Synthesis of mono- and bis-tetrazolato complexes of Ni(II), Pt(II) and Cu(II) via 1,3-dipolar cycloadditions of 2-cyanopyridines with metal ligated azides in N,N,O-aminoiminophenolato complexes

Reactions of the aminoiminophenols 2-((2-(dimethylamino)ethylimino)methyl)phenol (HL1) or 2-{(3-(dimethylamino)propylimino)methyl}phenol (HL2) with nickel(II) chloride, K-2[PtCl4] or copper(II) acetate in alcoholic solution, in the absence or in the presence of sodium azide, afford the corresponding new mononuclear complexes [M(L-1)(X)(H2O)(n)] [M = Ni, X = Cl-, n = 2 (1); M = Ni, X = N-3(-), n = 0 (2); M = Pt, X = Cl- (3) or N-3(-) (4), n = 0] or the known dinuclear compound [Cu(L-2)(N-3)](2) (5). Complexes 2, 4 and 5 react with 2- cyanopyridine leading to the [2 + 3] cycloaddition products with 5-(2-pyridyl)tetrazolato [PTZ = N4C(2-NC5H4)] ligands [Ni(L-1)(PTZ)](2) (6), [Pt(L-1)(PTZ)] (7) and [Cu(PTZ)(2)(H2O)(2)] 8. The obtained complexes were characterized by IR, H-1 and C-13 (for 3, 4 and 7) NMR spectroscopies, elemental analyses and single crystal X-ray diffraction analyses (for 1, 2, 3, 4, 6 and 8). Complexes 1 and 8 form finite 1D chains and 3D frameworks, respectively, on account of extensive hydrogen bonds involving their coordinated water molecules and the chloride ligand (in the case of 1) or tetrazolato nitrogen atoms (in the case of 8).