DFT calculations bring insight to internal alkyne-to-vinylidene transformations at rhodium PNP- and PONOP-pincer complexes.

ABSTRACT: Density Functional Theory (DFT) has been used to investigate the alkyne-to-vinylidene isomerisation reaction mediated by [Rh(PXNXP)]⁺ complexes (X = CH₂: 2,6-bis(di-tert-butylphosphinomethyl)pyridine (PNP) and X = O: 2,6-bis(di-tert-butylphosphinito)pyridine (PONOP)) for terminal alkynes HC[triple bond, length as m-dash]CR, where R = ^t Bu and Ar' (3,5- ^t Bu₂C₆H₃). Calculations suggest the reaction mechanism proceeds via the slippage of π-bound alkyne at the Rh centre into a Rh-alkyne σ_C-H complex followed by an indirect 1,2-H shift to give the Rh-vinylidene species. NBO (Natural Bond Orbital) analysis of the transition states corresponding to the latter indirect 1,2-H

SUBMITTER: Rajabi NA 

PROVIDER: S-EPMC8696595 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature