Tuning the Lewis acidity of difluorido gold() complexes: the synthesis of [AuClF(SIMes)] and [AuF(OTeF)(SIMes)]

The synthesis and structural characterisation of the difluorido organo gold( iii ) complexes [AuClF 2 (SIMes)] and [AuF 2 (OTeF 5 )(SIMes)] are presented. The substitution of a fluorido ligand in [AuF 3 (SIMes)] by an OTeF 5 group increases the Lewis acidity of the Au moiety. A scale for carbene affinities is presented, which correlates calculated and experimental values for the Lewis acidity of the metal centre in akin compounds. A route to [Au III ClF 2 (SIMes)] and [Au III F 2 (OTeF 5 )(SIMes)] including structural characterization to tune the ligand arrangement and Lewis acidity of gold( iii ) centres was developed.