The First Noncluster Vanadium(IV) Coordination Polymers: Solvothermal Syntheses, Crystal Structure, and Ion Exchange

Abstract

Two isostructural vanadium(IV) coordination polymers [VO(dod)2]X2 [X=Cl, Br; dod=1,4-diazoniabicyclo[2,2,2] octane-1,4-diacetate (C10H16N2O4)] have been synthesized solvothermally and determined by single-crystal X-ray analysis. Both of them crystallize in the tetragonal space group P4/ncc (no. 130), with cell parameters a=15.702(5), c=9.745(5) Å, V=2403(2) Å3, Z=4 for 1 and a=15.916(5), c=9.820(4) Å, V=2488(2) Å3, Z=4 for 2. In both complexes, each vanadium atom adopts a VIVO5 square-pyramidal environment, being coordinated by four oxygen atoms [V–O=1.978(2) Å for 1 and 1.969(3) Å for 2] from four dod ligands and a terminal oxygen atom [V=O=1.580(5) Å for 1 and 1.572(7) Å for 2]. The bis-monodentate dod ligands bridge vanadium atoms to furnish two-dimensional double wave-like layers of (4,4) topological type. Along the c-axis direction, there are square channels constructed from side-sharing saddle-shaped rings. The microporous material 1 shows chloride-to-sulfate exchange properties in aqueous media.