Abstract
In this paper methenamine (HMTA) ligand acts as monodentate with each central atom in all isolated complexes although the ligand molecule possesses four potential donor atoms through three fused rings in the chair configuration with four bridges - head nitrogen atoms. The nitrogen atoms of this donor may permeate the coordination towards multinucleous of metal atoms. This behavior may be due to the shape of the ligand distribute the donor atoms by the shape leads to this coordination. Ag(I), Cd(II), Cu(II), Hg(II), Sn(II), Sn(IV), Sb(III), Bi(III), Ce(III), Sm(III) and La(III) are the metal ions concerned this study. In the infrared spectra the shift in upsilon(C-N) bands proposed the type of coordination mode. The (HNMR)-H-1 spectra of Sn(II) and Bi(III) complexes are further supported for the proposed chelation. The XRD study for some selective complexes reflects their amorphous nature. The thermal behavior of these chelates shows that the hydrated complexes losses water molecules of hydration and coordination at relatively higher temperature. This is due to the presence of hydrated molecules introduced by H - bonding inside the coordination sphere with the active ligand centers followed immediately by decomposition of anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters as; E*, Delta H*, Delta S* and Delta G* are calculated from the TG curves using Coats - Redfern method for suitable TG curves in between the all, which display peaks in between sharpness and broadness. The ligand in comparison to some of complexes was screened for their antibacterial and antifungal activities. The application was concerned in this study with focusing on some special complexes chosen referring to their history of their distinguish activity. The activity data show the investigated metal complexes to be more potent than the parent organic against most species. [Soha F. Mohammed, Moamen S. Refat, and Nashwa M. El-Metwaly. Synthesis a New Series of Methenamine Complexes with Some Different Metal Ions: Spectral, Thermal and Biological Investigations. Life Sci J 2012;9(2):1243-1253] (ISSN: 1097-8135). http://www.lifesciencesite.com. 185