One-dimensional chain structures of hexanuclear uranium(iv) clusters bridged by formate ligands

Three one-dimensional chain structures of uranium(iv) hexanuclear clusters have been synthesized under hydrothermal/solvothermal conditions. Crystallographic studies disclose that the structures of [U O (OH) (HCOO) (H O)]·3H O (1a), [U O (OH) (HCOO) (HCOOH)(H O)]·3H O (1b) and (H C N) [U O (OH) (HCOO) (H C N)] (2) contain a U(iv) hexanulear core [U ( -OH) ( -O) ] which is decorated by terminal HCOO ligands and water (1a, 1b), HCOOH (1b) or pyridine molecules (2). These hexanuclear U(iv) clusters are further linked into zig-zag 1-D chain structures bridging HCOO ligands. UV-vis-NIR spectra, together with bond valence calculations, indicate that all U atoms in three compounds exist as U(iv). Magnetic susceptibility data reveal that compound 2 exhibits paramagnetic characteristics.