Coordination chemistry of polyoxo-carbocyclic compounds containing one or more neighboring oxo-groups

Abstract This is a review of publications concerning the results of X-ray analysis of single crystals and spectrochemical characteristics of metal complexes containing polyoxo-carbocyclic compounds with one or more neighboring oxo-groups. The features of lattice characteristics and coordination modes, depending on the nature of the organic dianion, are shown here. The squarate anions, ${{\rm{C}}_{\rm{4}}}{\rm{O}}_{\rm{4}}^{{\rm{2 - }}}$ are predominantly involved in monodentate bridging coordination, and the derivatives containing five or six C-atoms in the cycle (croconate and rhodizonate anions) usually form bidentate chelating bridged modes. The stabilization of the crystal lattices of the metal complexes is due to the formation of hydrogen bonds and π-π stackings, which produce self-assembled three-dimensional (3D) structures with cavities and intercalation of some small molecules. The strong interlayer interactions lead to appearance of specific conductometric and magnetic properties, which together with their high thermal stabilities, make the oxocarbon complexes new and perspective materials for electronics and related areas.