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

摘要

A new polyoxovanadate species formulated[V16O42]~(4-)was isolated in DMF solvent.Its structure was solved at 100 K by single-crystal X-ray diffraction in the centrosymmetric monoclinic C2/c(no.15)space group with lattice parameters a=25.554(6)A,b=14.227(3)A,c=28.485(6)A,beta=113.21(1)°,V=9518(4)A3.The refinement of the structure of[(SO4)is contained in V16O42]·(SO4)2((CH3)2NH2)10((CH3)2NCHO)4 using 11 389 independent I>2 sigma(I)reflections led to reliability factors R1(F_o)and wR2(F_o~2),respectively,equal to 0.0434 and 0.1269.The structure of the V16 polyanion,templated by a tetrahedral sulphate group,is built up from one ring of 12 edge-shared V~vO_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.