Observation of a Chloride-Bridged P P Bond in the Phosphorus Cation [L(CI)P(μ-CI)P(CI)L]+ (L = NHC)

A bridging chloride anion between two electrophilic phosphorus centers was observed for the first time in the molecular structure of the novel P-P bonded cation [(L2P2Cl3)-P-DiPP]+ (2(+); L-DiPP = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene). Cation 2(+) is prepared by the reduction of the monophosphorus species [(LPCl2)-P-DiPP](+) (1(+)) with sodium. DFT calculations, AIM and mechanochemical (compliance constants) analyses are used to examine the bonding situation of this unusual species. The monochloro-substituted cation [(L2P2Cl)-P-DiPP](+) (3(+)) was likewise observed as a reduction product of 1(+).