The bond dissociation energies (BDEs) and radical stabilization energies (RSEs) which result from 166 reactions that lead to carbon-centered radicals of the type ˙CH(2)X, ˙CHXY and ˙CXYZ, where X, Y and Z are any of the fourteen substituents H, F, Cl, NH(2), OH, SH, CH[double bond, length as m-dash]CH(2), C[triple bond, length as m-dash]CH, BH(2), CHO, COOH, CN, CH(3), and CF(3), were calculated using spin-restricted and -unrestricted variants of the double-hybrid B2-PLYP method with the 6-311+G(3df,2p) basis set. The interactions of substituents X, Y, and Z in both the radicals (˙CXYZ) and in the precursor closed-shell molecules (CHXYZ), as well as the extent of additivity of such interactions, were investigated by calculating radical interaction energies (RIEs), molecule interaction energies (MIEs), and deviations from additivity of RSEs (DARSEs) for a set of 152 reactions that lead to di- (˙CHXY) and tri- (˙CXYZ) substituted carbon-centered radicals. The pairwise quantities describing the effects of pairs of substituents in trisubstituted systems, namely pairwise MIEs (PMIEs), pairwise RIEs (PRIEs) and deviations from pairwise additivity of RSEs (DPARSEs), were also calculated for the set of 61 reactions that lead to trisubstituted radicals (˙CXYZ). Both ROB2-PLYP and UB2-PLYP were found to perform quite well in predicting the quantities related to the stabilities of carbon-centered radicals when compared with available experimental data and with the results obtained from the high-level composite method G3X(MP2)-RAD. Particular selections of substituents or combinations of substituents from the current test set were found to lead to specially stable radicals, increasing the RSEs to a maximum of +68.2 kJ mol(-1) for monosubstituted radicals ˙CH(2)X (X = CH[double bond, length as m-dash]CH(2)), +131.7 kJ mol(-1) for disubstituted radicals ˙CHXY (X = NH(2), Y = CHO), and +177.1 kJ mol(-1) for trisubstituted radicals ˙CXYZ (X = NH2, Y = Z = CHO).
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c1ob05196b | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Visible-Light-Mediated Deaminative Alkylation of Primary Amines with Silacarboxylic Acids via Isonitrile Formation.
Org Lett
January 2025
Organic Chemistry Department, Faculty of Science, Autonomous University of Madrid, 28049 Madrid, Spain.
The functionalization of the C-N bond of amines is a straightforward strategy for the construction of complex scaffolds or for the late-stage functionalization of pharmaceuticals. Herein, we describe a photoredox-catalyzed strategy for the deaminative alkylation of primary amine-derived isonitriles that provides unnatural amino acid derivatives under mild conditions. The use of silacarboxylic acids as silyl radical precursors enables the generation of carbon-centered radicals that allow the construction of Csp-Csp bonds via a Giese-type addition, avoiding the undesired hydrodeamination product.
View Article and Find Full Text PDFCarbon-Centered Reactivity in Carbodiphosphorane-Based Ligands Allowing for Redox-Non-Innocent Ligand/Ligand Dual Bond-Activation.
Angew Chem Int Ed Engl
January 2025
Martin-Luther-Universitat Halle-Wittenberg, Department of Chemistry, Kurt-Mothes-Str. 2, 06120, Halle, GERMANY.
A pronounced nucleophilicity in combination with a distinct redox non-innocence is a unique feature of a coordinated ligand, which in the current case, leads to unprecedented carbon-centered reactivity patterns: A carbodiphosphorane-based (CDP) pincer-type rhodium complex allows to cleave two C-Cl-bonds of geminal dichlorides via two consecutive SN2-type oxidative additions resulting in the formation of a stabilized carbene fragment. In the presence of a suitable reductant the carbene fragment can even be converted into olefines or hydrodehalogenation products in a catalytic reaction. The developed method can also be used to convert chlorofluorocarbons (CFCs) such as CH2ClF to fluoromethane and methane.
View Article and Find Full Text PDFModification of iron-containing silicate tailings with oxalic acid to develop a long-efficacy utilization peroxymonosulfate-based system for the efficient decomplexation and removal of Cr(III)-ethylenediamine tetraacetic acid.
J Colloid Interface Sci
December 2024
Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
Ferrous oxalate (FeCO)-based composite has been recognized as an eminent catalyst for Cr(III)-ethylenediamine tetraacetic acid (Cr(III)-EDTA) decomplexation. However, their practical application has been limited by low cycling capacity and an ambiguous mechanism. In this research, a composite catalyst consisting of biotite loaded with nano FeCO (CFS90) was prepared directly from iron-containing silicate tailing.
View Article and Find Full Text PDFElectron transfer tuning for persulfate activation via the radical and non-radical pathways with biochar mediator.
J Hazard Mater
December 2024
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology), Chengdu, Sichuan 610059, P.R. China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, P.R. China. Electronic address:
Electron mediator-based in-situ chemical oxidation (ISCO) offers a novel strategy for groundwater remediation due to diverse reaction pathways. However, distinguishing and further tuning the reaction pathway remains challenging. Herein, biochar as an electron mediator targeted active peroxysulphate (PDS) via the radical or non-radical pathway.
View Article and Find Full Text PDFThrough Space π-Electrons Communication in [2,2]-Paracyclophanes: Unprecendented Stabilization of Radicals.
Angew Chem Int Ed Engl
December 2024
Aix Marseille Univ, CNRS, ICR UMR 7273, 13013, Marseille, France.
Efforts to understand radical stability have led to considerable progress in radical chemistry. In this article, we investigated a novel approach to enhancing the radical stability of carbon-centered radicals through space electron delocalization within [2,2]-paracyclophanes. Alkoxyamines possessing a paracyclophane scaffold exploit face-to-face π-π-interactions between the aromatic rings to effectively lower bond dissociation energy (BDE) for NO-C bond homolysis.
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!