Aurolysis of α-C-deprotonated group 6 aminocarbene and thiocarbene complexes with Ph3PAu+

Deprotonated Fischer-type aminocarbene complexes, (CO)5MC(NR2)CH3 (M = Cr or W; R = Me or propyl), react with Ph3PAu+ by metal group substitution – (CO)5M for Ph3PAu+ – and attachment of the extricated M(CO)5 to the deprotonated methyl group. (The products may also be seen as aminovinylgold compounds coordinated to M(CO)5 moieties.) DFT calculations at the B3LYP level of theory using model compounds indicate a clear preference of the gold unit for central C to terminal coordination in the ligand [NMe2CCH2]−, whereas the Cr(CO)5 has a 7 kcal mol−1 preference for C(vinyl) coordination compared to N-coordination. In related thiocarbenes, the sulfur donor atom should be the preferred point of attachment for the metal carbonyl unit. The latter prediction is borne out in practice, and in the three products isolated, including Ph3PAu{C(CH2)SPh}Cr(CO)5 in a mixed crystal with [Ph3PAuSPh]Cr(CO)5, precisely this coordination mode is present. The latter component of the mixed crystal has also been prepared independently of the vinyl one.