Metal phosphides synthesis

Heterometallic alkali metal phosphide complexes with transition metals have also been reported. The complex [(Cy2P)3Hf(ju.-PCy2)2Li (DME)] results from the reaction of LiPCy2 with HfCl4(THF) (98). This complex persists in solution. Jones et al. have reported the synthesis and reactivity toward a range of electrophiles of a series of lithium di-t-butylphosphido(alkyl)cuprates [RCu(PBu2)Li] (R = Me,... 

By far the most ubiquitous intermediates in synthesis of this class of phosphines are the alkali metal phosphides which can be prepared by either the KOH/DMSO method, by reaction of tertiary phosphines or chlorophosphines with alkali metals, or in the reaction of BuLi with appropriate secondary or tertiary phosphines. A number of the ligands in Figures 6 and 7 were prepared this way (60-69,72-74). 

The various techniques for the synthesis of transition metal phosphides have been summarized in the monograph by Aronsson, Lundstrom, and Rundqvist.1 The most common method used for the preparation of the phosphides is the direct combination of the elements. However, in general, the products are not pure or... 

These nucleophilic reagents react with most common electrophiles such as organohalides, tosylates, aldehydes, ketones, epoxides, and activated alkenes. It should be noted that many workers have found much higher yields if the phosphides are protected as phosphine oxide or borane anions (see Section 3). Phosphide reagents also react with activated arenes to give mixed aryl phosphines (Protocol 2). Metal phosphides therefore provide an alternative, complementary tertiary phosphine synthesis to the electrophilic routes outlined in Section 2.1. 

So far we have discussed the synthesis of useful P-chiral phosphorus intermediates that can be converted into a variety of phosphines by reaction with a nucleophile (and deprotection). However, Imamoto and co-workers found that one-electron reducing agents react with resolved menthyl phosphine oxides and boranes to give metal phosphides that retain their configuration at phosphorus (Scheme 26).49... 

The cleavage of a P-Ph bond (method (1)) has been widely used to create a variety of phospholide salts. Notably, this methodology has been employed in the synthesis of group 13 phospholyl complexes, which have come to the fore in recent years as potential single source substrates for the preparation of the corresponding metal phosphides by chemical vapor deposition (CVD). This is exemplified by the reaction of lithium 2,5-di(tert-butyl)phospholide with GaBr to afford a Ga(l) polymer 297 (Scheme 101) <1999AGE1646>. Additionally, this synthesis nicely illustrates the use of bulky substituents in the position a to phosphorus to favor -coordination. 

Route (4) for the preparation of phospholyl complexes, namely insertion of diynes into metal phosphide bonds and subsequent cyclization, is the least used approach. However, an alternative synthesis of299 and 300 using this type of methodology has been demonstrated successfully (Scbeme 105) <1996AGE1125>. 

Asymmetric Synthesis by Homogeneous Catalysis Carbonyl Complexes of the Transition Metals Carbonylation Processes by Homogeneous Catalysis Heterogeneous Catalysis by Metals Phosphides Solid-state Chemistry Polynuclear OrganometaUic Cluster Complexes Zeolites. 

Wang X., Clark P. and Oyama S. T., Synthesis characterization and hydrotreating activity of several iron group transition metal phosphides, J. Gated. 208 (2002) pp. 321-331. 

Other chemical routes to metal phosphides include phosphinolysis reactions and reactions bet3veen metallo-organics and P(SiMe3)3 all involve elimination and condensation processes. Buhro [61] reported the synthesis of several binary phosphide semiconductors along with ternary phases (e.g. ZnGeP2), using solution-phase metallo-organic routes. A recent review of the preparation of II/V materials has appeared [63]. 

New synthesis method for metal phosphide hydrotreating catalysts MoP/Si02 and M0P/AI2O3... 

The synthesis and uses of alkali metal phosphides have been reviewed. Alkali metal diphenyl-phosphides are readily obtained by cleavage of a phenyl group from PPh, by lithium in tetra-hydrofuran (THF), sodium or lithium in liquid ammonia or potassium in dioxane (equation 3). The metal-phenyl product can be destroyed by addition of a calculated amount of Bu Cl or NH4X. Usually MPPhj compounds are prepared in situ, but they can be isolated, usually as solvates. These compounds can also be obtained from Ph2PCl and the alkali metal, or from Ph2PH and alkyl-lithium. ... 

Synthesis of sandwich-type metal phosphide with two P5 rings Discovered telomeres arranged themselves into 4-stranded G quadruplexes First synthetic virus created... 

The numerous applications of phosphines include (1) synthetic reagents, (2) ligands in metallo-phosphorus compounds, (3) catalysts, (4) metal deposition agents, (5) electron-rich compounds. Metallophosphines (metal phosphides) types MPR2 and M2PR (M=Li, Na, K) are especially useful in synthesis (Chapter 8.8) (Table 6.8). 

Early studies of metal phosphides were carried out by Pelletier [1] in 1789, and the first metallq)hospho-rus coordination complex (M-P-E type with E=H), was reported by Rose [2] in 1832. The first M-P-E type with E=C was a tertiary phosphine complex made by Hoffmann [3] in 1857. Although this was followed by the synthesis of a few other complexes of this type by Cahors and Gal in 1870, it was not until after the pioneering work of Mann, Chatt [4] and Jensen [5] in the field of organometallic chemistry during the 1930-1960, that the exponential rise of metallophosphorus chemistry was to begin. 

The presence of small quantities of metal phosphides can often profoundly affect the performance of metals, however, and this is sometimes pnt to nse in metallurgy. The fragmentary P units found in some metal phosphide structures are proving to be useful as building blocks in the synthesis of complex carbo and aza-phosphorus componnds. 

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