Synthesis, structural features and luminescence properties of a 1-D poly(azolato)-based coordination polymer

The novel coordination polymer [Mn(Andolast)(H2O)] was isolated in the form of air- and moisture-stable polycrystalline powders by reacting Mn(CH3COO)2·4H2O and the sodium salt of N-4-(1H-tetrazol-5-yl)phenyl-4-(1H-tetrazol-5-yl) benzamide (Na2Andolast). The crystal structure of [Mn(Andolast)(H2O)], determined by powder X-ray diffraction (PXRD) structure solution methods, is composed by 1-D double-chain motifs. The thermal behavior of [Mn(Andolast)(H2O)] was investigated by coupling thermal analyses to variable-temperature PXRD: water evolution takes place in the range 80-250 °C with no change of the unit cell parameters up to 180 °C; at 200 °C, a low-crystallinity phase is formed, surviving up to 300 °C. The electronic transition spectroscopic properties of both Na2Andolast and the coordination polymer were assessed, with particular care to luminescence: [Mn(Andolast)(H2O)] is luminescent already at room temperature, even if its emission is reduced with respect to that of Na2Andolast, mainly as a consequence of the enhanced rate of non-radiative decays.