Structural diversity of 9,10-phenanthrenequinone molecular complexes with metal halides

A series of metal halide complexes with 9,10-phenanthrenequinone (PQ) have been synthesized and characterized in detail. An interaction of PQ with metal halides leads to molecular complexes with general formula (PQ)•MXn (MXn = ZnI2, CdI2, HgBr2, InI3). The molecular structures of these complexes have been established by single-crystal X-ray analysis. The metal type determines the resulting molecular structure: the reaction product of PQ with ZnI2 is neutral mononuclear complex ((PQ)•ZnI2 (1) or (PQ)2ZnI2 (2) depending on the synthesis conditions), CdI2 produces with PQ a 1D-coordination polymer [(PQ)•CdI2]n (3), HgBr2 coordinates two PQ ligands with the formation of (PQ)2HgBr2 (4) while indium complex with PQ has an ionic nature [(PQ)2InI2]+[InI4]− (5). The instant reduction accompanies the reaction of PQ with MgI2 and GaI3; unstable monoradical species (PSQ)MgI and (PSQ)GaI2 (where PSQ is an anion-radical of PQ) have been detected using EPR spectroscopy.