Phosphides ligands

Dimeric zinc complexes of tertiary phosphines, [Zn(PR3)I2]2, are also formed from zinc powder and R3PI2, (R = Me, Et, n-Pr, ra-Bu). The crystal structure of the ethyl derivative demonstrates the dimeric nature of the complexes.295 Metallation of diphenylphosphine with ZnEt2 results in a trimeric species with a Zn3P3 core and bridging diphenyl phosphide ligands. Two protic (HPPh2)... 

The more sterically demanding phosphide KPH(mes ) crystallizes solvent-free, even from solutions containing THF, as the ladder polymer [K PH(mes ) ]x (25) (72). Coordination about each K atom is completed by multihapto interactions (approximately if ) between the cation and the mesityl ring of an adjacent phosphide ligand. A... 

Bun, Bus, Bu1) (99). The complex with R = Me crystallizes as the THF solvate [MeCu(PBu2)Li(THF)3] in which the phosphide ligand bridges the two-coordinate Cu and four-coordinate Li centers. These cuprates were found to be more thermally stable than other phosphido(alkyl)-cuprates but less reactive toward electrophiles than related cyanocu-prates. 

The term phosphide ligand for the P ligand corresponds to the lUPAC guidelines. Hitherto this name has often been used incorrectly for R2P ligands... 

HCHO and PH3 proceeds in the presence of K2PtCl4 at room temperature and affords the crystalline product in an essentially quantitative yield in 2.5 h [4]. Palladium compounds are also active in the catalysis [5]. In these reactions the active species is believed to be zero valent. Two mechanistic possibilities have been proposed as illustrated in Scheme 2. The first elemental process involved in the catalytic cycle is oxidative addition of a P-H bond, which is well precedented [6]. In one of the mechanistic possibilities the processes that follow the oxidative addition are the insertion of the C=0 bond into H-M species and P-C reductive elimination, the latter of which is also precedented [7]. In the other, the coordinating phosphide ligand makes a nucleophilic attack [8] at the formaldehyde carbon forming zwitterionic species. 

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