Complexes of tricyclohexylphosphine

The distribution of the catalyst depends on the choice of the non-polar solvent and on the ligand used. With cyclohexane and the alcohols the palladium complexes of tricyclohexylphosphine and triphenylphosphine are located in the polar phase, with p-xylene the complex of triphenylphosphine is dispersed in both phases, and the complex of tricyclohexylphosphine can be predominantly found in the non-polar phase. Because of the low solubility of... 

To investigate the use of a non-polar catalyst phase and a polar product phase EC, PC and acetonitrile were chosen as polar solvents and cyclohexane and p-xylene as non-polar solvents. Tricyclohexylphosphine, triphenylphos-phine and bisadamantyl-n-butyl-phosphine were used as the ligand for Pd(acac)2. If cyclohexane is used as the non-polar solvent, the palladium complexes of tricyclohexylphosphine and triphenylphosphine are situated in the polar solvent and with p-xylene the complex of tricyclohexylphosphine is located in the non-polar phase, hi the solvent system EC/cyclohexane the palladium complex of bisadamantyl-n-butyl-phosphine can be found in the cyclohexane phase. 

A closer look on the history of the development of catalyst 52 shows that this class of compounds was to some degree predestined for the application of NHCs. Complex 51 containing triphenylphosphines is an active catalyst for olefin metathesis. However, the substitution of the triphenylphosphines by more electron-donating and sterically more demanding tricyclohexylphosphines is accompanied by a significantly increased stability and catalytic performance " Thus, complexes of type 53 58,2S5 logical development with respect... 

Significant advances in organonickel chemistry followed the discovery of frtzws,fraws,fraws-(l,5,9-cyclododecatriene)nickel, Ni(cdt), and bis(l,5-cycloocta-diene)nickel Ni(cod)2 by Wilke et. al.1 In these and related compounds, in which only olefinic ligands are bonded to the nickel, the metal is especially reactive both in the synthesis of other compounds and in catalytic behavior. Extension of this chemistry to palladium and to platinum has hitherto been inhibited by the lack of convenient synthetic routes to zero-valent complexes of these metals in which mono- or diolefins are the only ligands. Here we described the synthesis of bis(l,5-cyclooctadiene)platinum, tris(ethylene)-platinum, and bis(ethylene)(tricyclohexylphosphine)platinum. The compound Pt(cod)2 (cod = 1,5-cyclooctadiene) was first reported by Muller and Goser,2 who prepared it by the following reaction sequence ... 

The synthesis of a ruthenium catalyst in a one step procedure is shown in Figure 1.8. A dimer complex of cymene, i.e., 4-iso-propyltoluene) and RuC is reacted under inert atmosphere with tricyclohexylphosphine and 3,3-diphenylcyclopropene in benzene... 

Reaction (21) occurs with cyclohexene and both cis- and trans-2-butene, without isomerization of the alkenes,139 while the reduction of Ni(acac)2 with Al(alkyl)3 in the presence of PCy3 and 2-butene (cis and trans) affords the complex bis(tricyclohexylphosphine)(l-butene)nickel(0)>... 

Sulfine complexes of platinum(II) can be formed by oxidative addition to Pt(PPh3)3. The initial step involves the formation of an rj2-CS complex which undergoes intramolecular oxidative addition of a C—S bond (equation 542).1869 Use of Pt(cod)2 and PCy3 gives the tricyclohexylphosphine analogue.1870 The reaction gives two stereoisomers.1871 The coordination stabilization of sulfines allows their synthesis in the coordination sphere of platinum, but the cyclic process is not very efficient.1872... 

Tricyclohexylphosphine Complexes of Ruthenium, Rhodium, and Iridium and Their Reactivity Toward Gas Molecules... 

Notes. (1) Pyridine was stored over potassium hydroxide and distilled immediately before use. The tris(cyclohexyl)phosphine-carbon disulphide complex is prepared by the method of K. Issleib and A. Brack.9 This involves the addition of carbon disulphide to an ethereal solution of tricyclohexylphosphine, the precipitate is washed with light petroleum (b.p. 50-60 °C), and recrystallised under a nitrogen atmosphere from either methanol, ethanol or dioxane the complex has m.p. 118 °C. 

Stable dihydride complexes of Pd and Pt have been isolated from the reaction of tricyclohexylphosphine with the metal acetylacetonates and aluminium alkyls.28 The pale yellow [PdH2(PCy3)2] has a trans structure from i.r. and n.m.r. studies, with v(Pd—H) occurring at 1740 cm-1. 

Two-coordinated 14-electron complexes of Pt, Pt(PR3)j, are sources of Pt(0). Preparation of Pt[P(CjH,)3]2 and Pt[PMe(Bu-t)2]2 proceeds from Pt(COD)j (COD = 1,5-cyclooctadiene) with 2 equivs of the tertiary phosphine. Both complexes are air sensitive and dissolve in organic solvents however, Pt[PMe(Bu-t)2]2 decomposes after a few days when stored as a solid under Nj. Bis(tricyclohexylphosphine)Pt in toluene reacts rapidly with at RT to give white crystals of trans-Hj[P(CjH,)3]2Pt. 

A convenient route to a synthetically useful ruthenium polyhydride complex is the reaetion of Ru (COD) (COT) with 2 equiv. of tricyclohexylphosphine under hydrogen ... 

A new preparation of catalytically active ruthenium-carbene complexes can avoid difficulty by using accessible starting materials such as (PhjPjjRuClj and carbene precursors (e.g., diazoalkanes and diphenylcyclopropenes). It involves reduction of RuCl3 3H20 in THF Mg/ClCHjCHjCl in the presence of tricyclohexylphosphine under hydrogen at 60-85° which is followed by cooling to -40° and addition of a 1-alkyne along with a small amount of water. 

Bedford and co-workers have demonstrated that palladium complexes of the simple, inexpensive tricyclohexylphosphine display very high activity in the Stille coupling of non-activated and deactivated aryl chlorides [Equation (5.3.6)]The use of K3PO4 is necessary to promote the coupling. 

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