Comparing Protonolysis and Transmetalation Reactions: Microcalorimetric Studies of C–AuI Bonds in [AuRL] Complexes

Abstract

The protonolysis of C–Au bonds in [AuRL] organometallic complexes has been studied by calorimetry for twelve R groups. The experimental data have been combined with DFT calculations to obtain Bond Dissociation Energy values (BDE). The C–Au BDE values show a good correlation with the corresponding isolobal C–H BDE values. The heat released in the protonolysis of [AuRL] has also been measured for R = Ph and L = P(OPh)3, PPh3, PMe3, PCy3, and IPr, and these values strongly depend on the trans influence of L because of the mutual destabilization of the L–Au and Au–C bonds. The enthalpy of the transmetalation reactions [AuR(PPh3)] + SnIBu3 → [AuI(PPh3)] + SnRBu3 for seven R groups have been measured and compared with the corresponding [AuR(PPh3)] protonolysis.