This paper reports the syntheses of four benzimidazolyl-containing ligands: ortho-bis[N, N'-bis(2'-benzimidazolyl-methyl) amino]-trans-cyclohexane (OCTB) and its three alkylsubstituted derivatives. Dicopper(Ⅰ) complexes 1-4 were respectively prepared through the reactions of the ligands with [Cu(CH~3CN)~4]ClO~4. Elemental analysis, IR spectra and ^1H NMR show that the compositions of the ligands and the complexes are the same as desired. UV-vis spectra indicate the complexes 1-4 can combine with dioxygen. The colorless solutions of the complexes in DMF show an uptake of oxygen and give green solutions with a wide absorption peak about at 700nm. Addition of ascorbic acid (AA) results in decolorization of the solutions and the cycle can be repeated three or four times. Equilibrium constants, △H°and △S°of oxygenation reactions of the complexes in DMF are obtained by manometric oxygen-uptake measurements. We consider that the steric hindrance on N atom of benzimidazole is unfavourable to oxygenation. The electron-donating substituents on N atom would increase the electron density of coordination atom and further the central ion Cu(Ⅰ) and make the oxygenation more easier. The oxygenation rates in different solvents are in the order of DMF＞DMSO＞Py.

Key words: HEMOCYANIN, DINUCLEAR COMPLEX, CARRIER OF OXYGEN