Syntheses, Structures, and Some Properties of Three Vanadium Selenites

Three novel vanadium selenites with the formulae(VO2)(1,10-phenanthroline)(SeO3H)]2 1,(VO2)(2,2'-bipyridine)]2(SeO3)2 and(VO)(H2O)(SeO3)2]2(H4EDD)3(EDD=N1,N1'-(ethane-1,2-diyl)diethane-1,2-diamine)were hydrothermally synthesized,and characterized with elemental analysis,FT-IR spectrum,Raman spectrum,TG-DTA analysis,EPR spectra,and single-crystal X-ray diffraction analysis.Compound 1 belongs to the triclinic system,space group Pi with a=7.7527(5),b=9.5345(10),c=9.8192(8)(A),a=92.712(3),β=105.540(3),γ=108.154(4)°,V=657.66(1)(A)3,Mr=782.22,Z=1,F(000)=384,μ(MoKα)=3.544 mm-1,R=0.0432 and wR=0.1142;Compound 2 is of orthorhombic system,space group P212121 with α=7.6574(15),b=14.916(3),c=19.085(4)A,V=2179.8(8)(A)3,Mr=605.21,Z=4,F(000)=1200,μ(MoKα)=2.579 mm-1,R=0.0338 and wR=0.0658;Compound 3 belongs to the triclinic system,space group P(i) with a=9.247(2),b=9.659(2),c=7.2651(19)(A),α=98.171(7),β=103.709(5),γ=114.712(13)°,V=550.9(2)(A)3,Mr=828.03,Z=1,F(0010)=400,μ(MoKa)=7.537 mm-1,R=0.0641 and wR=0.2118.Compound 1 is constructed from alternating comer-sharedVO4N2] octahcdra and SeO3H units,forming a dimenc vanadium unit.These assemblies are further linked into an infinite chain via hydrogen bonds along the a axis.In the structure of 2,two distinct V centers form centrosymmetricV2O6N4]clusters through edge-sharing,and the SeO3 unit serves as a capping unit to fix the oxovanadate cluster.In the structure of 3,eachVO6]octahedron shares four oxygen atoms with adjacent Se atoms,while every SeO3 unit shares two oxygen atoms with neighboring Ⅴ atoms.This connectivity of alternating VO6 and SeO3 units results in a joint-like chain.Based on the TGA analysis.these three compounds are thermally stable under 200℃.