Hydrothermal syntheses and crystal structures of new cage-like mixed-valent polyoxovanadates

Abstract

Three new cage-like mixed-valent polyoxovanadates [Ni(1,10′-phen) 3] 2[V 10O 26] 1, [Zn(2,2′-bipy) 3] 3[V 15O 36Cl]·3H 2O ( 2) and [Co(2,2′-bipy) 3] 3[V 15O 36Cl]·3H 2O ( 3) have been hydrothermally synthesized for the first time and characterized by elemental analyses, IR, EPR spectra, TG analyses and single crystal X-ray diffraction. The polyoxoanion of 1 exhibits an interesting empty ellipsoidal [V IV 2V V 8O 26] 4− ‘host’ shell, while the oxo vanadium clusters of 2 and 3 possess a spherical [V IV 8V V 7O 36Cl] 6− cage with a Cl − ion encapsulated. The structure-directing role of organic templates (1,10′-phen and 2,2′-bipy) on the formation of the polyoxoanion structures is discussed.