Unexpected photoisomerization of a pincer-type amido ligand leads to facial coordination at R(IV)

Article abstract of DOI:10.1021/ic052014h

The divalent complex (BQA)PtMe undergoes oxidative addition with MeI to afford the octahedral complex cis-(mer-BQA)PtMe₂I {(BQA)^- = bis(8-quinolinyl)amide}. When this molecule is irradiated with visible light, it isomerizes to (fac-BQA)PtMe₂I, where the BQA ligand adopts an unexpected facial coordination mode. The amide nitrogen in this molecule is sp³ hybridized and can be easily quartemized with HBF₄, resulting in [H(fac-BQA)PtMe₂I][BF₄], with only minor perturbation to the coordination sphere.