摘要:
In order to further understand the coordination chemistry of diazamesocyclic systems, a series of mononuclear Ni-II complexes with 1,4-diazacycloheptane (DACH) functionalized by additional imidazole or pyridine donor pendants, including [NiL1](ClO4)2 center dot H2O (1), [(NiLCl)-Cl-1](ClO4) (2), [(NiLCl)-Cl-2](ClO4) center dot CH3OH (3), [(NiLCl)-Cl-2][NiL2](ClO4)(3) (4) and [NiL3](ClO4)(2) (5), where L-1 = 1,4-bis(N-1-methylimidazol-2-yl-methyl)-1,4-diazacycloheptane, L-2= 1,4-bis(pyridyl-2-yl-methyl)-1,4-diazacycloheptane, and L-3= 1,4-bis-(imidazol-4-yl-methyl)-1,4-diazacycloheptane, have been prepared and characterized. A detailed study on the solid structures and solution spectra of these complexes indicates that tetradentate ligands L-1, L-2 and L-3 would lead to new Ni-II complexes with different coordination environments in the solid states and solution. The N-methyl substituted imidazole functionalized ligand L-1 forms green compound 2 and yellow product 1; while the pyridine functionalized ligand L-2 affords red product 4 and green complex 3; the ligand L-3 results in only one stable mononuclear Ni-II product 5. The solution behaviors of these interesting compounds were also investigated by UV-Vis technique. (c) 2004 Elsevier B.V. All rights reserved.