Marcos Loroño

Tetradentate metal complexes derived from cephalexin and 2,6-diacetylpyridine bis(hydrazone): Synthesis, characterization and antibacterial activity.

Metal(II) coordination compounds of a hydrazone ligand (HL) derived from the condensation of cephalexin antibiotic with 2,6-diacetylpyridine bis(hydrazone) were synthesized. The hydrazone ligand and mononuclear [ML(H2O)2][PF6] (M(II)=Mn, Co, Ni, Zn) complexes were characterized by several techniques, including elemental and thermal analysis, molar conductance and magnetic susceptibility measurements, electronic, FT-IR, EPR and (1)H NMR spectral studies. The cephalexin 2,6-diacetylpyridine bis(hydrazone) ligand HL behaves as a monoanionic tetradentate NNNO chelating agent. The biological applications of complexes have been studied on two bacteria strains (Escherichia coli and Staphylococcus aureus) by agar diffusion disc method.

Harmonic force constants of boron trihalides and some mixed halides of boron

Abstract A reliable set of harmonic force constants was calculated for BF 3 , BCl 3 , BBr 3 , BI 3 , BF 2 Cl, BF 2 Br, BCl 2 F, BCl 2 Br, BBr 2 F, and BBr 2 Cl using the observed vibrational frequencies of these compounds (containing 10 B or 11 B isotopes) and the iterative consistency method. The final force field reproduces quite satisfactorily the experimental frequencies. Some of the principal stretching force constants were found to vary systematically with the electronegativity of the halogen.