Palladium(ii) complexes of bis(diphosphene) with different coordination behaviors

Abstract

Organophosphorus compounds possessing the P−P double-bond character are intriguing materials in coordination chemistry because it is possible to form a variety of coordination modes from the π-bond in addition to...

Diphosphene with a phosphineborane tether and its rhodium complex

“…Theoretical calculations showed the dominant contribution of the π* orbital of the PvP bond even in complex 7, and its high electron-accepting character should promote facile ligand exchange reaction with N-donor reagents despite the bidentate coordination of 1. In particular, the reaction of diphosphenerhodium complex 7 with pyridine gave an equilibrium mixture of 7, pyridine, diphosphene-phosphineborane ligand 1, and [Rh( py) 2 (cod)]BF 4 (15) owing to the weak coordination ability of 1 toward rhodium. Although further improvements in the fascinating catalytic activity of the diphosphene-transition metal complexes are required, our fundamental studies on bidentate diphosphene-rhodium complex 7 are expected to contribute to catalytic chemistry in the near future.…”

“…In both reactions, the generated rhodium species could not be sufficiently characterized because rhodium complexes bearing Scheme 3 Reactions of diphosphene-rhodium complex 7 with N-donor reagents. (tmeda = N,N,N,N-tetramethylethylenediamine, cod = 1,5-cyclooctadiene, py = pyridine); K eq = ( [1]• [15])/([7]•[ py] 2 ).…”

“…4c). The equilibrium constant (K eq = ( [1]• [15])/([7]•[ py] 2 ) was estimated to be 1.0(2) mol −1 L −1 by pyridine titration of a CD 2 Cl 2 solution of 7 (Table S1 †). Thus, the coordination ability of 1 is comparable to that of pyridine even though 1 exhibits bidentate coordination.…”

“…Our recently reported η 1 -diphosphene/η 2 -phosphanylphosphido palladium complex G is derived from bis(diphosphene) via chloride migration from palladium to phosphorus. 15 To create a diverse array of diphosphene-transition metal complexes with different coordination environments, unsymmetrical bidentate ligands bearing a PvP bond are of paramount importance. Such ligands should contribute to expanding the organometallic chemistry of diphosphenes through a direct ligand exchange reaction with a suitable precursor of transition metal complexes.…”