Triphenylphosphine, complexes transition metals

When side reactions do not interfere, the use of alcohol and base conveniently yields metal hydride. Each of the first four reactions in Table 1 prepares a complex transition-metal hydride from a metal salt in a few minutes, but only with triphenylphosphine. 

Some of these ions can complex transition metals, such as the copper(I) complex of B3Hg and triphenylphosphine. 

Pyridazines form complexes with iodine, iodine monochloride, bromine, nickel(II) ethyl xanthate, iron carbonyls, iron carbonyl and triphenylphosphine, boron trihalides, silver salts, mercury(I) salts, iridium and ruthenium salts, chromium carbonyl and transition metals, and pentammine complexes of osmium(II) and osmium(III) (79ACS(A)125). Pyridazine N- oxide and its methyl and phenyl substituted derivatives form copper complexes (78TL1979). 

A very significant recent development in the field of catalytic hydrogenation has been the discovery that certain transition metal coordination complexes catalyze the hydrogenation of olefinic and acetylenic bonds in homogeneous solution.Of these catalysts tris-(triphenylphosphine)-chloror-hodium (131) has been studied most extensively.The mechanism of the deuteration of olefins with this catalyst is indicated by the following scheme (131 -> 135) ... 

The conversion of coordinated NSCI into a nitrido ligand provides a useful synthesis of transition-metal nitrides. For example, treatment of ReCl4(NSCl)(POCl3) with triphenylphosphine generates the nitrido complex ReNClaCPPhsla. "... 

A great variety of suitable polymers is accessible by polymerization of vinylic monomers, or by reaction of alcohols or amines with functionalized polymers such as chloromethylat polystyrene or methacryloylchloride. The functionality in the polymer may also a ligand which can bind transition metal complexes. Examples are poly-4-vinylpyridine and triphenylphosphine modified polymers. In all cases of reactively functionalized polymers, the loading with redox active species may also occur after film formation on the electrode surface but it was recognized that such a procedure may lead to inhomogeneous distribution of redox centers in the film... 

Non-ionic thiourea derivatives have been used as ligands for metal complexes [63,64] as well as anionic thioureas and, in both cases, coordination in metal clusters has also been described [65,66]. Examples of mononuclear complexes of simple alkyl- or aryl-substituted thiourea monoanions, containing N,S-chelating ligands (Scheme 11), have been reported for rhodium(III) [67,68], iridium and many other transition metals, such as chromium(III), technetium(III), rhenium(V), aluminium, ruthenium, osmium, platinum [69] and palladium [70]. Many complexes with N,S-chelating monothioureas were prepared with two triphenylphosphines as substituents. 

Polarographic studies are reported on thioesters, mainly of the type (140) and (141), and on trichloroethylphosphonites. In the field of nucleotides and nucleosides it is found that ATP has a very high surface activity at the mercury electrode, which is strongly dependent upon complex formation with transition metals. The polarographic behaviour of cobalt complexes with triphenylphosphine and its oxide has been studied in order to estimate extraction efficiencies. 

Besides solid transition metals, certain soluble transition-metal complexes are active hydrogenation catalysts.4. The most commonly used example is tris(triphenylphosphine)-chlororhodium, which is known as Wilkinson s catalyst.5 This and related homogeneous catalysts usually minimize exchange and isomerization processes. Hydrogenation by homogeneous catalysts is believed to take place by initial formation of a rc-complex, followed by transfer of hydrogen from rhodium to carbon. 

It occurred to us that ionic interactions might be a highly suitable binding motif to enforce the formation of heterobidentate ligand combinations [48[. The assembly ligand 14 /IS has been formed from the well-known TPPMS (14, monosulfonated triphenylphosphine sodium salt) and 3-(diphcnylphosphinyl)aniline hydrochloride (IS) by a simple ion-exchange reaction (Scheme 10.6). The coordination behavior ofthe ion-pair 14 /I S has been tested with various transition metal complexes. Other... 

All monophosphorus ligands used are meta-substituted triphenylphosphine derivatives. Their structural similarity ensures that they will also have similar binding properties to transition metal central atoms, and the distribution of the complexes will be influenced by the interactions of the functional groups only. 

Hydrides of Pt(II) are the most numerous of any transition metal hydride group. In addition to the presence of the hydride ligand, the complexes invariably have a coordinated phosphine, and synthetic routes to these compounds using both hydridic and protonic reagents have been reported (I). The pure complexes are usually both air stable and kinetically inert. The purpose of this chapter is to show the diversity of hydrides that can be obtained from protonation reactions on zero-valent and di-valent triphenylphosphine platinum compounds, and to rationalize the type and nature of the product formed from the character of the acid HX. 

Cleavage of the H—H bond by transition metal complexes suggests that similar reactions may be possible with C—H and C—C bonds. In fact it has been known for a number of years that coordinated triphenylphosphine can undergo intramolecular cyclomelallation. 

Murai and co-workers reported the silylformylation of aliphatic aldehydes in 1979.116 In this version of the transition metal-catalyzed reaction of HSiR3 and CO with various substrates, a formyl moiety is always present in the final product of the reaction. Murai utilized the Co2(CO)8 complex with a triphenylphosphine cocatalyst to catalytically form a-siloxy aldehydes from aliphatic aldehydes. An excess of reactant aldehyde is required to obtain the formyl products if silane is in excess, l,2-bis(siloxy)olefins are produced.117... 

Attempt to prepare Jt-complexes of triafulvenes and related methylene cyclopro-parenes285,427 428 directly by ligand exchange reaction with transition metal complexes resulted in metal insertion into the sigma bond, forming metallacyclic complexes. Thus reaction of the electron-poor triafulvene l,2-diphenyl-3-dicyanomethylenecyclopropene with (ethylene)bis(triphenylphosphine)platinum in refluxing benzene gave two crystalline products whose platinacyclobutene structure was confirmed by X-ray structure analysis (equation 364)429. 

Although terminal oxo complexes of the late-transition-metal elements have been proposed as possible intermediates for oxidations catalyzed by these elements, late-transition-metal-oxo complexes were scarcely known. Hill and coworkers reported the synthesis and characterization of Pt4 + -, Pd4 + - and Au3 + -oxo complexes, [M(0)(0H2) W0(0H2) (PW9034)2]m (M = Pt, Pd and Au, n = 0-2), stabilized by electron-accepting polyoxotungstate ligands [109-111]. The stoichiometric reaction of the Au-oxo complex [Au(0)(0H2) W0(0H2) 2 (PW9034)2]9 with triphenylphosphine led to the formation of triphenylphosphine oxide. 

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