Phosphine-pyridyl and related ligands in synthesis and catalysis

Cationic Rhodium Complexes with Hemilabile Phosphine Ligands as Polymerization Catalyst for High Molecular Weight Stereoregular Poly(phenylacetylene)

“…In this context, functionalized phosphines have been intensively studied as hemilabile ligands for soft metal centers because of their ability for providing easily accessible coordination vacancies through a potentially dynamic 'on-and-off' chelating effect for the metal center. 21,22 Heteroditopic ligands of hemilabile character that combine strong electron donors and weak donor functions linked by a flexible backbone, as for example Ph 2 P(CH 2 ) n Z (Z = OR, NR 2 , SR), 23 should allow a dynamic interaction with the metal center, and/or stabilization of polar intermediates in catalytic applications, exerting some directing effect. We have discovered that cationic rhodium(I) complexes containing these hemilabile phosphine ligands, [Rh(diene){Ph 2 P(CH 2 ) n Z}] + , are efficient catalysts precursors for the stereoregular polymerization of substituted PAs.…”

Variable coordination of tris(2-pyridyl)phosphine and its oxide toward M(hfac)2: a metal-specifiable switching between the formation of mono- and bis-scorpionate complexes

“…[1][2][3] The combination of "soft" (P-atom) and "hard" (N-atoms) donor sites in pyridylphosphines makes them very important and versatile ligands for the design of unique catalysts, 4 luminescent materials 5 and prospective drugs. 6 Among pyridylphosphines, tris (2-pyridyl) phosphine (Py 3 P) is gaining a special interest owing to the useful properties of its metal complexes.…”

New Chiral P-N Ligands for the Regio- and Stereoselective Pd-Catalyzed Dimerization of Styrene

“…In particular, hemilable hybrid P-N multidentate ligands are able to stabilize metal ions in a variety of oxidation states and geometries. Indeed, the π-acceptor character of phosphorus atom can stabilize a metal center in a low oxidation state, while the nitrogen σ-donor ability makes the metal more susceptible to oxidative addition reactions, features that can play a crucial role in stabilizing intermediate oxidation states and/or geometries during a catalytic cycle [1]. In addition, the possibility of varying the electronic and steric properties of this kind of ligands allows to obtain potentially multidentate ligands that are able to bind or bridge one or more metal ions affording homo-or hetero-, bi-or polymetallic complexes [1,2].…”

“…Recently, a particular attention has been devoted to diazaphospholidine ligands derived from proline, which have been successfully used in different catalytic processes such as asymmetric coppercatalyzed cyclopropanation [4], iridium catalyzed enantio-and regioselective allylic etherification [7], palladium catalyzed enantioselective allylic amination [1], rhodium-catalyzed asymmetric hydroformylation [25].…”