Synthesis and structure determination of a new ball-shaped polyoxovanadate with a hexadecanuclear core

Abstract

A new polyoxovanadate species formulated [V 16 O 42 ] 4– was isolated in DMF solvent. Its structure was solved at 100 K by single-crystal X-ray diffraction in the centrosymmetric monoclinic C 2/ c (no. 15) space group with lattice parameters a = 25.554(6) Å, b = 14.227(3) Å, c = 28.485(6) Å, β = 113.21(1)°, V = 9518(4) Å 3 . The refinement of the structure of [(SO 4 ) ⊂ V 16 O 42 ]·(SO 4 ) 2 ((CH 3 ) 2 NH 2 ) 10 ((CH 3 ) 2 NCHO) 4 using 11 389 independent I > 2 σ ( I ) reflections led to reliability factors R 1 ( F o ) and wR 2 ( F o 2 ), respectively, equal to 0.0434 and 0.1269. The structure of the V 16 polyanion, templated by a tetrahedral sulphate group, is built up from one ring of 12 edge-shared V V O 5 square pyramids capped on each side by a dimeric unit. Each entity carries out a six-negative charge, the neutrality of the structure is ensured by the appropriate amount of dimethyl ammonium ions.