Coordination Polymers Ca(II)–Cr(III) and Ba(II)–Cr(III) with Cyclobutane-1,1-dicarboxylic Acid Anions
摘要
The reactions of Cr(NO3)3·9H2O with barium and calcium salts of cyclobutane-1,1-dicarboxylic acid (H2Cbdc) in a ratio of 1 : 3 in an aqueous solution are studied. The reaction products isolated in the crystalline state are shown to be compounds formed by the binuclear tetraanionic units [Cr2(OH)2(Cbdc)4]4–, and the nature of the alkaline-earth metal ion introduced into the synthesis affects the dimensionality of the formed polymeric structure. The 2D polymeric compound {[Ba2Cr2(OH)2(Cbdc)4(H2O)5]·3H2O}n (I) is formed in the reaction with Ba(Cbdc), and the replacement of Ba2+ by Ca2+ results in the formation of the 1D coordination polymer {[Ca2Cr2(OH)(Cbdc)4(H2O)6]·8H2O}n (II). The crystal structures of compounds I and II are determined by single-crystal XRD (CIF files CCDC nos. 2344872 (I) and 2344873 (II), respectively).