The Syntheses, Crystal Structures And Characterization Of Polyoxometalate Compounds

In this thesis, four novel compounds were synthesized which are organotin -substituted polyoxomolybdate H48Mo30O88{Mo(NO)O6}4{Sn(n-Bu)O4}4-9H2O(1), {CrLa(H2O) (C2H5OH)}2{CrLa(C2H5OH)2}PMo12O40(La=2,2'-N,N'-bis(salicylidene)ethylenediamine, 2), {CrLa(H2O)2}4Mo8O26(3) and C49H63Mo12N6O48P(4). Their crystal structures were determined by X-ray single crystal diffraction method.Compound 1 is a 38-nuclear organotin-substituted polyoxomolybdate which consists of two identical {Mo17Sn2} subunits related to each other by a center of inversion. Each of the subunit contains a variety of polyhedra: one MoVIO6, one (O=)MoVIO4(H2O), three (O=)2MoVI O3(H2O), four (O=)MoVIO5, one (O=)2MoVIO4(Mo9), one (O=)2MoVIO3(H2O), two (O=)SnIV (n-Bu)04 octahedra, and two pentagonal Mo II (NO)+O64 bipyramids and four MoVI 2O8(u-O)(u-H2O) units consisting of edge-shared octahedra. Organotin-substituted isopolymolybdate has never been reported before, and 1 is the first example of such kind of compound.Compounds 2 and 3 are two Cr(III) complexes with bis(salicydene) Schiff base ligand. PMo12O403- is the counterions of compound 2, and Mo8O264- is the counterions of compound 3. In both 2 and 3, Cr(III) cation is six-coordinated by two N atoms and two O atoms from one La2- anion, and two solvent molecules.Cr(III) complex with bis(salicydene) Schiff base ligand is destroyed during the preparation of the target compound, and compound 4 is obtained. This is probably caused by the catalytic effect of heteropolyacid. Compound 4 is the phosphomolybdate of 2-(2-hydroxylphenyl)benzimidazole. Each independent unit consists of three protonated 2-(2-hydroxylphenyl)benzimidazole molecules and one PMo12O403- anion. Each 2-(2-hydroxylphenyl)benzimidazole molecule carries one positive charge, and PMo12O403-ion is the counterions.