Vibrational and solid state (CP/MAS) P-31 NMR spectroscopic studies of bis(trimethylphosphine)gold(I) halides

The 1:2 AuX/PMe3 (X = Cl,Br,I) complexes have been prepared and studied by infrared, Raman and solid-state cross polarisation magic angle spinning (CP MAS) P-31 NMR spectroscopy. The new complex bis(trimethylphosphine)iodogol d(I) [AuI(PMe3)(2)] was prepared by the reaction of [AuI(PMe3)] with PMe3 i n dimethylformamide solution. A new method for the preparation of the corre sponding bromide complex [AuBr(PMe3)(2)], from [NBu4][AuBr2] and PMe3, is d escribed. The IR, Raman and CP MAS P-31 NMR spectra of the X = Cl, Br compo unds are essentially identical, whereas those for X = I show differences th at are suggestive of relatively minor differences in the crystal structure relative to the X = Cl, Br compounds. The latter compounds exist as the ion ic species [Au(PMe3)(2)]X-+(-), and the X = I complex is also essentially i onic, but with a possible weak Au ... I interaction; this conclusion is sup ported by the Au-197 Mossbauer spectrum of this compound. The solid-state C P MAS P-31 NMR spectra of the chloride and bromide complexes consist of dou blets due to the presence of (1)J(Au-197-P-31) coupling. This study is the first in which such coupling is observed for the P-Au-P coordination enviro nment. The (1)J(Au-197-P-31) coupling constants are estimated from the doub let splittings. (C) 2000 Elsevier Science B.V. All rights reserved.