Phosphines trimethylphosphine

In the presence of air, trimethyl, triethyl, and tributylphosphine combust spontaneously. In the presence of pure oxygen, even though it was at a low temperature, triethylphosphine detonated. In the same conditions, triphenyl-phosphine does not seem to be dangerous. Trimethylphosphine can be stored safely in the air in the form of a complex with silver iodide. 

For this complex, molecular chemistry does not adequately model the surface reactivity and the latter is strongly influenced by the presence of surface hydroxyl groups [22]. The organometallic fragments immobilized on silica have been reacted with trimethylphosphine to afford different silica-supported phosphine complexes of rhodium. The course of the reaction depends strongly on the hydroxyl content of the silica surface [23] (Scheme 7.2). 

As with conformational energy differences, SYBYL and MMFF molecular mechanics show marked differences in performance for rotation/inversion barriers. MMFF provides a good account of singlebond rotation barriers. Except for hydrogen peroxide and hydrogen disulfide, all barriers are well within 1 kcal/mol of their respective experimental values. Inversion barriers are more problematic. While the inversion barrier in ammonia is close to the experimental value, barriers in trimethylamine and in aziridine are much too large, and inversion barriers in phosphine and (presumably) trimethylphosphine are smaller than their respective experimental quantities. Overall,... 

IJaul Thenard produced trimethylphosphine from methyl chloride and impure calcium phosphide at 180-300 °C in 1847.1 After the discovery of aliphatic amines, the relationship between amines and phosphines stimulated Hofmann, and then Cahours,2 to develop this area of chemistry Michaelis synthesized triphenylphosphine in 1885.3... 

Several phosphine substituted derivatives of 5 have been synthesized by reaction of trimethylphosphine with 5 in n-pentane (12). 

The tetrakis(trimethylphosphine) derivative Fe4C(CO)9(PMe3)4 has been characterized by H, 3 P, and, 3C NMR spectroscopy, and on the basis of the presence of two equally populated phosphine sites is assigned the symmetric structure, each iron atom bearing one phosphine ligand and two carbonyls (12). This was confirmed by X-ray diffraction (13). 

X-ray diffraction provides a structural analysis of the adduct obtained between acetone and triethylphosphine (155) in the presence of bromine. The process of obtaining 155 is an acid-catalysed process, while the adducts obtained in the presence of chlorotrimethylsilane may be ascribed to neutral attack of the nucleophile leading to the zwitterionic complex, as shown in Scheme 46. In Scheme 46 triethylphosphine may be substituted by trimethylphosphine. When triphenylphosphine or tributylphosphine were used, no reactions were observed, owing to the reduced nucleophilic power of the bulky phosphines and to the insolubility of the obtained adducts. 

The first disilene-group-4 metal complex, disilene-hafnium complex 240, is synthesized using a similar reaction to those shown in Eqs. (108) and (109) [Eq. (113)].153 The reaction of 240 with trimethylphosphine gives the phosphine adduct 241 [Eq. 

Gas phase proton affinities of phosphabenzene and arsabenzene have been determined by ion-cyclotron resonance techniques 94>. These confirm the qualitative solution phase data (see Fig. 5). Phosphabenzene (PA = 194.5 kcal/mol) has a proton affinity nearly 30 kcal/mol less than trimethylphosphine and only slightly greater than that of phosphine. Arsabenzene (PA = 188.0 kcal/mol) has a proton affinity 23 kcal/mol less than trimethylarsine. In the case of arsabenzene, protonation occurred on carbon rather than arsenic so the As-basidty may be even lower. By contrast, the proton affinity of pyridine (PA = 218 kcal/mol) is only slightly less than that of trimethylamine (PA = 222 kcal/mol) but considerably larger than ammonia (PA = 202 kcal/mol). 

The combustion of aryl and alkyl phosphines, such as trimethylphosphine, occurs as shown by the following example ... 

The rhodium-trimethylphosphine system is remarkable because it catalyzes the dimerization of aryl substituted acetylenes, yielding the scarce branched head-to-tail coupling product [12], The iridium species generated from [Ir(COD)Cl]2 and phosphine selectively yields linear ( ) or (Z) enynes from silylalkynes, depending on whether triaryl or tripropylphosphines, respectively, are used [16]. 

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