2,5-Thiophenedicarboxylate: An Interpenetration-Inducing Ligand in Uranyl Chemistry

Inorg Chem. 2021 Jun 21;60(12):9074-9083. doi: 10.1021/acs.inorgchem.1c01069. Epub 2021 Jun 10.

Abstract

Seven uranyl ion complexes have been crystallized under solvo-hydrothermal conditions from 2,5-thiophenedicarboxylic acid (tdcH2) and diverse additional, structure-directing species. [UO2(tdc)(DMF)] (1) is a two-stranded monoperiodic coordination polymer, while [PPh3Me][UO2(tdc)(HCOO)] (2) is a simple chain with terminal formate coligands. Although it is also monoperiodic, [C(NH2)3][H2NMe2]2[(UO2)3(tdc)4(HCOO)] (3) displays an alternation of tetra- and hexanuclear rings. Two-stranded subunits are bridged by oxo-coordinated NiII cations to form a diperiodic network in [UO2(tdc)2Ni(cyclam)] (4), but a homometallic sql diperiodic assembly is built in [Cu(R,S-Me6cyclam)(H2O)][UO2(tdc)2]·H2O (5), to which the counterion is hydrogen bonded only. Diperiodic networks with the hcb topology are formed in both [Zn(phen)3][(UO2)2(tdc)3]·2H2O·3CH3CN (6) and [PPh4]2[(UO2)2(tdc)3]·2H2O (7). The slightly undulating layers in 6 are crossed by oblique columns of weakly interacting counterions in polythreading-like fashion. In contrast, the larger curvature in 7 allows for three-fold, parallel 2D interpenetration to occur. These results are compared with previously reported cases of interpenetration and polycatenation in the uranyl-tdc2- system.