15N AND 31P NMR STUDIES OF CYANO(TRIALKYL/TRIARYL)PHOSPHINE GOLD(I) COMPLEXES

The ligand scrambling reaction of R 3 PAuC 15 N to form (R 3 P) 2 Au + and Au(C 15 N) 2 − has been studied (by 15 N and 31 P NMR spectroscopy) for R = Me, Et, i-Pr, and Ph. 31 P NMR showed two resonances due to R 3 PAuCN and (R 3 P) 2 Au + species, while 15 N NMR showed only an averaged resonance due to R 3 PAuC 15 N and Au(C 15 N) 2 − species, except for Et 3 PAuC 15 N, for which two separate resonances were detected. R 3 PAu 13 C 15 N (where R = Me, Et and Ph) complexes were also prepared and 2 J( 31 P- 13 C) as well as 3 J( 31 P- 15 N) constants were measured. The free activation energy for ligand scrambling in Ph 3 PAuCN was determined by 31 P NMR band shape analysis to be 39.7 kJ/mol −1 .