Phosphorus and Arsenic Atom Transfer to Isocyanides to Form π‐Backbonding Cyanophosphide and Cyanoarsenide Titanium Complexes
Anders Reinholdt, Mehrafshan G. Jafari, Christian Sandoval‐Pauker, Ernesto Ballestero‐Martínez, Michael R. Gau, Matthias Drieß, Balázs Pintér, Daniel J. Mindiola
Abstract
Abstract Decarbonylation along with E atom transfer from Na(OCE) (E=P, As) to an isocyanide coordinated to the tetrahedral Ti II complex [(Tp t Bu,Me )TiCl], yielded the [(Tp t Bu,Me )Ti(η 3 ‐ECNAd)] species (Ad=1‐adamantyl, Tp t Bu,Me− =hydrotris(3‐ tert ‐butyl‐5‐methylpyrazol‐1‐yl)borate). In the case of E=P, the cyanophosphide ligand displays nucleophilic reactivity toward Al(CH 3 ) 3 ; moreover, its bent geometry hints to a reduced Ad−NCP 3− resonance contributor. The analogous and rarer mono‐substituted cyanoarsenide ligand, Ad−NCAs 3− , shows the same unprecedented coordination mode but with shortening of the N=C bond. As opposed to Ti II , V II fails to promote P atom transfer to AdNC, yielding instead [(Tp t Bu,Me )V(OCP)(CNAd)]. Theoretical studies revealed the rare ECNAd moieties to be stabilized by π‐backbonding interactions with the former Ti II ion, and their assembly to most likely involve a concerted E atom transfer between Ti‐bound OCE − to AdNC ligands when studying the reaction coordinate for E=P.