Small non-polar complexes exhibiting significant piezoelectric properties: Solvothermal synthesis and crystal structures of MO _5V(tren) ·H _2O (M=Mo and W; Tren=tris(2-aminoethyl)amine)

摘要

The two isostructural complexes MO _5V(tren)·H _2O (M=Mo (1) and W (2)) were synthesized under solvothermal conditions at pH≈12 crystallizing in the non-centrosymmetric space group P2 _12 _12 _1. The structures are constructed by a distorted tetrahedral [MO _4] ~(2-) anion bound via one shared oxygen atom to a severely distorted [V ~(IV)N _4O] ~2 complex completing the octahedral coordination around the V centre. The two O atoms in the VN _4O _2 octahedron are in cis position. The two compounds represent rare examples where the [MO _4] ~(2-) anion is acting as a ligand. Both compounds exhibit a piezoelectric effect which is more pronounced for M=Mo. The samples are further characterized with IR and UV/Vis spectroscopy and thermal analysis.