The electrochemical behaviour of [Co(sep)]3+ bound with p-sulfonatothiacalix[4]arene and tetracarboxy-p-sulfonatocalix[4]arene in correlation with inclusive and non-inclusive binding modes

Cobalt(iii) sepulchrate complexes: application as sustainable oxidative catalysts

“…Interestingly, careful searches in the literature and in the Cambridge Structural Database (CSD, Version 5.34 2013) 52,53 reveal that despite the considerable number of studies involving metal complexes with sep ligands the number of crystal structures with this organic molecule is very low (only twelve entries were found). 24,26,[54][55][56][57][58][59][60][61] The crystal structure of the compound [Co(sep)] 2 (SO 4 ) 3 10H 2 O was determined to belong to the centrosymmetric monoclinic space group C2/c, with the asymmetric unit (asu) comprising one cationic complex [Co(sep)] 3+ , one and a half sulphate anions and five crystallization water molecules (Fig. 1).…”

“…As characteristic of most of the transition metal complexes with the sep ligand, the Co(III) centre coordinates to the six N-atoms of the NH groups, ultimately giving rise to a slightly distorted octahedral 2). 24,[56][57][58][59][60][61] The [Co(sep)] 3+ complexes are surrounded by sulfate anions and numerous crystallization water molecules, being involved in an extensive inter-molecular hydrogen bonding network (Fig. 2).…”