Dioxouranium complexes as ligand. Synthesis and characterization of sandwich-type polyoxometalates [X2W18(UO2)2{(H2O)3M}2O68] (X = As and P) (M = Co, Cu, Mn, Ni and Zn) |
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Authors: | Roushan Khoshnavazi Leila Kaviani |
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Institution: | a Department of Chemistry, University of Kurdistan, P.O. Box 66135-416, Sanandaj, Iran b Faculty of Chemistry, Damghan University of Basis Science, Damghan, Iran |
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Abstract: | The title complexes are synthesized by the reaction of an unusual ligand of K2P2W18(UO2)2O68]12− (1) and KAs2W18(UO2)2O68]13− (2) with divalent metal ions of CoII, CuII, MnII, NiII and ZnII in 1:2 mole ratio and are characterized by elemental analysis, IR, 31P NMR, UV-Vis spectroscopy, TGA, and single crystal structure analysis. Crystals of P2W18(UO2)2{(H2O)3Co}2O68]10− (1a) and As2W18(UO2)2{(H2O)3Cu}2O68]10− (2b) are orthorhombic space group Cmca. Both 1a and 2b have structures in which two M(H2O)3] (M = CoII, CuII) and two UO2 groups are sandwiched between two symmetry equivalent (XW9) (X = P, As) units in a virtual Ci symmetry. In solution, 1a and P2W18(UO2)2{(H2O)3Zn}2O68]10− (1d) give two-line P NMR spectra that are consistent with a Cs symmetry structures so, are not consistent with the solid-state structures. The sodium salts of them give one-line P NMR spectra and are consistent with the Ci symmetry of solid-state structures. The uranium atoms have pentagonal-bipyramidal coordination, achieved by three equatorial bonds to the one XW9 and two bonds to the other. The M atoms have octahedral or square pyramidal coordination, but only one bond to the one XW9 and one bond to the other. |
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Keywords: | Polyoxometalates Sandwich-type complexes Uranyl complexes Divalent transition metal ion complexes Single crystal analysis |
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