Enhanced π‐Backdonation from Gold(I): Isolation of Original Carbonyl and Carbene Complexes

Abstract

The specific electronic properties of bent o-carborane diphosphine gold(I) fragments were exploited to obtain the first classical carbonyl complex of gold [(DPCb)AuCO](+) (ν(CO)=2143 cm(-1) ) and the diphenylcarbene complex [(DPCb)Au(CPh2 )](+) , which is stabilized by the gold fragment rather than the carbene substituents. These two complexes were characterized by spectroscopic and crystallographic means. The [(DPCb)Au](+) fragment plays a major role in their stability, as substantiated by DFT calculations. The bending induced by the diphosphine ligand substantially enhances π-backdonation and thereby allows the isolation of carbonyl and carbene complexes featuring significant π-bond character.

Gold(I) Vinylidene Complexes as Reactive Intermediates and Their Tendency to π‐Backbond

“…We quantify the interaction as the fraction of electrons of the doubly occupied orbital assigned to the individual atoms. The π‐backbonding exceeds what we previously computed for the bidentate phosphine ligand with a carborane backbone Au(CPh 2 ) complex reported by Bourissou and co‐workers (0.174) . A comparison to the carbonyl complexes 5 and 6 highlights one important aspect, the ability of the CO ligand to readily receive π‐backdonation in two perpendicular planes with the two π* antibonding orbitals.…”

A Nucleophilic Gold(III) Carbene Complex

“…[1] Thevery nature of the AuÀC carbene bond has also attracted considerable attention. Accordingly, p donation from the carbene substituents [4][5][6] or enhanced p backdonation from the Au center, [7] were recently distinguished as the main stabilization modes of the electrophilic carbene center ( Figure 1). Accordingly, p donation from the carbene substituents [4][5][6] or enhanced p backdonation from the Au center, [7] were recently distinguished as the main stabilization modes of the electrophilic carbene center ( Figure 1).…”

Copper and Silver Carbene Complexes without Heteroatom‐Stabilization: Structure, Spectroscopy, and Relativistic Effects

“…Interestingly,i midophosphamidato and b-diketiminato copper carbene complexes [25] and ab isphosphane gold carbene complex [26] of the d 10 [25d] )t han the copper complex 2 Cu (d = 332.0 ppm) with its positive charge and its lower coordination number at copper. Theidentity of the Group 11 element, its coordination number,t he nature and the charge of the ancillary ligand, and the p-donor strength of the carbene'ss ubstituents determine reactivity, stability,and the spectral properties of carbene complexes.…”