Adduct Formation between Alkali Metal Ions and Anionic LVVO2- (L2- = Tridentate ONS Ligands) Species: Syntheses, Structural Investigation, and Ph

详细信息    查看全文

• 作者：Satyabrata Samanta ; Suman Mukhopadhyay ; Debdas Mandal ; Ray J. Butcher ; and Muktimoy Chaudhury
• 刊名：Inorganic Chemistry
• 出版年：2003
• 出版时间：October 6, 2003
• 年：2003
• 卷：42
• 期：20
• 页码：6284 - 6293
• 全文大小：272K
• 年卷期：v.42,no.20(October 6, 2003)
• ISSN：1520-510X

文摘

Syntheses of alkali metal adducts [LVO₂M(H₂O)_n] (1-7) (M = Na⁺, K⁺, Rb⁺, and Cs⁺; L = L^1-L³) of anioniccis-dioxovanadium(V) species (LVO₂^-) of tridentate dithiocarbazate-based Schiff base ligands H₂L (S-methyl-3-((5-(R-2-hydroxyphenyl))methyl)dithiocarbazate, R = H, L = L¹; R = NO₂, L = L²; R = Br, L = L³) have beenreported. The LVO₂^- moieties here behave like an analogue of carboxylate group and have displayed interestingvariations in their binding pattern with the change in size of the alkali metal ions as revealed in the solid state fromthe X-ray crystallographic analysis of 1, 3, 6, and 7. The compounds have extended chain structures, forming ionchannels, and are stabilized by strong Coulombic and hydrogen-bonded interactions. The number of coordinatedwater molecules in [LVO₂M(H₂O)_n] decreases as the charge density on the alkali metal ion decreases (n = 3.5 forNa⁺ and 1 for K⁺ and Rb⁺, while, for Cs⁺, no coordinated water molecule is present). In solution, compounds 1-7are stable in water and methanol, while in aprotic solvents of higher donor strengths, viz. CH₃CN, DMF and DMSO,they undergo photoinduced reduction when exposed to visible light, yielding green solutions from their initial yellowcolor. The putative product is a mixed-oxidation (-oxo)divanadium(IV/V) species as revealed from EPR, electronicspectroscopy, dynamic ¹H NMR, and redox studies.