title: Two-dimensional bicapped supramolecular hybrid semiconductor material constructed from the insulators α-Keggin polyoxomolybdate and 4,4'-bipyridine.
abstract: A new organic-inorganic hybrid material [SiMo14O44](H4,4'-bpy)2·xH2O (4,4'-bpy = 4,4'-bipyridine) was synthesized using a hydrothermal method. The compound was characterized using single crystal X-ray diffraction (XRD), infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). XRD studies on selected single crystals suggested that the compound consists of supramolecular 2D layer structures composed of capped α-Keggin polyoxomolybdate anions and 4,4'-bpy organic ligands. Absorption measurements show a band gap of 2.99 eV in the hybrid which suggests a semiconducting nature compared to the insulating free α-Keggin and 4,4'-bpy. The magnetic susceptibility of the hybrid material was investigated in the temperature range 1.8-300 K obeying the Curie-Weiss law above 70 K. Experimentally measured magnetic moment of 2.71 μB/formula indicates possible mixed valent molybdenum in the compound. The XPS measurements confirm the presence of both Mo(V) and Mo(VI) in the ratio 15:85 resulting in the structural formula of the hybrid as [SiMo(V)2Mo(VI)12O44](H4,4'-bpy)2·xH2O.
authors.affiliation: New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bangalore, 560064 India.
authors.forename: Abishek K
authors.initials: AK
authors.lastname: Iyer
authors.forename: Sebastian C
authors.initials: SC
authors.lastname: Peter