Complexes of dimethylphenylphosphine

Figure 2.91 Structural data for iridium(III) complexes of dimethylphenylphosphine.

Where X is phenyl, the result of irradiation (sunlight, mercury lamp) is the formation of Ru(NO)X3(PPh3)(OPPh3) (X = Cl, Br) in the case of the diethyl-phenylphosphine complex, irradiation causes isomerization to the cis,mer-isomer. The frans,mer-isomer is the usual synthetic product, but in the case of dimethylphenylphosphine the/ac-isomer was obtained using short reaction times it isomerized to the usual mer,trans-isomer on heating [123],... 

TaCl593 reacted with metallic sodium in neat trimethylphosphine to give the phosphinocarbene tantalum complexes 100 and 101, respectively. These reactions are the first examples of double activation of coordinated trimethylphosphine via oxidative cleavage of a substituent methyl C-H bond. A similar process was also observed in the reduction of tantalum pentabrom-ide with magnesium turnings in the presence of dimethylphenylphosphine.94... 

Cationic methylplatinum(II)-nitrile complexes of the type m is-PtMeL2(NCR)+X have been isolated by the reaction of //vms-PtMeClL2, where L = dimethylphenylphosphine or trimethyl-arsine, with an aryl nitrile and AgX, where X = BF4, PF. Use of pentafluorobenzonitrile and 2,3,5,6-tetrafluorotetraphthalonitrile in alcohol has led to the synthesis of a series of imino ether complexes. A mechanism for imino ether formation, involving nucleophilic attack by an alcohol at a coordinated nitrile, is suggested and the course of the reaction is shown to be dependent not only on the alcohol but also on the size of the anion used.110... 

This procedure has also been utilized for the preparation of the dimeric complexes of this type with the following tertiary phosphines tri-n-butylphosphine, dimethylphenylphosphine, dicyclohexylphenylphosphine, and triphenylphosphine. Satisfactory yields ranging from 50 to 80% were obtained in all cases. 

Iron(III) complexes of reduced hemes have been claimed to stabilize the dxzAyz) Axy) ground state much more readily than iron porphyrinates. However, in some cases this may be more a result of the choice of axial ligands than to the electronic nature of the reduced heme ligand. It is now clear that iron(III) chlorins, when bound to imidazole,dimethylphenylphosphine or aliphatic amine ligands, have the same electronic ground state as iron(III) porphyrins, that is, dxy) dxzAyzf whereas when bound to cyanide a somewhat different... 

Although a general route for the preparation of carbonylhalobis((ert-phosphine)-iridium(I) complexes has been reported, it is somewhat inconvenient for complexes of highly basic ligands (e.g., trimethyl- or dimethylphenylphosphine), since the two-step sequence required and the high solubility of the products (particularly for the P(CH3)3 complex) result in low yields. A more effici-... 

The reaction of the zero-valent osmium complex Os(CO)3(PPh3)2 with a series of strong acids (HX) has produced cationic hydrido-species of the type [Os(H)(CO)3(PPh3)2]X, where X = Br-, CIO4-, BF4-, or PF -. The complexes behave as 1 1 electrolytes in nitrobenzene and may be reconverted to the zerovalent complex on the action of base. Ammonia and primary amines (A) react with complexes of the type [MX3(PR3)3], where M = Os or Ru, in ethanol at 20 °C to form the M" species mer-[MX2(A)(PR3)a] and acetaldehyde. Secondary and tertiary amines with dimethylphenylphosphine ligands also cause reduction, but in this case the product is an alcohol complex. The reduction is considered to occur via formation of a hydride complex since some hydrogen is formed in all reactions and steric factors probably control whether an amine or an alcohol complex is formed. 

The (-)-enantiomer of sparteine is obtained from natural sources as a commercially available and relatively inexpensive oil. The metallation of 1 with n-BuLi in hexane, in the presence of (-)"Sp, produced the a-carbanion 2 which was subsequently quenched affording the known phosphine oxide 3 in approximately 14% ee. Although it has been suggested that the low stereoselectivity is due to the disruption of the (-)-sp/BuLi complex by complexation of the oxygen atom to the lithium cation, the same reaction with unprotected dimethylphenylphosphine provides completely racemic products. Due to the low enantioselectivity, this method was initially ignored in phosphorus chemistry until a seminal paper of Evans and co-workers in which they described similar reactions with phosphine boranes and sulfides. In this case, the enan-tioselectivities were much higher and the method could be successfully applied... 

An unusual cobalt-dioxygen adduct is formed in the reaction of O2 with [Co -(CN)a(PMe2Ph)3], in that during the course of reaction a dimeric complex is formed with the exclusion of only a single mole of dimethylphenylphosphine. The rate law of the form... 

Chatt J, Kubota M, Jeffery Leigh G, March FC, Mason R, Yarrow DJ (1974) A possible carbon dioxide complex of molybdenum and its rearrangement product di-p-carbonato-bis carbonyltris(dimethylphenylphosphine) molybdenum X-ray crystal stmcture. J Chem Soc... 

Other halides can be introduced by metathesis. Figure 2.55 summarizes some of the complexes isolable with dimethylphenylphosphine, similar in general to the corresponding iridium complexes (section 2.13.3), including the photochemical isomerization of the mer-isomer. 

Two papers have appeared on the reactions of halogenophosphines with tervalent phosphorus compounds. In a detailed study of the reactions at 20 °C of a range of tertiary phosphines with phosphorus trichloride, dichlorophenylphosphine, and chlorodiphenylphosphine, it has been shown that, in general, 1 1 adducts are formed, provided that the tertiary phosphine is a good nucleophile. With diphenylchlorophosphine, for example, an adduct (18) is formed with dimethylphenylphosphine, but not with diphenylmethylphosphine, although the relative importance of steric and electronic factors remains to be established. The related reactions of phosphorus trichloride and of dichlorophenylphosphine are much more complex, and the initial crystalline products are not amenable to analysis. The reactions at 280 °C of a similar system have been shown to lead to halogen exchange, e.g. the conversion of (19) to (20). 

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