Solvent-modulated reversible conversion of a [2 x 2]-grid into a pincer-like complex.

The triazine derived ligand reacts with one equivalent of Co(II) salts to give complexes whose architecture depends on the solvent employed: the [2 x 2]-grid like tetranuclear complex and the pincer-like mononuclear complex, obtained respectively by crystallization from nitromethane and from acetonitrile may be interconverted reversibly, the grid-pincer conversion being markedly accelerated by adding an amine.