Essential to biological activity of adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) is the Co-C bond cleavage step. Hence, we report an accurate determination of the homolytic gas-phase Co-C bond dissociation energies in the related adenosyl- and methylcobinamides (41.5 ± 1.2 and 44.6 ± 0.8 kcal/mol, respectively) utilizing an energy-resolved threshold collision-induced dissociation technique. This approach allows for benchmarking of electronic structure methods separate from (often ill-defined) solvent effects. Adequacy of various density functional theory methods has been tested with respect to the experimentally obtained values.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ja406676p | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Tailoring the Porous Structure of Carbon for Enhanced Oxidative Cleavage and Esterification of C(CO)-C Bonds.
ChemSusChem
December 2024
National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China.
The cleavage and functionalization of carbon-carbon bonds are crucial for the reconstruction and upgrading of organic matrices, particularly in the valorization of biomass, plastics, and fossil resources. However, the inherent kinetic inertness and thermodynamic stability of C-C σ bonds make this process challenging. Herein, we fabricated a glucose-derived defect-rich hierarchical porous carbon as a heterogeneous catalyst for the oxidative cleavage and esterification of C(CO)-C bonds.
View Article and Find Full Text PDFSpectroscopic and Computational Insights into the Mechanism of Cofactor Cobalt-Carbon Bond Homolysis by the Adenosylcobalamin-Dependent Enzyme Ethanolamine Ammonia-Lyase.
J Am Chem Soc
January 2025
Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
The adenosylcobalamin (AdoCbl)-dependent enzyme ethanolamine ammonia-lyase (EAL) catalyzes the conversion of ethanolamine to acetaldehyde and ammonia. As is the case for all AdoCbl-dependent isomerases, the catalytic cycle of EAL is initiated by homolytic cleavage of the cofactor's Co-C bond, producing Cocobalamin (CoCbl) and an adenosyl radical that serves to abstract a hydrogen atom from the substrate. Remarkably, in the presence of substrate, the rate of Co-C bond homolysis of enzyme-bound AdoCbl is increased by 12 orders of magnitude.
View Article and Find Full Text PDFCrystal structure of -poly[[di-aqua-di-imida-zole-cobalt(II)]-μ-2,3,5,6-tetra-bromo-benzene-1,4-di-carboxyl-ato].
Acta Crystallogr E Crystallogr Commun
October 2024
Toyota Central R&D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan.
The asymmetric unit of the title compound, [Co(CBrO)(CHN)(HO)] or [Co(Brbdc)(im)(HO)] , comprises half of Co ion, tetra-bromo-benzene-dicarboxylate (Brbdc), imidazole (im) and a water mol-ecule. The Co ion exhibits a six-coordinated octa-hedral geometry with two oxygen atoms of the Brbdc ligand, two oxygen atoms of the water mol-ecules, and two nitro-gen atoms of the im ligands. The carboxyl-ate group is nearly perpendicular to the benzene ring and shows monodentate coordination to the Co ion.
View Article and Find Full Text PDFHydrogen tunneling with an atypically small KIE measured in the mediated decomposition of the Co(CHCOOH) complex.
Phys Chem Chem Phys
November 2024
Baylor University, 1311 S 5th St, Waco, TX 76706, USA.
Quantum mechanical tunneling (QMT) is a well-documented phenomenon in the C-H bond activation mechanism and is commonly identified by large KIE values. Herein we present surprising findings in the kinetic study of hydrogen tunneling in the Co mediated decomposition of acetic acid and its perdeuterated isotopologue, conducted with the energy resolved single photon initiated dissociative rearrangement reaction (SPIDRR) technique. Following laser activation, the reaction proceeds along parallel product channels Co(CHO) + CO and Co(CHO) + HO.
View Article and Find Full Text PDFFacile preparation of NiFeO decorated chitosan-graphene oxide for efficient remediation of Co(II) and adsorption mechanism.
Int J Biol Macromol
November 2024
College of Material Science and Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, PR China.
In the background of severe water pollution, adsorption is a charming technique for heavy metal remediation. In this work, NiFeO decorated chitosan-graphene oxide (NFCG) was prepared by simple hydrothermal method for Co(II) remediation application. Adsorption mechanism was elaborately elucidated based on multiple evidences extracted from adsorption fitting (isotherms, thermodynamics and kinetics), spectroscopic test (XPS, UV-Vis absorption, fluorescent emission and Raman spectra) and the hard-soft acid-base (HSAB) theory inspection.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!