The study reports a computational analysis of the influence of proton donor group adjacent to the reaction center during ester ammonolysis of an acylated diol as a model reaction for peptide bond formation. This analysis was performed using catalytic maps constructed after a detailed scanning of the available space around the reaction centers in different transition states, a water molecule acting as a typical proton donor. The calculations suggest that an adjacent proton donor center can reduce the activation barrier of the rate determining transition states by up to 7.2 kcal/mol, while no inhibition of the reaction can be achieved by such a group.
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http://dx.doi.org/10.1016/j.jmgm.2011.05.004 | DOI Listing |
Small Methods
January 2025
State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide & Agricultural Bioengineering, Ministry of Education, State-Local Joint Laboratory for Comprehensive Utilization of Biomass, Center for R&D of Fine Chemicals, Guizhou University, Guiyang, Guizhou, 550025, China.
Photocatalytic transfer hydrogenation of biomass-derived aldehydes to alcohols often results in unwanted coupling co-products. Herein, an ultraselective hydrogen transfer system enabled by in situ oxidative C─C bond cleavage over a Janus single-atom palladium on titanium dioxide (0.5Pd/TiO) photocatalyst is presented.
View Article and Find Full Text PDFChemistry
January 2025
Indian Institute of Technology Delhi, Department of Chemistry, Hauz Khas, 110016, New Delhi, INDIA.
A mononuclear CoIII complex (1) of a bisamide-bisalkoxide donor ligand was synthesized and thoroughly characterized. The reaction of 1 with 0.5 equiv.
View Article and Find Full Text PDFEur J Inorg Chem
May 2024
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Lytic polysaccharide monooxygenases (LPMOs) are Cu-dependent metalloenzymes that catalyze the hydroxylation of strong C-H bonds in polysaccharides using O or HO as oxidants (monooxygenase/peroxygenase). In the absence of C-H substrate, LPMOs reduce O to HO (oxidase) and HO to HO (peroxidase) using proton/electron donors. This rich oxidative reactivity is promoted by a mononuclear Cu center in which some of the amino acid residues surrounding the metal might can accept and donate protons and/or electrons during O and HO reduction.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Faculty of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan.
The factors controlling the catalytic activity in photochemical hydrogen evolution reaction (HER) are studied in detail for two macrocyclic cobalt compounds bearing two N-heterocyclic carbenes and two pyridyl donors ( and , where has a methoxy substituent on each pyridyl ligand). The present study adopts an aqueous photosystem consisting of EDTA, [Ru(bpy)] (bpy = 2,2'-bipyridine), and MV (MV = methylviologen) at pH = 5. Both catalysts are shown to promote HER in a similar efficiency (TON = 12-13 in 6 h), revealing a minor contribution of the electron-donating methoxy substituents.
View Article and Find Full Text PDFMolecules
December 2024
Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Wanstead P.O. Box 64, Barbados.
A computational study of X-H···Y binary hydrogen-bonded complexes was undertaken to examine the red- and blue-shifting behavior of three model X-H proton donors interacting with a series of Lewis bases: Y = NH, NCLi, NCH, NCF, CH, BF, CO, N and Ne. Two of these proton donors, FArH and FCH, have blue-shifting tendencies, while the third, FH, has red-shifting tendencies. A perturbation theory model for frequency shifts that was derived many years ago was employed to partition the predicted frequency shift into the sum of two components, one dependent on the second derivative of the interaction energy with respect to X-H displacement and the other dependent on the X-H bond length change in the binary complex.
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