A novel series of nickel(II)-dppe-arylazoimidazole complexes. Synthesis and spectroscopic characterization

Reaction of [Ni(dppe)Cl-2/Br-2] with AgOTf in CH2Cl2 medium following ligand addition leads to [Ni(dppe)(OSO2CF3)(2)] and then [Ni(dppe)(RaaiR)](OSO2CF3)(2) [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]. P-31{H-1}-NMR confirm that stable bis-chelated square planar Ni(II) azoimine-dppe complex formation with one sharp peaks. The H-1 NMR spectral measurements suggest azoimine link is present with lot of phenyl protons in the aromatic region. Considering all the moities there are a lot of different carbon atoms in the molecule which gives many different peaks in the C-13(H-1)-NMR spectrum. In the H-1-H-1 COSY spectrum in the present complexes and contour peaks in the H-1-C-13-HMQC spectrum in the present complexes, assign the solution structure and stereoretentive conformation in each complexes.