Phosphines aromatic

Preparation and Properties of Organophosphines. AUphatic phosphines can be gases, volatile Hquids, or oils. Aromatic phosphines frequentiy are crystalline, although many are oils. Some physical properties are Hsted in Table 14. The most characteristic chemical properties of phosphines include their susceptabiUty to oxidation and their nucleophilicity. The most common derivatives of the phosphines include halophosphines, phosphine oxides, metal complexes of phosphines, and phosphonium salts. Phosphines are also raw materials in the preparation of derivatives, ie, derivatives of the isomers phosphinic acid, HP(OH)2, and phosphonous acid, H2P(=0)0H. 

Ahphatic phosphines can be gases, volatile Hquids, and oils. Aromatic phosphines frequentiy are crystalline, although many are oils. Physical properties of selected phosphines are Hsted in Table 14. 

The crude mixtures all have strong odors of aromatic phosphines. Some of this odor presumably arises from disproportionation of monophenylphosphinic acid to phenylphosphine. It is recommended that manipulations be carried out with rubber gloves to prevent transfer of these rather durable odors to the skin, and that all equipment be washed with a bleach such as Clorox before it is taken from the hood. 

Silanes with electronegative ligands did not react, except in the presence of the tertiary base EtjN [e.g., Eq. (19)] (62, 63). This then provides an attractive route to Si—Pt(II) compounds since the starting materials are readily available and the reaction gives pure products in high (60-90%) yields. Only aromatic phosphine Pt complexes reacted readily, and the use of an excess of silane failed to bring about replacement of the second halogen atom. 

For very electrophilic carbene ligands bound to a metal center which also has coordinated an aromatic phosphine ligand,there is the possibility of the following intramolecular substitution reaction leading to a metallacycle ... 

Finally, quatemization of aromatic phosphines (example 21, Table XI) is exemplified for tetraphenylphosphonium bromide. 

Aromatic nitrations, 17 160-161 by-products of, 17 161 kinetics of, 17 162 Aromatic nitriles, 17 243 Aromatic nucleophilic displacement, polyimide synthesis via, 20 273 Aromatic phosphines, 19 60, 62 Aromatic poly(monosulfide ketone)s, 23 709 Aromatic poly(monosulfide)s, 23 706 Aromatic polyamide copolymers, laboratory synthesis of, 19 720 Aromatic polyamide fibers, 24 614 Aromatic polyamides, 10 210-212 19 713-738. See also Aliphatic polyamides (PA)... 

The reactions were carried out by using trans-chloro( 1-naphthyl)-bis(triphenylphosphine)nickel(II) (l, Ar = Ci0H7) complex as catalyst in the presence of various phosphorus ligands. We observed that aromatic phosphines in arylnickel(II) complexes 1 are easily replaced by aliphatic phosphines. In fact in the presence of alkylphosphines, such as P( C6Hn )3 and P(C4H9)3, cyanation did not occur. Moreover phosphites such as... 

In the synthesis of specially substituted methylene diphosphines, made from secondary phosphines and carbonyl derivatives (7), a carbenium ion adjacent to trivalent phosphorus as the transition state has been discussed. The transfer of this reaction principle to primary phosphines and suitable carbonyl compound revealed a further pathway to derivatives of dicoordinated phosphorus (8). Aromatic phosphines react with carboxylic acid amide acetals under elimination of alcohol giving dialkylamino-alkylidene phosphines (Scheme 5). A modification of the synthesis... 

The first two examples in Figure 1.20 illustrate that the structural formulas of alkyl and aromatic phosphine compounds may be derived by substituting organic groups for the H atoms in phosphine (PH3), the hydride of phosphorus, discussed as a toxic inorganic compound in Section 12.10. Methylphosphine is a colorless, reactive gas. Crystalline, solid triphenylphosphine has a low reactivity and moderate toxicity when inhaled or ingested. 

Which inorganic compound is regarded as the parent compound of alkyl and aromatic phosphines Give an example of each of these. 

Amino and functional aromatic phosphates, phosphonates, and phosphine oxides have also been used as reactive components to impart flame retardancy to cured epoxy resins. Phosphine oxides are particularly hydrolytically stable and several studies have been reported, for example, of the curing of epoxy resins with bis(aminophenyl) alkyl and aryl phosphine oxides65-67 (Structure 5.19). The relative performances of epoxies cured with aromatic diamine hardeners containing phosphine oxide, phosphinate, phosphonate, or phosphate units have recently been assessed.68 Aromatic phosphine oxides have been functionalized also with maleimide and hydroxyl groups for use as epoxy resin hardeners.69,70... 

Protected amino acids can be made without any racemization and electron-withdrawing groups such as esters promote excellent regioselectivity in favour of terminal attack. These three examples rely on in situ reduction of the palladium (II) acetate by tri o-tolyl)phosphine, a popular more steri-cally demanding aromatic phosphine. 

Secondary aromatic phosphines can be prepared from the more readily available tertiary phosphines by cleavage of an aromatic residue using sodium in liquid ammonia/... 

Secondary aromatic phosphines can be prepared from tertiary phosphines by cleavage with sodium in liquid ammonia, and the detailed preparation of diphenylphosphine by this method has been reported. Diphenylphosphine has also been prepared by the reaction of chlorodiphenylphosphine with alkali metals or with lithium tetrahydroaluminate. This phosphine has been also obtained from diphenyltrichlorophosphorane or tetraphenyldiphosphine-disulfide with lithium aluminum hydride. A faster and easier method of preparation, which gives equally high yields, consists in the cleavage of tri-phenylphosphine with lithium metal in tetrahydrofuran, followed by hydrolysis of lithium diphenylphosphide with water to generate the phosphine. ... 

Hydrolysis of alkyl-substituted phosphine oxides is generally difficult, heating with solid sodium or potassium hydroxide is needed in order to break the P—C bond. Hydrolysis of phosphonates and phos-phinates occurs with P—O cleavage in preference to P—C cleavage. Exceptions have been reported with several aromatic phosphine oxides containing p- and o-nitrobenzyl groups and other stabilized systems. Perfluorinated phosphine oxides can also be hydrolyzed to the phosphinic and phosphonic acids.2 ... 

A similar reaction has been carried out between the aromatic phosphine alcohol 90 and [RhCl(C8Hi4)3]2 in THE under a nitrogen atmosphere at room temperature affording the complex 91, as proved spectroscopically by H, H- P and P H NMR, IR, and FD-MS measurements (Equation 28) <1998JA6531>. 

By Replacement of Zerovalent Isocyanide Derivatives. This method was described for preparing the tris and tetrakis palladium (0) derivatives with tertiary aromatic phosphines and phosphites 129). It might be extended to nickel. 

The use of palladium and ruthenium as halogen-free carbonylation catalysts has been studied intensively by Shell. The catalysts were principally designed for the carbonylation of olefins in the presence of alcohols in order to yield carboxylic esters [26], but work also well for the synthesis of carboxylic acids or anhydrides. The latter are formed when the reaction is conducted in an acid as a solvent [27]. The palladium systems typically consist of palladium acetate, tertiary phosphines, and strong acids such as mineral acids or acids with weak or noncoordinating anions such as p-toluenesulfonic acid. Remarkable activities are achieved when aromatic phosphines that carry pyridines as substituents are... 

Catalysts Containing Sulibnated Aromatic Phosphines as Ligands... 

---