Synthesis, IR Study and Crystal Structure of a Novel Mononuclear Tungsten(VI) Oxo Complex with 1-Hydroxyethylidenediphosphonic Acid, Exhibiting a WO3 Core

The synthesis and IR spectroscopic and X-ray diffraction studies of [C(NH₂)₃]₅[WO₃(L^*)]·4.5H₂O, the first W^VI monomeric compound to contain a WO₃ group, have been carried out and an unusual structure (with ratio M:L^* = 1:1) has been observed for both independent complex anions: the tungsten atoms have fac-octahedral coordination with three terminal oxo-atoms (O_t), two O(P) atoms and one O(C) atom of the tridentate ligand L^* in the trans position to O_t.