Photoinduced Face-Inversion of Conjugated Tetraene Ligands on a Pd−Pd−Pd Moiety MurahashiTetsuro HiguchiYutaka KatohTetsuya KurosawaHideo 2002 The linear sandwich tripalladium complexes [Pd<sub>3</sub>{Ar(CHCH)<sub>4</sub>Ar}<sub>2</sub>[BAr<sub>f</sub>]<sub>2</sub> (Ar = Ph, <i>p</i>-<i>t</i>-Bu-C<sub>6</sub>H<sub>4</sub>, <i>p</i>-styryl-C<sub>6</sub>H<sub>4</sub>) undergo photoinduced isomerization involving face-inversion of the tetraene ligands. Irradiation of these complexes with visible light (>510 nm) resulted in rac (staggered sandwich) to meso (eclipsed sandwich) isomerization. The structures of rac and meso isomers are determined by X-ray crystallographic analyses.