Synthesis and Multinuclear NMR Investigation on Binuclear Gold(I)-Diphenylphosphinoammine (dppa)-Arylazoimidazole Complexes

Reaction of [Au2(dppa)Cl2] with AgOTf in dichloromethane medium followed ligand addition leads to [Au2(dppa)(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, dppa is diphenylphosphinoammine ring]. The maximum molecular peak of the corresponding molecule is observed in the ESI mass spectrum. Ir spectra of the complexes show -C=Nand -N=Nstretching near at 1590 and 1370 cm. The H NMR 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 av. 6.2 Hz. Considering all the moitie there are a lot of different carbon atoms in the molecule which gives a lot of different peaks in the C NMR spectrum. In the H-H COSY spectrum of the present complexes and contour peaks in the H-C HMQC spectrum in the present complexes, assign the solution structure and stereoretentive transformation in each step.