Résumé
The reactivity of both the monoanionic and dianionic forms of bis(diphenylthiophosphinoyl) methane (2(-) and 2(2-)) as well as the dianion of tetraisopropyl methylenediphosphonate (3(2-)) was investigated towards the same Co-II precursor CoCl2. Monoanion 2- coordination yields a homoleptic zwitterionic Co-II complex. However, both dianions (2(2-) and 3(2-)) give the same overall structure with a square Co2C2 core. Structures of all of the complexes have been confirmed by full NMR spectroscopic analysis and X-ray diffraction. Furthermore, DFT calculations have been carried out to rationalize the stability of such species.