The mixed ligand complexes of Co (II), Ni (II) and Cu (II) with histidine (His.) and 8-hydroxyquinoline (Qui.) have been synthesized and characterized.The resulting complexes were characterized by vibrational and electronic spectral data, thermogravimetric studies , metal analysis and molar conductance measurements. The histidine acts as tridentate ligand, coordinating through the two nitrogen atoms of imidazole ring and the amino group and carboxylate oxygen whereas 8-hydroxyquinoline shows a bidentate nature and the coordination occurs through nitrogen of imine group and oxygen of phenol group. The experimental data suggest that a mononuclear octahedral structure with general formula [M (His.)(Qui.) H2O ] where M= Co (II), Ni (II) and [Cu (His.)(Qui.)H2O] .H2O, thermo gravimetric studies reveal the presence of coordinated water molecules in all complexes. The molar conductance measurements reveal non-electrolytic nature of complexes.
Multiple Equilibria and Chemical Distribution of Some Bio Metals With β-Amide...IOSR Journals
Abstract: Solution Chemistry of some bivalent metal ions (viz. CoII , NiII ,CuII ,ZnII ) with β-amide α-aminosuccinate (Asparagine)/ α-aminoisoverate( Valine ) (A) and 5-methyl 2,4- dioxopyrimidine ( Thymine ) (B)ligands have been analyzed. Formation constant of quaternary metal complexes and complexation equilibria at 30±1ºC and at constant ionic strength (I=0.1M NaNO3 ) have been explored potentiometrically. Formation of quaternary species in addition to hydroxyl, protonated, binary and ternary species have been reported. Overall formation constant have been evaluated using SCOGS computer program.Species distribution curves of complexes have been plotted as a function of pH to visualize the equlibria system and was refined using ORIGIN program.The metal ligand formation constant of MA,MB,MAB and M1M2AB type of complexes follow Irving William order. The order of stability constants of quaternary systems have been observed as: Cu – Ni > Cu –Zn > Cu–Co > Ni – Zn > Ni – Co > Co –Zn. Solution structures of metal complexes with said ligands have been compared and discussed.
Spectral studies of 5-({4-amino-2-[(Z)-(2-hydroxybenzylidene) amino] pyrimidi...IOSR Journals
Some transition metal ions Complexes with 5-({4-amino-2-[(Z)-(2-hydroxybenzylidene) amino]
pyrimidin-5-yl} methyl)-2,3,4-trimethoxybenzene were prepared and characterized by elemental analyses,
Infrared , magnetic moment, electronic spectra , mass spectra, X-ray powder diffraction, molar conductance
and thermal analysis (TGA). The complexes have general formulae [ML2.2H2O] {where M = Mn (II), Co (II), Ni
(II), Cu (II), Zn (II), Pd (II) and Pt (II). The coordination behavior of the metal ions towards to the investigated
Schiff base takes place through –C=N,-NH2 and –OH groups. The obtained C, H and N elemental analysis data
showed the Metal: Ligand ratio is 1:2 [M: L] ratio. The molar conductance data reveal that all the metal
complexes are non-electrolytic in nature. From the magnetic moments the complexes are paramagnetic except
Zn metal ion complexes have octahedral geometry with coordination number eight. The thermal behavior of
these complexes shows that, the hydrated complexes have loses two water molecules and immediately followed
by decomposition of the anions and ligand molecules in the second and third stage. The Schiff bases and metal
complexes show good activity against some bacteria. The antimicrobial results indicate that, the metal
complexes have better antimicrobial activity as compared to the prepared Schiff base.
Multiple Equilibria and Chemical Distribution of Some Bio Metals With β-Amide...IOSR Journals
Abstract: Solution Chemistry of some bivalent metal ions (viz. CoII , NiII ,CuII ,ZnII ) with β-amide α-aminosuccinate (Asparagine)/ α-aminoisoverate( Valine ) (A) and 5-methyl 2,4- dioxopyrimidine ( Thymine ) (B)ligands have been analyzed. Formation constant of quaternary metal complexes and complexation equilibria at 30±1ºC and at constant ionic strength (I=0.1M NaNO3 ) have been explored potentiometrically. Formation of quaternary species in addition to hydroxyl, protonated, binary and ternary species have been reported. Overall formation constant have been evaluated using SCOGS computer program.Species distribution curves of complexes have been plotted as a function of pH to visualize the equlibria system and was refined using ORIGIN program.The metal ligand formation constant of MA,MB,MAB and M1M2AB type of complexes follow Irving William order. The order of stability constants of quaternary systems have been observed as: Cu – Ni > Cu –Zn > Cu–Co > Ni – Zn > Ni – Co > Co –Zn. Solution structures of metal complexes with said ligands have been compared and discussed.
Spectral studies of 5-({4-amino-2-[(Z)-(2-hydroxybenzylidene) amino] pyrimidi...IOSR Journals
Some transition metal ions Complexes with 5-({4-amino-2-[(Z)-(2-hydroxybenzylidene) amino]
pyrimidin-5-yl} methyl)-2,3,4-trimethoxybenzene were prepared and characterized by elemental analyses,
Infrared , magnetic moment, electronic spectra , mass spectra, X-ray powder diffraction, molar conductance
and thermal analysis (TGA). The complexes have general formulae [ML2.2H2O] {where M = Mn (II), Co (II), Ni
(II), Cu (II), Zn (II), Pd (II) and Pt (II). The coordination behavior of the metal ions towards to the investigated
Schiff base takes place through –C=N,-NH2 and –OH groups. The obtained C, H and N elemental analysis data
showed the Metal: Ligand ratio is 1:2 [M: L] ratio. The molar conductance data reveal that all the metal
complexes are non-electrolytic in nature. From the magnetic moments the complexes are paramagnetic except
Zn metal ion complexes have octahedral geometry with coordination number eight. The thermal behavior of
these complexes shows that, the hydrated complexes have loses two water molecules and immediately followed
by decomposition of the anions and ligand molecules in the second and third stage. The Schiff bases and metal
complexes show good activity against some bacteria. The antimicrobial results indicate that, the metal
complexes have better antimicrobial activity as compared to the prepared Schiff base.
Studies On The Cobalt(II) And Copper(II) Complexes Of 2,5-Substituted 1,3,4-T...IOSR Journals
New metal complexes of Co(II),and Cu(II) have been synthesized by reacting metal solutions with the ligand 2,5-substituted 1,3,4-triazoles in alcoholic medium. Molecular formulae of the complexes were determined and are further characterized by IR spectroscopy, magnetic susceptibility and molar conductance studies. The ligand acts as a bidentate ligand co-ordinating through the nitrogen atoms present in the ring.
Synthesis, Characterization and antimicrobial activity of some novel sulfacet...iosrjce
IOSR Journal of Applied Chemistry (IOSR-JAC) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Synthesis and characterization of mixed ligand complexes of some metals with ...Taghreed Al-Noor
This paper presents the synthesis and study of some new mixed-liagnd complexes containing nicotinamide(C6H7N2O) symbolized (NA) and phenylalanine (C9H11NO2)symbolized (pheH)] with some metal ions.
The resulting products were found to be solid crystalline complexes which have been characterized by :Melting points, Solubility, Molar conductivity.
determination the percentage of the metal in the complexes by flame(AAS), magnetic susceptipibility, Spectroscopic Method [FT-IR and UV-Vis].
The proposed structure of the complexes using program , chem office 3D(2006) .
The general formula have been given for the prepared complexes :[M(NA)2(phe)]cl
M(II): Mn(II) ,Co(II) , Ni(II) , Cu(II) , Zn(II) , Cd(II) & Hg(II) .
NA = Nicotinamide= C6H7N2O
Phe - = phenylalanine ion = C9H10NO2
Synthesis and characterization of some metal complexes of 2- Phenyl-3,4-dihyd...IOSRJAC
2-Phenyl-3,4-dihydro-quinazolin-4-yloxy)-acetic acid (L1) metal complexes with Mn2+ , Co2+, Ni2+ Cu2+ , and Zn2+ ions were studied and the structure of the complexes were elucidated using elemental analyses, infrared (IR), 1H nuclear magnetic resonance (NMR), magnetic moment and thermal analysis measurements. Besides the characterization of complexes by physicochemical technique, Biological activities of the synthesized complexes were examined against some microbial strains for evaluation of antibacterial and antifungal activities.
synthesis and characterization of hydrazone ligand and their metal complexesMUBASHIRA M
This slide mainly contain the synthesis, characterization of a few hydrazine based heterocyclic ligand such as hydralazone and phenyl hydralazone and also their metal complexes. so in this work, my aim is to synthesise the ligands; 2-thiophenecarboxylaldehydehydralazone and 2,3-butanedionephenylhydrazone. also to characterized the synthesised hydrazones by different physiochemical techniques.
Studies On The Cobalt(II) And Copper(II) Complexes Of 2,5-Substituted 1,3,4-T...IOSR Journals
New metal complexes of Co(II),and Cu(II) have been synthesized by reacting metal solutions with the ligand 2,5-substituted 1,3,4-triazoles in alcoholic medium. Molecular formulae of the complexes were determined and are further characterized by IR spectroscopy, magnetic susceptibility and molar conductance studies. The ligand acts as a bidentate ligand co-ordinating through the nitrogen atoms present in the ring.
Synthesis, Characterization and antimicrobial activity of some novel sulfacet...iosrjce
IOSR Journal of Applied Chemistry (IOSR-JAC) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of applied chemistry and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Chemical Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Synthesis and characterization of mixed ligand complexes of some metals with ...Taghreed Al-Noor
This paper presents the synthesis and study of some new mixed-liagnd complexes containing nicotinamide(C6H7N2O) symbolized (NA) and phenylalanine (C9H11NO2)symbolized (pheH)] with some metal ions.
The resulting products were found to be solid crystalline complexes which have been characterized by :Melting points, Solubility, Molar conductivity.
determination the percentage of the metal in the complexes by flame(AAS), magnetic susceptipibility, Spectroscopic Method [FT-IR and UV-Vis].
The proposed structure of the complexes using program , chem office 3D(2006) .
The general formula have been given for the prepared complexes :[M(NA)2(phe)]cl
M(II): Mn(II) ,Co(II) , Ni(II) , Cu(II) , Zn(II) , Cd(II) & Hg(II) .
NA = Nicotinamide= C6H7N2O
Phe - = phenylalanine ion = C9H10NO2
Synthesis and characterization of some metal complexes of 2- Phenyl-3,4-dihyd...IOSRJAC
2-Phenyl-3,4-dihydro-quinazolin-4-yloxy)-acetic acid (L1) metal complexes with Mn2+ , Co2+, Ni2+ Cu2+ , and Zn2+ ions were studied and the structure of the complexes were elucidated using elemental analyses, infrared (IR), 1H nuclear magnetic resonance (NMR), magnetic moment and thermal analysis measurements. Besides the characterization of complexes by physicochemical technique, Biological activities of the synthesized complexes were examined against some microbial strains for evaluation of antibacterial and antifungal activities.
synthesis and characterization of hydrazone ligand and their metal complexesMUBASHIRA M
This slide mainly contain the synthesis, characterization of a few hydrazine based heterocyclic ligand such as hydralazone and phenyl hydralazone and also their metal complexes. so in this work, my aim is to synthesise the ligands; 2-thiophenecarboxylaldehydehydralazone and 2,3-butanedionephenylhydrazone. also to characterized the synthesised hydrazones by different physiochemical techniques.
Synthesis and Characterization of Template Cr(III),Fe(III), Mn(II), Cd(II) an...IOSR Journals
A new series of tetradentate N2O2 acyclic complexes of type [M(L)X2]Xn where M = Mn(II), Cd, Cr(III) and Fe(III); L is tetradentate acyclic Schiff base formed via condensation reaction, and X = Cl-, n=1 for M(III), have been prepared on the basis of condensation of 2,6-diaminopyridine and 1,4-dihydro-quinoxalin-2, 3-dione by template method. The complexes are formulated as: [M(L)Cl]Cl where M=Cr, Fe(III),[MLCl2],MII=Mn, Cd(II) and [VOL]SO4 on the basis of elemental analyses,molar conductance and other spectral data. The organic moiety formed up on template condensation behaves as tetradentate N2O2 system through the two azomethine nitrogen atoms of –C=N- and the participation of O atoms of -C=O in 2-position of pyrazine ring. However, the pyridine nitrogen atom does not take part in coordination as confirmed by FTIR,UV-Visible and H NMR spectroscopy data. The newly template metal complexes have characterized with the help of various spectral techniques H NMR,13C NMR, F.T.I.R, elemental analyses, electronic spectra, molar conductivity measurements and magnetic susceptibilities. The octahedral geometry has been proposed for Cr(III),Fe(III), Mn (II) and Cd(II) while vanadyl complex was square pyramid configuration respectively
The aim of the study is to establish new accurate
Turbidometrical measurement of Sickle Hemoglobin using
spectrophotometer instead of using naked eyes. Moreover, the
study aimed to find out the most suitable filter and reducing
reagent, which gives best result to improve the outcome of
Solubility test. The study also intended to find out correlation
between readings and previous transfusions as well as Jaundice.
The study was carried out in Khartoum state among patients
with sickle cell trait who were attending Khartoum educational
hospital, Gafer Ibn Aouf Clinic and STAC International Centre
Laboratory.
Forty, 26 female and 14 male patients were recruited for the
study. Of them, 34 were children and 6 were adults over 20 years
old. There were also 30 normal persons recruited as control
group for comparison.
Results showed that 600 Nanometer is the best filter, which
yielded highest light absorbance with significant statistical
difference, and Na Meta-bisulphite is the best reducing agent
because it produced turbidity more intense than Na Dithionate
reagent. There is no significant correlation between reading and
previous transfusion and jaundice. Therefore, the study
recommend to use Na Meta-bisulphite for processing blood
samples in Solubility test and to read the final reaction
(Turbidity) by spectrophotometer using 600 Nanometer filter.
Anthranillic acid and tributylphosphine4652 6725-1-pbTaghreed Al-Noor
Mixed ligand complexes of bivalent metal ions, viz; Co(II), Ni(II), Cu(II) and Zn(II) of the
composition [M(A)2((PBu3)2]in(1:2:2)(M:A:(PBu3). molar ratio, (where A- Anthranilate ion
,(PBu3)= tributylphosphine. M= Co(II),Ni(II),Cu(II) and Zn(II).
The prepared complexes were characterized using flame atomic absorption, by FT-IR,
UV/visible spectra methods as well as magnetic susceptibility and conductivity measurements. The
metal complexes were tested in vitro against three types of pathogenic bacteria microorganisms:
(Staphylococcus, Klebsiella SPP .and Bacillas)to assess their antimicrobial properties. Results. The
study shows that all complexes have octahedral geometry; in addition, it has high activity against
tested bacteria. Based on the reported results, it may be concluded that.The results showed that the
deprotonated ligand(nthranilc acid ) to anthranilate ion (A-) by using (KOH) coordinated to metal
ions as bidentate ligand through the oxygen atom of the carboxylate group (−COO−), and the
nitrogen atom of the amine group (-NH2), where the Tributylphosphine coordinated as a
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Synthesis and Characterization of New Complexes of 2-(6-Methoxybenzo[d]thiazo...IOSR Journals
Abstract: The synthesis and characterization of manganese (ІІ), cobalt (ІІ), nickel (ІІ), copper (ІІ), zinc (ІІ), cadmium (ІІ) and mercury (ІІ) bidentate 2-(6-methoxybenzo[d]thiazol-2-ylamino)-2-phenyl acetonitrile ligand which was prepared from Benz aldehyde and 6-methoxybenzo[d]thiazol-2-amine in the presence of KCN and acidic medium. The complexes were synthesized by treating an ethanolic solution of the ligand with appropriate amount of metal salts [1:2] [M: L] ratio. The complexes were characterized by using metal and elemental chemical analysis, molar conductance, magnetic susceptibility measurements, FTIR , electronic spectral and mole ratio method. According to the obtained data the probable coordination geometries of manganese (ІІ), cobalt (ІІ), nickel (ІІ), copper (ІІ) zinc (ІІ), cadmium (ІІ) and mercury (ІІ) in these complexes are octahedral. All complexes were found to be non-electrolyte in absolute ethanol, and the complexes were formulated as [ML2Cl2] XH2O. Keywords: 2-(6-methoxybenzo[d]thiazol-2-ylamino)-2-phenyl acetonitrile, N2-donor, transition metals.
Synthesis, characterization and in vitro Antimicrobial activity of Cu (II) an...IOSR Journals
Abstract: Four Cu(II) and two Ni(II) complexes of azo carboxylate ligands were synthesized and characterized
by conductivity ,UV-visible and Infrared spectroscopy. The comparison of IR spectra of uncoordinated ligands
and their metal complexes indicated that ligands were coordinated to the metal through carboxylic oxygen atom
in bidented fashion. The electronic spectral data suggested square planner geometry of the complexes. The
conductivity study of the complexes indicated Cu(II) complexes are nonelectrolyte while Ni(II) complexes are
electrolyte in nature. All the complexes were tested for their in vitro antibacterial and antifungal activity against
different microbes and compared with standard drugs, Amphotericin-B and Ciprofloxacin. It was observed that
Ni(II)complexes are more effective than the corresponding Cu(II)complexes.Cu(II) complexes were found to be
inactive against the tested fungal species but they show moderate activity against the tested bacterial species.
One of the Ni(II) complex was found to be active in both fungal and bacterial species and also found to be more
effective than the other complexes.
Synthesis and Characterization of Thermal Analysis of La (Ii) Macrocyclic Com...inventionjournals
The macrocyclic complex compounds of La(II) containing a ligand having tetraoxotetrahydrazin moity are synthesized by template condensation of malonodihydrazide (C3H8N4O2) with different aldehydes. The complexes are characterized on the basis of elemental analysis, UV-visible & IR spectroscopy, magnetic moment and conductance measurement and other physical properties.Antibacterial activity of the derived complex compounds, as well as already used standard compound kanamycin, was tested on fourteen pathogenic bacteria. Given results were then compared to the efficacy of the Antibacterial activity of standard compound kanamycin used for control of these pathogenic bacteria.
METALLO - BIOACTIVE COMPOUNDS AS POTENTIAL NOVEL ANTICANCER THERAPYijac123
Mono and bi-organometallic complexes of Cu(II), Ni(II), Mn(II), Zn(II) and Ag(I) complexes with
oxaloamide ligand has much potential as therapeutic and diagnostic agents. The ligand allows the
thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for
functionalization. Specific examples involving the design of metal complexes as anticancer agents are
discussed. These complexes have been synthesized and characterized by (1H-NMR, mass, IR, UV-VIS,
ESR) spectra, magnetic moments and conductance measurements, elemental and thermal analyses. Molar
conductances in DMF solution indicates that, the complexes are non-electrolytes. The ESR spectra of solid
Cu(II) complexes (2-5) show an axial type indicating a d(X2-y2) ground state with a significant covalent
bond character. However, Mn(II) complex(9), shows an isotropic type indicating an octahedral geometry.
Cytotoxic evolution IC50 of the ligand and its complexes have been carried out. Cu(II) Complexes show
enhanced activity in comparison to the parent ligand or standard drug. Copper is enriched in various
human cancer tissues and is a co-factor essential for tumor angiogenesis processes. However, the use of
copper binding ligand to target tumor, copper could provide a novel strategy for cancer selective
treatment.
SYNTHESIS AND CHARACTERIZATION OF THERMAL ANALYSIS OF La (II) MACROCYCLIC COM...inventionjournals
The macrocyclic complex compounds of La(II) containing a ligand having tetraoxotetrahydrazin moity are synthesized by template condensation of malonodihydrazide (C3H8N4O2) with different aldehydes. The complexes are characterized on the basis of elemental analysis, UV-visible & IR spectroscopy, magnetic moment and conductance measurement and other physical properties.Antibacterial activity of the derived complex compounds, as well as already used standard compound kanamycin, was tested on fourteen pathogenic bacteria. Given results were then compared to the efficacy of the Antibacterial activity of standard compound kanamycin used for control of these pathogenic bacteria.
Synthesis, characterization, antimicrobial, anticancer and antidiabetic activ...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Synthesis and Thermal Study of Co (II), Ni (II), Cu (II) Mixed Ligand Complexes Using Histidine As Tridentate Ligand
1. IOSR Journal of Applied Chemistry (IOSR-JAC)
e-ISSN: 2278-5736.Volume 6, Issue 6, (Jan. 2014), PP 60-63
www.iosrjournals.org
www.iosrjournals.org 60 | Page
Synthesis and Thermal Study of Co (II), Ni (II), Cu (II) Mixed
Ligand Complexes Using Histidine As Tridentate Ligand
Ammar J. Alabdali1
, Farah M. Ibrahim1
1
(Department of Chemistry, College of Science/University of Al-Nahrain, Iraq)
Abstract: The mixed ligand complexes of Co (II), Ni (II) and Cu (II) with histidine (His.) and 8-
hydroxyquinoline (Qui.) have been synthesized and characterized.The resulting complexes were characterized
by vibrational and electronic spectral data, thermogravimetric studies , metal analysis and molar conductance
measurements. The histidine acts as tridentate ligand, coordinating through the two nitrogen atoms of imidazole
ring and the amino group and carboxylate oxygen whereas 8-hydroxyquinoline shows a bidentate nature and
the coordination occurs through nitrogen of imine group and oxygen of phenol group. The experimental data
suggest that a mononuclear octahedral structure with general formula [M (His.)(Qui.) H2O ] where M= Co (II),
Ni (II) and [Cu (His.)(Qui.)H2O] .H2O, thermo gravimetric studies reveal the presence of coordinated water
molecules in all complexes. The molar conductance measurements reveal non-electrolytic nature of complexes.
Keywords: Histidine, 8-hydroxyquinoline, mixed ligand complexes.
I. INTRODUCTION
Mixed ligand complexes containing amino acid as coligand are potential biomimetic models for metal-
protein interaction .[1]
Research has shown significant progress in utilization of transition metal complexes as
drugs to treat several human diseases like carcinomas, infection control, anti-inflammatory,diabetes and
neurological disorders.[2]
The geometry, number of ligands, donor groups, nature of biniding i.e.
microcoordination environment is the key to the understanding specific physiological function .[3]
Histidine is
a tridentate ligand that has an amino, imidazole, and carboxylate group as metal ion binding sites, but only a
metal ion with an octahedral coordination sphere can form a tridentate chelate.[4]
Imidazole group plays
important role in numerous bioactive compounds and pharmacological interest of the imidazole ring has already
been established. It acts as proton donor ∕ acceptor and charge transfer agent and is ligated to the metal ions in
B12 coenzyme .[5]
Ternary complexes of histidine and threonine are dominant in human serum and are
important in relation to the transport of copper in blood .[6]
Mixed ligand amino acid complexes are also of
relevance in enzyme inhibition .[7]
A pharmacological and toxicological property of amino acid complexes is another area that has drawn
lot of current attention .[8-9]
It has been found that metal complexes of Co (II) and Ni (II) with 8-hydroxyquinoline
possess antibacterial and antifungal activity .[10]
Some mixed ligands complexes of Co(II) and Fe(III) ions with malonic
acid as primary and hetetrocyclic bases viz. quinoline, iso quinoline, 8-hydroxyquinoline, pryidine, 2-aminopyridine and
2-aminophenol as secondary ligands have been prepared and their antimicrobial studies have been evaluated, the complexes
containing 8-hydroxyquinoline as secondary ligand were much more microbial activity than other complexes .[11]
Mixed ligand complexes of 8-hydroxyquinoline and o-hydroxybenzylidene-1-phenyl-2, 3-dimethyl-4-amino-3-
pyrazolin-5-on with Fe (II), Co (II), Ni (II) and Cu (II) ions were synthesized , the molar conductivity of the complexes in
DMF solution have non-electrolyte behavior and 8-hydroxyquinoline coordinate through the nitrogen and oxygen atoms.
therefore, the complexes have tetrahedral configuration.[12]
Several mixed ligand Ni(II),Cu(II) and Zn(II) complexes of 2-
amino-3-hydroxypyridine(AHP) and imidazoles viz.,, imidazole (him), benzimidazole (bim), histamine(hist) and L-
histidine(his) have been synthesized and characterized, the geometry becomes tetrahedral when mixed ligand complexes are
fomed with him, bim and hist for Cu(II) and Zn(II). All Ni (II) and Cu (II) / Zn (II) histidine mixed ligand complexes
have octahedral geometry.The complexes exhibited considerable amount of antibacterial activity and Cu (II)
complexes cleave DNA yielding scission of the sugar- phosphate backbone .[13]
Mixed ligand Zr(IV)
complexes prepared with 8-hydroxyquinoline as a primary ligand and amino acids such as L-alanine/L -
serine/glycine as a secondary ligand. Zr(II) was used due to its high coordination number and ability to form
stable complexes. These complexes were characterized and screened for their antibacterial, antifungal and
cytotoxic properties .[14]
Kinetics and mechanism of thermal decomposition of o-vanilline-L-histidine
complexes of some transition metal ions in which histidine acts as a tridentate ligand and an octahedral structure
for the complexes has been reported .[15]
Synthesis, structural, coordination and thermal stability studies of
mixed ligand complexes of histidine with other ligands (adenine/guanine/ethylenediamine, diethylenetriamine
or N,N,N,
N,,
,N,,,
-pentamethyldiethylenetriamine, glycine or L-alanine, histamine and diethylglyoxime) have
been carried out .[16-18]
In this work, we report the preparation and characterization of mixed ligand complexes with
histidine as tridentate and 8-hydroxyquinoline as bidentate ligands.
2. Synthesis and Thermal Study of Co (II), Ni (II), Cu (II) Mixed Ligand Complexes Using Histidine…
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II. EXPERIMENTAL
2.1Chemicals
Chemical reagents and starting materials were obtained from Fluka and BDH.
2.2 Synthesis of mixed ligand complexes
A solution of histidine was prepared by dissolving it in one equivalent of sodium hydroxide. The
solution of 8-hydroxyquinoline was prepared by dissolving it in ethanol. The solution of metal ions Co (II), Ni
(II) and Cu (II) were prepared in one equivalent of hydrochloric acid. To prepare metal complex, the two
dissolved ligands were mixed with 0.1 mol.L-1
metal ion solution in 1:1:1 molar ratio at room temperature and
the PH >7 with total volume equal to 10 ml, the mixing started with addition of histidine to metal then followed
by adding 8-hydroxyquinoline. The PH of solution was adjusted by NaOH. The color of mixture was change
and refluxed for 4 hours, the colored product was collected by filteration and washed several times with 50٪
ethanol-water mixture and dried in an oven at 50 ˚C for about one day.
2.3 Instrumentation
Melting points were recorded by using Gallenkamp M.F.B. 600.01F of melting point apparatus .
Infrared spectra were recorded using FTIR 8300 Shimadzu as KBr disk in the range (4000 - 600) cm-1
.UV-
Visible spectra were measured using Shimadzu UV-Vis 160A Ultra-violet spectrophotometer at room
temperature using silica cells of 1.0 cm length. The metal percent in the prepared complexes were determined
using Shimadzu 680 cc-flame. Conductivity measurements of 0.001M ethanol solution of the complexes were
measured at 25˚C by BC3020 Professional Bench top conductivity meter Trans instruments.
III. Results and Discussion
The physical properties of complexes are given in table 1 in addition to the molar conductance values
with 0.001M in ethanol as a solvent at room temperature 25 ˚C which indicating non electrolyte behavior.
Table 1: Physical data of mixed ligand complexes
Compound Formula and
name
Color and
m.p.
Metal analysis
Found (Calc.)
Molar
Conductivity
µs
Suggested
Structure
HQCo [Co(his.)(quin.)]
Histidinatoquinolino
cobalt(II)
Green
200 ˚C
15.5 (15.6) 3.21 Octahedral
HQNi [Ni(his.)(quin.)]
Histidinatoquinolino
nickelt(II)
Light green
280 ˚C
15.4 (15.5) 17.63 Octahedral
HQCu [Cu(his.)(quin.)]
Histidinatoquinolino
copper(II)
Dark green
290 ˚C
14.9 (15.8) 20.0 Octahedral
3.1 Ultraviolet-visible spectroscopy
The octahedral Co (II) is known to has the following three spin allowed transition (υ1) 4
T1g (F) → 4
T2g (F),
(υ2) 4
T1g (F) → 4
A2g (F) and (υ3) 4
T1g (F) → 4
T2g (P) out of these, the first transition (υ1) usually occurs lower
frequencies and is expected to appear beyond 1000 nm in the near infrared region. The position of (υ2) transition in Co
(II) complex, however be ambiguous and is rather difficult to locate with certainty sometimes it appears as a shoulder on
either side of the main absorption band (υ3 transition) or in some cases it may not be observed at all .[19]
Thus in the present
study of cobalt (II) complex, the transition obtained at 953 nm can be assigned as υ1 transition. The main absorption band
observed at 752 nm can be assigned as υ3 transition. The position of υ2 transition is not clear; other bands observed at
238,426 can be regarded as ligand field and charge transfer bands, respectively.
The band at 341 nm is typical ligand based transition. Ni(II) complex shows three bands with λ max value in the
range 410, 740- 767 nm and around 916 nm, these bands assigned to the respective d-d transitions, 3
A2g (F)→ 3
T1g (P),
3
A2g (F)→ 3
T1g (F), 3
A2g (F)→ 3
T2g (F) with Ni(II) ion the octahedral ligand field .[5]
The electronic spectrum of Cu (II) shows d-d transition at 680 nm {2
Eg →2
T2g (F) transition} is more consistent with
octahedral geometry .[5]
3.2 Infrared spectra of complexes
The characteristic vibrations modes of mixed ligand complexes are described in table 2. IR spectra of
HQCo (m.p 200 ˚C), HQNi (m.p 280 ˚C) and HQCu (290 ˚C) complexes show a broad band in the range of
3450-3435 cm-1
followed by another band in the range 800- 817 cm-1
,which is due to characteristic of υOH of
coordinated water. An important feature of infrared spectra of the metal complexes with Qui. is the absence of
O-H stretching vibration of the free phenol group O-H appear about 3150 cm-1
region. A presence of υ (C-O)
band at 1215 cm-1
in Qui. spectrum, shifting to the higher frequencies between 7-19 cm-1
in the spectrum of
3. Synthesis and Thermal Study of Co (II), Ni (II), Cu (II) Mixed Ligand Complexes Using Histidine…
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mixed ligand complexes, indicating the coordination of phenolic oxygen to metal ion.[10]
The υ(C꞊N) band
observed at 1575 cm-1
in the spectrum of Qui. ligand, this band reduced in intensity with shifting to lower wave
number1537 cm-1
in the spectra of complexes, this indicates the coordination through nitrogen donor of Qui.
with the metal .[13]
In amino acid υ NH3
+
appears in 3130-3030 cm-1
region .[20]
In the spectrum of His. it appears at 3082
cm-1
but overlaps with other vibrations such as υNH (imidazole group) and υCH (heterocyclic + υCH2 group ꞊
3016 cm-1
). Theoretically υ NH3
+
should vanish on coordination. In metal complexes, however, some broad
band appears at ꞊3300 cm-1
,which must be arising from other vibrations appearing in this region.[21]
In His.
spectrum in plane deformation δ (NH3
+
) appears at 1633 cm-1
which vanishs in metal complexes. The υasym
(COO-
) band of His. observed at 1633 cm-1
is shifted to lower wave number 1600-1625 cm-1
and the υsym
(COO-
) mode observed 1413 cm-1
in the spectrum of His. is found to be shifted to lower wave number 1377-
1380 cm-1
in the spectra of complexes indicating the coordination of carboxylic acid group via oxygen with
metal. The magnitude of separation between these two vibrations (<200 cm-1
) suggests that the coordination of
carboxylate group is in unidentate fashion .[10]
The imidazole exhibit a strong C꞊N ring band in the region
1581-1577 cm-1
which is shifted to 1535 cm-1
in all complexes. This lower value of imidazole υC꞊Nindicates
that imidazole nitrogen in coordination with the metal ion in all the complexes.[5]
The infrared of prepared
complexes have shown weak bands in the range of (430-474) cm-1
and (524- 576) cm-1
which was attributed to
the υ(M-O) and υ(M-N) respectively. [4, 13]
Table 2: The characteristic bands of infrared spectra of the mixed ligand complexes
3.3 Thermal studies
The TG and DTA studies of complexes have been recorded in the helium gas at the constant heating
rate of 20 ˚C/min. The complexes show gradual loss in weight due to decomposition by fragmentation with
increasing temperature. Thermogravimetric curve of HQCo, HQNi and HQCu complexes show the presence of
coordinated water and HQCu complex also show water molecule in outer of the coordination sphere.
Thermogram of these complexes shows the loss in weight corresponding to water molecules with
moiety of histidine , followed by weight loss of 8-hydroxyquinoline as well as CO2 moieties present in the
complexes.[10,5]
thermolysis data for complexes are given in table 3.
Table3: Thermolysis data for HQCo, HQNi and HQCu complexes.
NO. Complex Temperature
range ,˚C
٪Weight loss Decomposition product Liberate
partFound Calcd.
1.
[CoC15H16N4O4] 30-100 17.2 18.5 [CoC12H10N2O4] C3H6N2
140-240 5.5 7.9 [CoC11H8N2O3] H2O,C
300-400 31.7 34.2 [CoC2H2NO3] C9H6N
600-730 12.4 14.8 [CoONH2] CO2,C
2. [NiC15H16N4O4] 110-190 22.7 23.2 [NiC12H8N2O3] C3H6N2
H2O
230-300 6.2 6.3 [NiC10H8N2O3] C
315-500 33.1 34.2 [NiCH2NO3] C9H6N
530-700 13.8 15.8 [NiO] CO2 NH2
3. [CuC15H18N4O5] 100-150 23.2 24.7 [CuC11H13N2O4] H2O
C4H5N2
150-280 10.5 11.7 [CuC10H8NO3] H2O
CH3N
280-400 10.5 10.9 [CuC9H8NO] CO2
400-800 17.5 16.7 [CuC5H3N] C4H3O
IV. Conclusion
The evidences obtained from the above studies suggest an octahedral structure for HQCo, HQNi and
HQCu with tridentate histidine ligand and bidentate 8-hydroxyquinoline ligand. The molar conductivity of
Compound υ (O-H)
phenol
υ (C=N)
imine
υ (C-O)
phenol
υasym (COO-
) ,
υsym (COO-
)
υ (C=N)
imidazole υ (M-N)
υ (M-O)
Qui 3150 1575 1215 - - - -
His - - - 1633
1413
1581 - -
HQCo - 1537 1222 1625
1377
1535
528
440
HQNi - 1537 1234 1600
1379
1535
576 474
HQCu - 1537 1230 1600
1380
1535
524
430
4. Synthesis and Thermal Study of Co (II), Ni (II), Cu (II) Mixed Ligand Complexes Using Histidine…
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complexes has non- electrolytic nature of all complexes. Thermal analysis confirms the presence of a
coordinated water molecule in all prepared complexes and water molecule out of the coordination sphere of
HQCu complex.
H2
N
N O
M
O
OH2
N
H
O
N
X
M=Co(II),Ni(II) cobalt and nickel complexes
M=Cu(II),X=H2O copper complex
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