IR spectroscopic investigation of cis-(CH3)2Au(O,O′-acac) and cis-(CD3)2Au(O,O′-acac)

The IR spectrum of cis-(CH3)2Au(O,O′-acac) has been reassigned by comparing frequencies for cis-(CH3)2Au(O,O′-acac) and cis-(CD3)2Au(O,O′-acac), and by analysis of the DFT-calculated normal modes and their frequencies for the isolated molecules. The vibrational intensity in the C–H stretching region arises almost entirely from the cis-(CH3)2Au fragment, while the methyl deformation intensity is largely of acetylacetonato ligand origin. A low frequency mode in the C–H stretching region is the first overtone of the δa(CH3) mode of cis-(CH3)2Au. The Au–C stretching modes are affected by deuteration of the cis-(CH3)2Au fragment, while the Au–O stretching modes are not.