Chain of water hexamers and tetramers hosted in a redox product of a Co(III) metal complex: Syntheses, characterization and single crystal X-ray structure determination of Co(II/III) complexes with sulfur oxo-anions

摘要

In the present study, four new Co(II/III) metal complexes, [Co(phen)_3]S_4O_6·2H_2O (1), [Co(phen)_3] S_4O_6·7H_2O (2), [Co(phen)_3]_2(S_4O_6)_3·6.5H_2O (3) and [Co(phen)_3]S_2O_3·9H_2O (4), have been synthesized and characterized by elemental analysis, TGA and various spectroscopic techniques. In the case of 1 and 2, an unexpected redox reaction took place and the complexes formed are different in terms of their water of crystallization. The structures of 1-3 have been determined by single crystal X-ray crystallography. Complex salts 1-3 crystallize in the orthorhombic (Pbca), triclinic (P1) and monoclinic (P2_1/c) crystal systems, respectively. Their X-ray crystal structure determination revealed the presence of non-covalent cation-to-anion (C-H···O_(anion) hydrogen bonds), anion-to-cation (anion···p interactions) and cation-tocation (C-H···p and p···p stacking interactions) interactions. Interestingly, a detailed packing analysis has shown the presence of rare chains of cyclic water hexamers (chair form) and tetramers, stabilized by O-H···O and C-H···O hydrogen bond interactions in the supramolecular complex [Co(phen)_3] S_4O_6·7H_2O (2).