Computational study and spectroscopic investigations of the [Zn(phen)2(cnge)(H2O)](NO3)2 ? H2O complex

OKULIK NORA; J.J. MARTÍNEZ MEDINA; M.S. ISLAS; FRANCA, C.; P.A.M. WILLIAMS

Santiago de Chile

Congreso; WATOC 2014; 2014

Pontificia Universidad Católica de Chile

Zinc is an essential metal and plays an important roll in catalytic, structural, and regulatory functions. Complexation is associated with zinc in biological systems. To simulate nitrogen environments around Zn(II), we propose the use of cyanoguanidine (cnge) and o-phenanthroline (o-phen). The [Zn(phen)2(cnge)(H2O)](NO3)2?H2O complex was synthesized at high pH and the crystal structure was determined by X-ray diffraction methods. The complex was characterized both in the solid state and in the solution by FT-IR, Raman, and fluorescence spectroscopies, respectively. The X-ray diffraction data was employed to optimize the geometry of the complex using tools from the density functional theory as implemented in the Gaussian 09 package. The cation complex geometry optimization was carried out considering both cyanoguanidine tautomers (cyanoimine and cyanoamine).Theoretical calculations were carried out simulating water environment using the conducting polarizable continuous model (CPCM) as implemented in the software package. The optimizations were accomplished using the Becke?s density functional for exchange with the gradient-corrected correlation functional due to Lee et al. a combination that gives rise to the known B3LYP method. Basis sets of triple-zeta quality with polarized (TZVP) functions for atoms of Zn, C and H, and a TZVP basis set with diffuse functions (TZVPD) for oxygen and nitrogen atoms. Vibrational calculations at the same level of theory were performed to determine the consistency of the minimum in the potential energy surface and to assign the theoretical infrared spectra. The theoretical infrared spectra of two optimized complexes were summarized and compared with the experimental spectra. The vibrational assignments were performed and findings of theoretical calculations agree with those obtained from experimental spectra.