Examples of cation exchange in new ionic oxovanadium(IV) complexes with anions of cyclobutane-1,1-dicarboxylic acid

Abstract

The results on the synthesis and study of the crystal structures of compounds based on anionic fragments {VO(Cbdc)₂}^2– formed by oxovanadium(IV) (vanadyl, VO²⁺) and two chelate-bound anions of cyclobutane-1,1-dicarboxylic acid (H₂Cbdc = C₄H₆(COOH)₂) are presented. The use of ammonium cation NH₄⁺ as a counterion in the synthesis leads to the formation of the mononuclear complex (NH₄)₂[VO(Сbdc)₂(H₂O)] · 2H₂O (I). In the case of K⁺ cation, compound [K₄(VO)₂(Сbdc)₄(H₂O)₄]_n (II) with the 3D polymeric crystal structure is formed. The reaction of compound II with Mg(NO3)2 · 6H₂O in an aqueous solution involves the partial substitution of K⁺ by Mg²⁺ cations to form 1D polymeric compound {[KMg_0.5(VO)(Сbdc)₂(H₂O)_6.5] · 3H₂O}_n (III), while a similar reaction of compound I does not afford the product of substitution of NH₄⁺ by Mg²⁺ cations (CIF files CCDC 1551021–1551023 for compounds I–III, respectively).