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

Abstract

Reaction of [Ni(dppe)Cl2/Br2] 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]. 31P{1H}-NMR confirm that stable bis-chelated square planar Ni(II) azoimine–dppe complex formation with one sharp peaks. The 1H 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 13C(1H)-NMR spectrum. In the 1H-1H COSY spectrum in the present complexes and contour peaks in the 1H-13C-HMQC spectrum in the present complexes, assign the solution structure and stereoretentive conformation in each complexes.