Phosphine complexes platinum

Sulfur dioxide and carbon disulfide react with bis(bulky phosphine)platinum complexes to give monomeric trigonal planar [Pt(PR3)2(S02)] and trimeric complexes such as [Pt3(/u-S02)(PR3)2] and [Pt3(/i-CS2)(PR3)2] where R = Cy or But70 71... 

Working with polymethyl methacrylate, Sirdesai and Wilkie (36) have shown that certain phosphine-platinum complexes undergo oxidative insertion reactions and thus catalyze crosslinking leading to flame retardance. This catalyst is expensive and not particularly efficient, but serves as a lead. 

The mechanistic study on the hydrophosphination of activated olefins, in conjunction with rapid inversion of the configuration at the phosphorus center, was elaborated to develop asymmetric hydrophosphination catalyzed by a chiral phosphine platinum complex although the % ee is not excitingly high yet (Scheme 9) [15]. 

Other S2N2 compounds containing divalent sulfur have been obtained by photolysis of (CF3S)3N and by treatment of tertiary amines with sulfur dichloride/ the products from the latter being of interest as fungicides and corrosion inhibitors. Platinum complexes of S2N2 have been prepared by treatment of phosphine-platinum complexes with S4N4/ and a copper (II) complex has been obtained. 

Extensive studies of the asymmetric hydrosiiyiation of prochiral ketones have been performed using rhodium(I) complexes with chiral phosphine ligands and nitrogen ligands " , although the first studies of asymmetric hydrosiiyiation of ketones used chiral phosphine-platinum complexes . ... 

Bis (triorganosilyl) bis (phosphine)platinum complexes 1,2-Disilylation of carbon-carbon multiple bonds... 

An MlP-catalyzed ene reaction between a diketone and an alkene was used to further investigate this phenomenon. The most easily accessible binding sites of an MIP-containing chiral phosphine platinum complexes were poisoned by using diamine derivatives of binaphthol (i.e., 2,2 -diamino-l,l -binaphthalene BINAM) to block access to the substrate (Scheme 20)." ... 

ROP of 1,3-silacyclobutanes may be initiated thermally or catalytically. Most effective transition metal catalysts are hexa-chloroplatinic add, H2PtCl6, platinum metal, and platinum and rhodium complexes (eqn [43]). Polymerization of silacy-dobutanes is accompanied by dimerization, which is the dominant process in the presence of phosphine-platinum complexes. ... 

Phosphine platinum complexes give active hydroformylation catalysts and both terminal and internal alkenes can be hydroformylated by selectively employing platinum-diphosphine complexes, often activated by an excess of tin chloride as the cocatalyst [25,26]. The combination of platinum chloride andtin(II) chloride leads to the formation of the trichlorostannate anion, which presumably acts as a weak coordinating anion, as tin-free catalyst systems have also been reported [27]. The group of Vogt found that the preformation of the catalyst also proved to be effective with only one equivalent of the tin source [28]. 

G. Keglevich, A. Szekrenyi, A. Szollosy, L. Drahos, Synthesis of bis(phosphonatomethyl)-, bis(phosphinatomethyl)-, and bis(phosphinoxidomethyl)amines, as well as related ring bis(phosphine) platinum complexes, Synth. Commun. 41 (2011) 2265-2272. 

Bergamini P, Bertolasi V, Marvelli L et al (2(X)7) Phosphinic platinum complexes with... 

Figure 3.80 Phosphine ligands forming the 5-coordinate palladium and platinum complexes.

The generalized application of the aminolysis of halophosphanes has been the method of choice for the preparation of a wide variety of chiral phosphinous amides by starting from enantioenriched primary amines [36]. The aminolysis reaction occurs efficiently even when the halophosphane is placed in the coordination sphere of a metal, as in the palladium and platinum complexes of the type ds-M(Ph2PCl2)2Cl (M=Pd, Pt) [37,38]. 

Schemes 6-18 A plausible mechanism of hydration of acetonitrile catalyzed by unhindered hydridobis(phosphine)platinum(II) complexes...

The discussion of the activation of bonds containing a group 15 element is continued in chapter five. D.K. Wicht and D.S. Glueck discuss the addition of phosphines, R2P-H, phosphites, (R0)2P(=0)H, and phosphine oxides R2P(=0)H to unsaturated substrates. Although the addition of P-H bonds can be sometimes achieved directly, the transition metal-catalyzed reaction is usually faster and may proceed with a different stereochemistry. As in hydrosilylations, palladium and platinum complexes are frequently employed as catalyst precursors for P-H additions to unsaturated hydrocarbons, but (chiral) lanthanide complexes were used with great success for the (enantioselective) addition to heteropolar double bond systems, such as aldehydes and imines whereby pharmaceutically valuable a-hydroxy or a-amino phosphonates were obtained efficiently. 

More recently, Atwood et al. developed a platinum complex of a water-soluble, bidentate phosphine ligand, cA-(TPPTS)2PtCl2 [TPPTS = tris(sodium m -benzenesuI onatc)phosphi nc, as an effective hydration... 

Platinum(O) phosphine complexes undergo a variety of oxidative addition reactions with compounds containing Group 14 elements. These reactions are of widespread interest because similar processes are probably involved in the catalysis by platinum complexes of reactions such as the hydrosilation of alkenes and the disilylation of dienes and alkenes. 

Chiral bis-phosphine acylplatinum complex 210 with a strong acid such as TfOH serves as an effective enantio-selective catalyst for aldol-type reactions of aldehydes with ketene silyl acetals (Equation (127)).486 The presence of water and oxygen in the catalyst preparation step is required to obtain the highly enantioselective catalyst. The intermediacy of a C-bound platinum enolate was suggested by IR and 31P NMR spectroscopies. 

To realize milder reaction conditions, modification of the platinum catalyst system has been examined. A combined use of bis(catecholato)diboron with phosphine-free divalent platinum complex, PtCl2(cod), allows the diboration of alkynes to proceed at RT.42 The room-temperature diboration has also been achieved with a Pt(nbd)3-monophosphine (Pt/L= 1/1) catalyst.43... 

Diboration of alkene is catalyzed by Pt(0),42,48-51 Rh(i),52-57 Au(i),52 and Ag(i)58 complexes. Phosphine-free platinum complexes such as Pt(dba)2 and Pt(cod)2 are efficient catalysts for diboration of alkene, whereas those with phosphine ligands show much lower catalytic activities (Equations (3) and (4)).48,49 A PtCl2(cod) complex, which may be readily reduced to Pt(0) species with diboron, also catalyzes the addition of bis(catecholato)diboron to alkenes.42 Platinum-catalyzed diboration has so far been limited to terminal alkenes and strained cyclic alkenes. 

Rhodium (I) complexes of chiral phosphines have been the archetypical catalysts for the hydrocarbonylation of 1-alkenes, with platinum complexes such as (61) making an impact also in the early 1990s[1461. More recently, rhodium(I)-chiral bisphosphites and phosphine phosphinites have been investigated. Quite remarkable results have been obtained with Rh(I)-BINAPHOS (62), with excellent ee s being obtained for aldehydes derived for a wide variety of substrates1 471. For example, hydroformylation of styrene gave a high yield of (R)-2-phenylpropanal (94% ee). The same catalyst system promoted the conversion of Z-but-2-ene into (5)-2-methylbutanal (82% ee). 

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