1D coordination polymers with polychalcogenides as linkers between metal atoms

The reactions of zinc metal with elemental selenium and selenium/sulfur mixtures in liquid ammonia or methylamine under solvothermal conditions in closed glass ampoules at 50 degrees C lead within some days specifically to [Zn(NH3)(2)Se-4](n) (1), [Zn(MeNH2)(2)Se-4](n) (2) [Zn(MeNH2)(2)Se2.23S1.77](n) From MoCl2, Rb2Se and excess Se in n-butylamine [Mn((BuNH2)-Bu-n)(4)Se-6] (4) is obtained after prolonged reaction time at ambient temperature. The compounds are sensitive towards air and loss of NH3 or the amine ligands. The crystal structures were determined by single crystal diffraction at low temperatures. As a common structural feature, all compounds represent 1D coordination polymers with polychalcogenide chains as linkers between the metal atoms and consist of infinite [M-Ch(m)-](n), chains (M=Zn, Mn; Chm=Se-4, (S/Se)(4), Se-6). The Zn central atoms in 1-3 have tetrahedral coordination with two amine ligands, the Mn atoms in 4 have octahedral coordination with four amine ligands and cis position of the two Se atoms. Raman spectra of 1-3 show the stretching mode vibrations of the Ch(4) groups. The observation of S-S. S-Se, and Se-Se vibration bands in the spectrum of 3 indicates the presence of mixed S/Se polyanions. An optical band gap of 1.86(5) eV was determined for 2 by diffuse reflectance spectroscopy. (C) 2013 Elsevier Inc. All rights reserved.