Potential rhodium and ruthenium carbonyl complexes of phosphine-chalcogen (P-O/S/Se) donor ligands and catalytic applications

Palladium complexes of heterobidentate ligands: Active catalysts for direct acylation of aryl halides with aldehydes via C(sp 2 )-H activation

“…Heterobidentate ligands like a and b tend to show hemilability at the metal centre by dissociating the weaker bond during the catalytic cycles to step up the oxidative addition [27][28][29]. In our continued efforts [30][31][32][33][34][35][36][37][38][39] different coupling reactions, herein, we report synthesis and characterization of two palladium complexes of heterobidentate P-S ligand systems, and their catalytic activity towards acylation of aryl halides with aldehydes.…”

Transition-metal complexes of group 12 with 1,1′-bis(phosphanyl)ferrocene ligands

“…The main reason for the popularity of these ligands is the relative ease of altering the steric and electronic properties of the ligand by changing the substituents on the P-donor atoms. Among the wide variety of ferrocene derivatives, ferrocene diphosphines functionalized with chalcogen donors, such as oxygen, sulfur and selenium, with different -acceptor strengths, form a variety of metal complexes due to their different bonding abilities (Dutta & Deb, 2011;Bishop et al, 1971;Pilloni et al, 1993Pilloni et al, , 1995Pilloni et al, , 1997Pilloni et al, , 1998Cauzzi et al, 1997Cauzzi et al, , 1999Necas et al, 2001;Gimeno et al, 1995;Š tě pnička et al, 2011;Fang et al, 1995;Yeo et al, 1999;Zhang & Hor, 2011;Swartz & Nataro, 2005;Blanco et al, 2006;Kahn et al, 2009;Aguado et al, 2005;Henderson & Alley, 2002;Gimeno & Laguna, 1999). Oxygen being a 'hard' donor is capable of stabilizing metal ions in higher oxidation states due to the absence of d back bonding.…”

“…The metal-oxygen bond is weak ISSN 2053ISSN -2296 and may dissociate reversibly to generate a vacant site for substrate binding and such ligands are called 'hemilabile'. The M-E (E = S, Se or O) bonds are more labile than the M-P bonds which allows the facile generation of a 'vacant site' at the metal centre; this results in interesting stereochemistries and the activation of small molecules for further reaction with other organic substrates (Dutta & Deb, 2011). Bis-phosphine monooxides (BPMOs) of the general formula R 1 R 2 P-Fc-P(O)R 3 R 4 (where Fc = ferrocene) constitute one of the most important classes of hemilabile ligands (Bader & Lindner, 1991;Slone et al, 2007).…”

Evaluation of Organoselenium Based Compounds as Co‐Catalysts in Rhodium‐Catalyzed Hydroformylation

“…[10] Evidence was given that selenium encourages oxidative addition reactions. From these studies it was concluded that these co‐catalysts remain coordinated to the metal center during the catalytic reaction, whereby the P=Se unit is considered as a hemilabile ligand …”