Isocyanide and Phosphine Oxide Coordination in Binuclear Chromium Pacman Complexes

The new binuclear chromium Pacman complex [Cr2(L)] of the Schiff base pyrrole macrocycle H4L has been synthesized and structurally characterized. Addition of isocyanide, CNR (R = xylyl, tBu), or triphenylphosphine oxide donors to [Cr2(L)] gives contrasting chemistry with the formation of the new coordination compounds [Cr2(μ-CNR)­(L)], in which the isocyanides bridge the two Cr­(II) centers, and [Cr2(OPPh3)2(L)], a Cr­(II) phosphine oxide adduct with the ligands exogenous to the cleft.