Author/Authors :
Aghabozorg، Hossein نويسنده , , Firoozi، Najmeh نويسنده Faculty of Chemistry, , Tehran, I.R. IRAN , , Roshan، Leila نويسنده Faculty of Chemistry, Tarbiat Moallem University, Tehran, I.R. IRAN , , Mirzaei، Masoud نويسنده Department of Chemistry, Ferdowsi University of Mashhad, P.O. Box 91779-1436 Mashhad, I.R. IRAN , , Shokrollahi، Ardeshir نويسنده Department of Chemistry, Yasuj University, Yasuj, I.R. IRAN , , Aghaei، Roghayyeh نويسنده Department of Chemistry, Yasuj University, Yasuj, I.R. IRAN , , Aghlmandi، Ziba نويسنده Faculty of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, I.R. IRAN ,
Abstract :
In the crystal structure of the title polymeric compound, [C42H38N6O33Sr5.2(H2O)]n, five independent metal atoms (Sr1-Sr5) have different coordination environments. The Sr1 and Sr5 atoms are nine coordinated and feature distorted tricapped trigonal-prismatic and capped
square-antiprismatic geometries, respectively. The rest SrII atoms have eight coordination numbers. These units are connected via the carboxylate O atoms of mono- and di anionic forms of pyridine-2,6-dicarboxylic acid, (pydcH2), and bridging water molecules that resulted in the formation of polymeric layers in 3-D. In the crystal structure, non-covalent interactions consisting of hydrogen bonds (O—H•••O and C—H•••O), ?–? [interplanar distances of 3.413(2); 3.601(2) ?] and C?O•••? [O•••? distances of 3.249(3); 3.275(3) ?] stacking interactions play an important roles in stabilizing the structure. The protonation constants of propane-1, 2-diamine (1, 2-pn) and pyridine-2,6-dicarboxylate ion (pydc)2–, the equilibrium constants for the pydc-1,2-pn proton transfer system and the stoichiometry and stability of this system with Sr2+ ion in aqueous solution were investigated by potentiometric pH titrations. The stoichiometry of one of the most abundant complexed species in solution was found to be the same as that of the crystalline SrII complex.
