlet apparatus.
■ ASSOCIATED CONTENT
*S Supporting Information
Figures, tables, and CIF files giving an Eyring plot for the
dynamic process in complex 11, COSY of complex 11 at high
(365 K) and low (227 K) temperatures, and crystallographic
data for ligands 3−6 and complexes 7, 9, 11, and 12. This
material is available free of charge via the Internet at http://
pubs.acs.org.
■ AUTHOR INFORMATION
Corresponding Author
*E-mail: chmoris@tx.technion.ac.il.
Notes
The authors declare no competing financial interest.
■ ACKNOWLEDGMENTS
This research was supported by the USA-Israel Binational
Science Foundation under Contract 2008283. S.A. thanks
Raymond Rosen for his fellowship.
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