This research aims to develop new copper photocatalysts for asymmetric photoredox reactions as a more sustainable alternative to ruthenium complexes. The researchers synthesized a chiral catalyst and several copper complexes to act as photocatalysts in the α-alkylation of aldehydes. Their initial studies showed dichloromethane to be the most effective solvent, achieving a maximum yield of 75% under optimized conditions. Going forward, they plan to further explore the scope of compatible substrates and determine enantiomeric excess using HPLC, with the long-term goal of applying this methodology to synthesize biologically active natural products.
A 1,3-dipolar cycloaddition is a fascinating and diverse reaction that can be used in stepwise syntheses of large molecules, such as masked aldol reactions, and has potential biological applications. While it is an incredibly useful reactions, is also has a simple mechanism.
Contributed by: Created by Alexandra Kent and Judy Zhu (Undergraduates)Edited by Margaret Hilton
Honors Organic Chemistry
University of Utah
Bio-Molecular Engineering is the Future of Molecular BiologyBob Eisenberg
Bio-Molecular Engineering is the Future of Molecular Biology: Now that we have large numbers of excellent structures, we molecular biologists must turn to studying how they work. That is the task of BioMolecular Engineering that uses almost the same tools as classical membrane biophysics. Both treat systems as devices, with inputs, outputs and power supplies, that ONLY function with flow, away from equilibrium.
Another productive school presentation. Again, it contains mostly icons or pictures since when i do reporting, words come out either directly from my mouth or from the participants. it will be easy if you read super duper much first before you consider this presentation. BTW, i called it, ENERGY UTILIZATION.
Happy days are coming your life!!!
A 1,3-dipolar cycloaddition is a fascinating and diverse reaction that can be used in stepwise syntheses of large molecules, such as masked aldol reactions, and has potential biological applications. While it is an incredibly useful reactions, is also has a simple mechanism.
Contributed by: Created by Alexandra Kent and Judy Zhu (Undergraduates)Edited by Margaret Hilton
Honors Organic Chemistry
University of Utah
Bio-Molecular Engineering is the Future of Molecular BiologyBob Eisenberg
Bio-Molecular Engineering is the Future of Molecular Biology: Now that we have large numbers of excellent structures, we molecular biologists must turn to studying how they work. That is the task of BioMolecular Engineering that uses almost the same tools as classical membrane biophysics. Both treat systems as devices, with inputs, outputs and power supplies, that ONLY function with flow, away from equilibrium.
Another productive school presentation. Again, it contains mostly icons or pictures since when i do reporting, words come out either directly from my mouth or from the participants. it will be easy if you read super duper much first before you consider this presentation. BTW, i called it, ENERGY UTILIZATION.
Happy days are coming your life!!!
A coupling reaction in organic chemistry is a general term for a variety of reactions where two hydrocarbon fragments are coupled with the aid of a metal catalyst.
* Adenosine triphosphate (ATP) is energy currency in our body.
*ATP contains
1.A nitrogenous base – Adenine
2.A sugar – Ribose
3.Three Phosphate Groups
*Whenever a body needs energy beta – gamma phosphate bonds of ATP is hydrolyzed to create the ADP and a free phosphate molecule.
*ATP forms by the processes – Citric acid cycle and Glycolysis.
Los días 11 y 12 de diciembre de 2014, la Fundación Ramón Areces celebró el Simposio Internacional 'Neuropatías periféricas hereditarias. Desde la biología a la terapéutica' en colaboración con CIBERER-ISCIII y el Centro de Investigación Príncipe Felipe. El tipo más común de estas patologías es la enfermedad de Charcot-Marie-Tooth, un trastorno neuromuscular hereditario con una prevalencia estimada de 17-40 afectados por 100.000 habitantes. Durante estos dos días, investigadores mostraron sus avances en la mejora del diagnóstico y el tratamiento y, por ende, de la aproximación clínica y la calidad de vida de las personas afectadas por estas patologías.
Según estudios internacionales, está probado que la depresión es una enfermedad que llega a afectar a una de cada cinco o seis personas a lo largo de su vida. Por este motivo, el 14 de junio de 2016 dedicamos una jornada a 'La prevención y el abordaje de la depresión en el ámbito laboral'. Estuvo organizada en colaboración con la Fundación Española de Psiquiatría y Salud Mental (FEPSM).
Los días 8 y 9 de octubre de 2014, la Fundación Ramón Areces acogió el Simposio Internacional 'Química: respuestas para una vida mejor', organizado en colaboración con la Fundación General CSIC. Su finalidad fue ofrecer a los participantes una visión atractiva de la química moderna que sirva de base al desarrollo de nuevas respuestas para una sociedad en rápida evolución.
A coupling reaction in organic chemistry is a general term for a variety of reactions where two hydrocarbon fragments are coupled with the aid of a metal catalyst.
* Adenosine triphosphate (ATP) is energy currency in our body.
*ATP contains
1.A nitrogenous base – Adenine
2.A sugar – Ribose
3.Three Phosphate Groups
*Whenever a body needs energy beta – gamma phosphate bonds of ATP is hydrolyzed to create the ADP and a free phosphate molecule.
*ATP forms by the processes – Citric acid cycle and Glycolysis.
Los días 11 y 12 de diciembre de 2014, la Fundación Ramón Areces celebró el Simposio Internacional 'Neuropatías periféricas hereditarias. Desde la biología a la terapéutica' en colaboración con CIBERER-ISCIII y el Centro de Investigación Príncipe Felipe. El tipo más común de estas patologías es la enfermedad de Charcot-Marie-Tooth, un trastorno neuromuscular hereditario con una prevalencia estimada de 17-40 afectados por 100.000 habitantes. Durante estos dos días, investigadores mostraron sus avances en la mejora del diagnóstico y el tratamiento y, por ende, de la aproximación clínica y la calidad de vida de las personas afectadas por estas patologías.
Según estudios internacionales, está probado que la depresión es una enfermedad que llega a afectar a una de cada cinco o seis personas a lo largo de su vida. Por este motivo, el 14 de junio de 2016 dedicamos una jornada a 'La prevención y el abordaje de la depresión en el ámbito laboral'. Estuvo organizada en colaboración con la Fundación Española de Psiquiatría y Salud Mental (FEPSM).
Los días 8 y 9 de octubre de 2014, la Fundación Ramón Areces acogió el Simposio Internacional 'Química: respuestas para una vida mejor', organizado en colaboración con la Fundación General CSIC. Su finalidad fue ofrecer a los participantes una visión atractiva de la química moderna que sirva de base al desarrollo de nuevas respuestas para una sociedad en rápida evolución.
Use of stoichiometric amounts of a chiral source. The usual suspects will be discussed, including borane reagents (mostly pinene derivatives) and the Brown allylation.
The big topic of the last few years, the use of small organic molecules to catalyse enantioselective transformations. This lecture will start with proline before moving on to some of MacMillan's contributions to this field and, finally, finish with hydrogen bond catalysts and Brønsted acids.
What is catalysis, its type and its applicationLovnish Thakur
This document will give you information about catalysis and type of catalysis like homogenious and heterogenious catalysis and its various application .
RAPID IODINATION OF THE ISOMERS OF AMINOBENZOIC ACID IN AQUEOUS MEDIUM BY IOD...EDITOR IJCRCPS
The rapid kinetics of the iodination of para-aminobenzoic acid and meta-aminobenzoic acid by iodine monochloride at 4.5 pH has
been studied by employing hydrodynamic voltammetry. The reactions were found to be of the second order and the specific
reaction rates for the two reactions were found to be 25 M-1s-1 and 10 M-1s-1 at 25.00C respectively. These data were
complemented with those for the iodination of ortho-aminobenzoic acid by ICl obtained earlier to quantitatively assess the relative
reactivity of the three isomers stemming from substituent regiospecificity.
Keywords: Iodine monochloride, hydrodynamic voltammetry, aminobenzoic acid isomers.
Quantum yield, experimental arrangement, reasons for high and low Quantum yield, problems, photochemical reactions, kinetics of photochemical decomposition of HI, photosensitized reaction, mechanism of photosensitization,
Light-Induced Controlled Free Radical Polymerization of Methacrylates Using I...Pawan Kumar
A novel visible light mediated catalytic system
based on low cost iron complex, that is, Fe(bpy)3(PF)6 photocatalyst
that initiates and control the free radical polymerization
of methacrylates using ethyl a-bromoisobutyrate (EBriB) as an
initiator and 20 watt LED as light source is developed. The
polymerization is initiated with turning the light on and immediately
terminated by turning the light off. In addition, the
molecular weight of polymer can be varied by changing the
ratio of monomer and initiator. The merits of the present methodology
lie in the use of low cost less precious, highly abundant
iron-based photocatalyst, avoidance of sacrificial donor
and need of lower catalyst amount under visible light. The
optimum amount of catalyst and initiator were established and
successful polymerization of various methacrylates was
achieved under the optimized polymerization conditions.
Antibacterial Application of Novel Mixed-Ligand Dithiocarbamate Complexes of ...IOSR Journals
Nine stable mixed ligand dithiocarbamate complexes of Nickel (II) ion were prepared. The complexes were characterized with electronic spectroscopy, infrared spectroscopy, conductance measurement, melting point and percentage metal analysis. Resulting analytical data gave credence to the assignment of a tentative square planar geometry to all the complexes. The complexes were proposed to have a general formulae of [Ni(Sal)(Rdtc)], where Sal = salicylaldehyde; R = dibenzylamine(Bz2NH), methylphenylamine(MePhNH),pyrrolidineamine(pyrrolNH),piperidineamine(piperNH),morpholineamine(MorpNH), anilineamine(AnilNH), para-chloroanilineamine(p-ClAnilNH), toludineamine(TolNH) and anisidineamine(AnisNH); and dtc = dithiocarbamate anion. The metal complexes were screened against six different bacteria strain using Agar diffusion method. The antibacterial studies reveal that the metal complexes exhibit broad spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella oxytoca and Pseudomonas aureginosa with inhibitory range of 10.5.—20.0mm.
1. Michael R. Hurst, Cassidy L. Kotelman, and Katrina H. Jensen
Black Hills State University
1200 University Street, Spearfish, SD 57799
Katrina.Jensen@bhsu.edu
I. Introduction III. Catalytic Cycle V. Photocatalyst Synthesis
VIII. Future Research
Evaluation of Copper Photocatalysts in the Enantioselective α–Alkylation of Aldehydes
Catalysts act to increase the rate of reactions by lowering the
activation energy required to initiate a reaction. We are
working towards developing new reactions using a chiral
catalyst and a photoredox catalyst with the end goal of
synthesizing small molecules.
In photoredox catalysis, light energy is absorbed by a
catalyst, moving the catalyst into an excited state. From this
high energy level, it can then donate or accept an electron
from organic reagents. The resulting molecule is a highly
reactive radical intermediate.
light
Energy
photo-
excitation
Ground State Excited State
oxidation
– e–
Oxidized State
II. Background and Significance
In our research, we are attempting to develop copper
catalysts for photoredox reactions. Currently, reported
photoredox reactions1 use ruthenium and iridium
complexes; however, copper would make for a more
sustainable alternative as it is earth-abundant, nontoxic, and
relatively inexpensive. Furthermore, bisphenanthroline
copper complexes2 are known with similar photophysical
properties as Ru(bpy)3
2+.
Cost per ounce:
Ruthenium: $56.00
Copper: $0.18
Abundance in Earth’s crust:
Ruthenium: 0.000000099%
Copper: 0.0068%
1J. W. Tucker, C. R. J. Stephenson J. Org. Chem. 2012, 77, 1617-1622
2D. V. Scaltrito, D. W. Thompson, J. A. O’Callaghan, G. J. Meyer Coord. Chem. Rev. 2000,
208, 243-266
In general, photoredox catalysis shows great potential in
many chemical applications due to its low energy
requirement. Instead of relying on the energy of other
mechanical or chemical sources, this reaction methodology
only necessitates the light of a standard lightbulb, reducing
costs and boosting efficiency.
One specific application of photoredox catalysis is in the
synthesis of small molecules, which are being used in the
improvement and utilization of disease treatments.
In the following catalytic cycle, on which we have chosen to
focus,3 both a chiral catalyst and a photocatalyst are involved in
the reaction. These species act together in dual catalytic cycles.
3D. A. Nicewicz, D. W. C. MacMillan Science 2008, 322, 77-80
IV. Chiral Catalyst Synthesis
10% yield62% yield
9% yield 2% yield
We examined photoredox catalysts in Reaction A, shown here:
A chiral catalyst provides facial selectivity in our asymmetric
photoredox reaction. We synthesized our desired chiral
catalyst, 2, in four steps, beginning from molecule 1.
Shown below is the synthesis of 2.
Chiral Catalyst Synthesis4:
4T. H. Graham, B. D. Horning, D. W. C MacMillan, Org. Synth., 2011, 88, 42-53.
VI. Exploring Copper Photocatalysts
A
D
F
BE
C
1H NMR
IX. Acknowledgements
Research team: (back)
(front)
Dr. Katrina Jensen, Michael Hurst, Cassidy Kotelman
Alissa Iverson, Thomas Trimble, and Sarah Souder
Research reported in this publication was supported by an Institutional Development Award (IDeA) from the
National Institute of General Medical Sciences of the National Institutes of Health under grant number
P20GM103443. The content is solely the responsibility of the authors and does not necessarily represent the
official views of the National Institutes of Health. Acknowledgement is also made to the donors of the
American Chemical Society Petroleum Research Fund for support of this research
Photoredox Catalysts:
• Short term goals
- Continue to optimize the reaction conditions,
evaluating factors such as light source, solvent
system, scale, and ratio of each reactant.
- Evaluate the scope of the reaction by evaluating
other aldehyde and α-bromocarbonyl pairs as
reaction partners.
- Determine enantiomeric excess of reaction with
high pressure liquid chromatography (HPLC).
• Long term goals
- Use the developed reaction methodology to target
natural products and other molecules for
synthesis. These would include biologically active
molecules offering medicinal benefits such as
antimicrobial activity.
A photocatalyst interacts with light to catalyze a reaction. We
synthesized a number of a copper complexes with this
property. Shown below is the synthesis of Cu(dap)2Cl.
Photocatalyst Synthesis:
1H NMR
VII. Changing Solvent Systems
Using Cu(dap)2Cl in Reaction A, we tested several solvent
systems in order to improve percent yield.
Solvent Percent Yield
DMF 9%
CH2Cl2 62%
MeCN 10%
DMSO 55%
CHCl3 17%
Toluene 18%
Benzene 24%
THF 19%
EtOAc 29%
Et2O 71%
Dichloroethane 18%
TBME 72%
Chlorobenzene 42%
After identifying CH2Cl2 as
our most viable solvent, we
further altered percent yield
by increasing concentration
of the reactants.
mL CH2Cl2 Percent Yield
0.8 62%
0.6 41%
0.4 45%
0.2 66%
0.0 75%
Percent yields were measured using
gas chromatography with an internal
standard (tetradecane). The percent
yields were evaluated between t=18
and t=22 hours.
Reaction Conditions: 0.800 mL of solvent, 0.800 mmol octaldehyde, 0.400 mmol
diethylbromomalonate, 0.080 mmol chiral catalyst, 0.004 mmol photocatalyst,
0.800 mmol 2,6-lutidine, and 0.080 mmol tetradecane.
Reaction A is prepared
by mixing a standard
solution with our photo
catalyst and chiral
catalyst, then placing
mixture within 3 cm of a
26 watt light source for
~18 hours
A B C CD3OD D E F
1H NMR
1 91% yield 95% yield
91% yield 2 48% yield
A B C D E F
A
B
C
D
F
E
+
A CDCl3 B C D E E’ F G
A
B
C
D
F
G
F
In this mechanism, the chiral catalyst works to properly orient
a reactant molecule and to make it more reactive. This allows a
free radical to attach, forming an enantiomer. In photoredox
reactions involving Ru(bpy)3, this free radical is the result of
reductive quenching.
Our research has focused on using Cu(phen’)2 complexes in
place of Ru(bpy)3. We propose that this will yield a free radical
through oxidation, still effectively enabling the overall reaction.