NMR "Finger Prints" of N-Heterocyclic Carbenes, DFT Analysis: Scopes and Limitations.

ABSTRACT: The scopes and limitations of theoretical methods for estimating various NMR metrics of NHCs are considered on a wide range of model NHCs and their derivatives, using a number of computational approximations. On the whole, the most reliable, from the point of view of predictability and insusceptibility to additional effects, are 31P/13C NMR shifts of NHC-phosphinidene adducts and 13C CSs of carbenes themselves. The method based on the analysis of 77Se CS NHC-selenoureas has some limitations since the observed NMR parameters can also be modulated by exchange effects due to their formation with non-classical hydrogen bonds. As for HEP, since the delicate balance of electron distribution between Pd and two carbon centers can nonlinearly affect relativistic spin-orbit effects, the accuracy of

SUBMITTER: Kondrashova SA 

PROVIDER: S-EPMC10707865 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature