Subject tertiary phosphines

RM can be a traditional Grignard reagent or an organolithium, 2inc, aluminum, or mercury compound. The Grignard route is employed commercially for production of tertiary phosphines, even though these reactions are subject to side reactions. Yields are often low, eg, 40—50% for (C4H )2P prepared via a Grignard reaction (18). A phosphoms—carbon bond can form from the metathetical reaction of a phosphoms haUde and a pseudohaUde salt. 

In addition to the tertiary phosphine complexes, a few others such as Pt(QBu3)4 (Q = As, Sb) and Pt(QPh3)4 have been made, but they have been the subjects of few studies. 

Bis-ylides (Scheme 31) may function as four-electron donors and become geminally diaurated. The donor capacity of ylides is generally higher than that of most other ligands, and even powerful donors like tertiary phosphines can thus be readily replaced by non-stabilized ylides. Ylides may therefore be used as auxiliary ligands which are retained, while other components of the coordination sphere are subject to substitution. 

The Michaelis-Arbuzov reaction is the most used and well-known method for the synthesis of phosphonates and their derivatives and may also be used to synthesize phosphinates and tertiary phosphine oxides. The simplest form of the Michaelis-Arbuzov reaction is the reaction of a trialkyl phosphite, 3, with an alkyl halide, 4, to yield a dialkyl alkylphosphonate, 6, and new alkyl halide, 7 (Scheme 2). During this transformation the phosphorus atom of a ter-valent phosphorus(III) species (3) acts as a nucleophile resulting in the formation of an intermediate alkoxy phosphonium salt 5, containing a new [P—C] bond. The precise structure of the intermediates 5 is a subject of debate—as reflected by common reference to them as pseudophosphonium salts —with a penta-coordinate species (containing a [P—X] bond) being proposed and detected in some cases.18 Decomposition (usually rapid under the reaction conditions) of the intermediate 5 by nucleophilic attack of X- on one of the alkyl groups R1, with concomitant formation of a [1 =0] bond yields the product pentavalent phosphorus(V) compound (6) and the new alkyl halide, 7. 

Quaternary phosphonium salts are organophosphorous compounds used as Wittig olefination reagents, phase transfer catalysts, electrolytes, ionic liquids, and as surface active reagents. Their preparation involves the C-P bond formation in tertiary phosphines. We envisaged that addition of phosphines to unsaturated compounds should be preferable as compared to the conventional method using a substitution reaction of organohalogen compounds (Scheme 1). In this chapter, we describe our recent study on this subject. 

Holm and co-workers have developed a significant OAT model based on complexes of L-NS2 it has been extensively documented in the literature (129, 130, 206-210) and has been the subject of a number of reviews (7, 211, 212). We therefore limit our discussion to the key features. Five-coordinate (L-NS2)Mo02 (33, Fig. 10a) reacts with tertiary phosphines to form a purple compound (45), formulated as (L-NS2)MoO(dmf) (Eq. (17)) this reaction is bimolecular but slower... 

Functionalized tertiary phosphines continue to attract considerable interest for their unusual coordination chemistry and their increasing importance in catalysis. Whilst this subject area is extensive, only a few types of functionalized phosphines will be discussed here, including brief details regarding preparative procedures. 

The monoxide of bisdiphenylphosphinomethane forms the salt (117) on being subjected to the Horner reaction with bromobenzene in refluxing benzonitrile in the presence of nickel(n) chloride. Tertiary phosphines react with the u-halogenobenzaldimines (118) (and related u-bromodiarylazo-compounds) under unusually mild conditions (refluxing ethanol) in the presence of nickel(n) bromide as catalyst, with formation of the arylphosphonium salts (119). Only... 

This topic was the subject of the occasional review in last year s volume. " Pulsed electron beam high energy source pressure mass spectrometry has been used in combination with photoelectron spectra to determine the gas-phase basicities of methyl and phenyl tertiary phosphines and also primary phosphines. Fragmentation patterns in the mass spectra of various phosphanes, cyanophosphines, and the naphthyldiphosphine (90) have been described. 

The mixed tertiary phosphines are obtained by subjecting mixed tetra-alkylphosphonium compounds to dry distillation ... 

Looking to the future, it seems that tertiary phosphines will be the subject of intensive studies, especially in their range of application as ligands for metal complex catalysts. The most interesting opportunities lie in the development of the application of reagents and catalysts, allowing us to obtain tertiary phosphines by the most accessible methods. It is believed that the area of the application of tertiary phosphines will be expanded greatly. 

Red platinum-triangle carbonyl derivatives of the type (R3P) i Pt3 (CO) 3, presumably 84 (M = Pt), may be prepared by carbonylation of K2PtCli in the presence of the tertiary phosphine R3P, carbon monoxide, and hydrazine, or by reaction of the polymeric platinum carbonyl [Pt(CO)2ln (conceivably an uncharacterized platinum cluster) with the tertiary phosphine (33, 34, 53). These trimetallic platinum clusters (R3P)ijPt3-(CO)3 are unstable when subjected to reaction with Ccurbon monoxide to give the tetrametallic derivatives (R3P)ijPtij (CO) 5 (p. 416) the rate of this reaction increases with increasing basicity of the tertiary phosphine R3P. 

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