Gold(I)-diphenylphosphinomethane–arylazoimidazole: synthesis and multinuclear NMR investigation

Reaction of [Au2(dppm)Cl2] with AgOTf in CH2Cl2 medium followed ligand addition and leads to [Au2(dppm)(RaaiR′)](OTf) [RaaiR′ = p-R–C6H4–N = N–C3H2–NN–1–R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3(2), CH2Ph (3), OSO2CF3 is the triflate anion, and dppm is the diphenylphosphinomethane-ring]. The 1H-n.m.r. spectral measurements suggest methylene, –CH2–, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph it shows AB type quartets with coupling constant of avg. 6 Hz. Considering all the moities there are a lot of different carbon atoms in the molecule which gives a lot of different peaks in the 13C-n.m.r spectrum. In the 1H–1H-COSY spectrum of the present complexes and contour peaks in the 1H–13C-HMQC spectrum in the present complexes, assign the solution structure and stereoretentive transformation in each step.