The synthesis and characterization of the octahedral Co(III) complex of a pyrrolopyrrolizine derivative formed with dicyanovinylene-bis-(meso-aryl)dipyrrin

A low spin state and diamagnetic Co(III) complex 1 possessing pyrrolopyrrolizine ligands formed with dicyanovinylene-bis-(meso-aryl)dipyrrin was synthesized via the thermally activated metalation with CoCl(2) and isolated via column chromatography. The nuclear magnetic resonance of complex 1 revealed diamagnetism, thereby confirming the structure of the octahedral Co(III)-complex of strong-field ligands. The resulting molecular structure of 1 was elucidated by the X-ray diffraction analysis. An arrangement of two pyrrolizine-ligands for the metal chelation was found in the AB–BA order, which was distinct from the case observed during the formation of bis-Ni(II)-expanded porphyrinoids.