Tris(2-benzimidazolylmethyl0amine cobalt (Ⅱ) (complex a) and tris(2- benzimidazolylmethyl) amine zinc (Ⅱ)(complex b) were synthesized. Their crystal structures were determined by X-ray method. Elemental analysis and IR spectra of the two title compounds were performed. The results show that complexes a and b are a pair of isomorphors. During the formation of the complexes, the two N-atoms of NTB were unprotonated. The crystals are cubic, I-43d space group, with a=b=c=2.2353(3)nm, V=11.169nm^3, Z=16. The final refinement converged to R=0.0686(a) and 0.0688(b). In the two complexes, the metal atom is coordinated with one nitrogen atom of alkylamine and three sp^2 nitrogen atoms from NTB and one oxygen atom from H~2O to form a distorted trigonal-bipyramid configuration. The quantum calculation was performed by the method of density function. The results show that the NTB molecule tends to be unprotonted, which is consistent with that of the crystal structure.

Key words: ISOMORPHISM, BENZIMIDAZOLE P, COBALT COMPLEX, ZINC COMPLEX, ELEMENTAL ANALYSIS, INFRARED SPECTROPHOTOMETRY, X-RAY DIFFRACTION ANALYSIS, QUANTUM CHEMISTRY