On the Dynamic Behavior of Pacman Phosphanes─A Case of Cooperativity and Redox Isomerism

Abstract

In solution, the Pacman chlorophosphane (2Cl) shows fast exchange of the endo/exo-orientation of the two P−Cl bonds in the molecule featuring cooperativity. Experimental and quantum mechanical investigations of the inversion on the phosphorus(III) centers reveal a crucial role of chloride ions in the dynamic process. To confirm the results, the homologous Pacman halogen-phosphanes 2X were prepared by halogen exchange reactions (X = F, Br, and I). Besides accelerated dynamic behavior for the heavier analogues, significant differences in the molecular structure are caused by the halogen exchange reactions, including the formation of an endo−endo substituted Pacman fluorophosphane as well as dicationic species by phosphorus halogen bond dissociation. The latter process can be regarded as redox isomerism since two P III atoms in 2X become P V centers in the dications.

Monofluorophos–Metal Complexes: Ripe for Future Discoveries in Homogeneous Catalysis

“…Ligand L32 generates Rh catalysts for alkene hydroformylation with l:b ratios ranging from 0.41 to 12.8 depending on ligand concentration and the nature of R [96]. Chelating bis(monofluorophos) ligands would be an exciting avenue to explore and an example of a bis{N,N}PF ligand was recently described: the "Pacman" fluorophos ligand L33 (see Figure 7) [97].…”