Antibacterial activity assays of a new cadmium complex with o-phenanthroline and cyanoguanidine. Crystal structure, fluorescence properties and chemical speciation studies

L. L. LÓPEZ TÉVEZ; J. J. MARTÍNEZ MEDINA; M. S. ISLAS; O. E. PIRO; E. E. CASTELLANO; L. BRUZZONE; E. G. FERRER; P. A. M. WILLIAMS

JOURNAL OF COORDINATION CHEMISTRY

TAYLOR & FRANCIS LTD

Año: 2011 vol. 64 p. 3560 - 3574

0095-8972

A new coordination complex, aqua bis(o-phenanthroline) cadmium(II)  sulphate cyanoguanidine pentahydrate, [Cd(o-phen)2(SO4)(H2O)](cnge).5H2O, was synthesized and characterized. The crystal structure was solved by X-ray diffraction methods. It crystallizes in the monoclinic space group P21/n with a=13.7650(2), b=10.2796(2), c=21.4418(3) Å, beta=90.106(2)°, and Z=4 molecules per cell unit. The cadmium(II) ion is in a distorted octahedral environment coordinated to two nearly planar and mutually perpendicular o-phenanthroline, one oxygen of the sulfate ion and a water molecule. An un-bonded to metal and planar cyanoguanidine moiety and five crystallization water molecules complete the asymmetric unit contents. Vibrational (FT-IR and FT-Raman) spectroscopies and thermogravimetric determinations support this structure. Besides, the intensity enhancement of the fluorescence spectrum may be a demonstration of the interaction of the metal with the phenanthroline ligand. In solution the coordination behavior is rather different, and the speciation studies point to coordination of both cnge and phenanthroline to the metal center. The improvement of the antibacterial activity of cadmium upon complexation has been determined.