Ring-whizzing in polyene-PtL(2) complexes revisited

Ring-whizzing was investigated by hybrid DFT methods in a number of polyene–Pt(diphosphinylethane) complexes. The polyenes included cyclopropenium(+), cyclobutadiene, cyclopentadienyl(+), hexafluorobenzene, cycloheptatrienyl(+), cyclooctatetraene, octafluorooctatetraene, 6-radialene, pentalene, phenalenium(+), naphthalene and octafluoronaphthalene. The HOMO of a d(10) ML(2) group (with b(2) symmetry) interacting with the LUMO of the polyene was used as a model to explain the occurrence of minima and maxima on the potential energy surface.