Uranyl–Organic Coordination Polymers with trans-1,2-, trans-1,4-, and cis-1,4-Cyclohexanedicarboxylates: Effects of Bulky PPh4+ and PPh3Me+ Counterions

Abstract

Three uranyl ion complexes with trans-1,2-cyclohexanedicarboxylic acid (t-1,2-chdcH2) and six with trans- or cis-1,4-cyclohexanedicarboxylic acid (t- or c-1,4-chdcH2) have been obtained under solvo-hydrothermal conditions in the presence of PPh4+ or PPh3Me+ counterions. The complex [PPh4][UO2(R-t-1,2-chdc)(HCOO)] (1) crystallized on use of the pure (1R,2R) enantiomer of the dicarboxylate ligand, while the isomorphous complex [PPh4][UO2(S-t-1,2-chdc)(HCOO)] (2), containing the (1S,2S) enantiomer, resulted from use of the racemic form through spontaneous resolution. Both contain the rare diaxial (aa) form of the ligand and are one-dimensional (1D) polymers. The complex [PPh3Me][H2NMe2]3[(UO2)4(R-t-1,2-chdc)6]·H2O (3), with the pure enantiomeric, diequatorial (ee) form of the ligand, is a two-dimensional (2D) species with hnb topology, which derives from the structure of tetranuclear clusters previously reported. Complexes [PPh4][UO2(t-1,4-chdc)(NO3)]·2CH3CN (4) and [PPh4][UO2(c-1,4-chdc)(NO3)] (5) are 1D po...