Preparation of Dimethylphenylphosphine

Dimethylphenylphosphine is a ligand commonly used to prepare a large range of transition metal-organophosphorus complexes. This basic phosphine is easy to handle and presents a small cone angle.1,2 It is usually prepared in 40-50% yield by reaction of a solution of methylmagnesium halide with phenylphosphonous dichloride followed by hydrolysis with an excess of saturated aqueous ammonium chloride solution.3 4 In the present preparation the yield has been greatly increased (to 85%). 

A 2-L three-necked flask is equipped with a condenser, a mechanical stirrer, and a pressure-equalized dropping funnel. The vessel is flushed with nitrogen and 

Dimethylphenylphosphine is kept under nitrogen to avoid atmospheric oxidation. The purity of the phosphine can be checked by H-NMR. A concentrated solution (60% v v) of phosphine in CDC13, with Me4Si as internal standard, shows two sets of peaks, a complex multiplet at 6 = 7.0-7.5 (i = 5H) and a doublet centered at 6 = 1.2 (/= 6H and /P H = 1.9 Hz). The 31P-NMR ( H decoupled) shows a singlet at -45.89 ppm in CDC13 (25% v v) (85% H3P04 as external reference). Additional properties are d 6 0.9670s, nb9-s 1.5673.6 The IR and UV spectra can be found in references 7 and 8. 

Yakovleva, E. N. Tsvetkov, D. I. Lobanov, M. I. Kabachnik, and A. I. Shatensh-tein, Dokl. Akad. Nauk. SSSR., 170, 1103-6 (1966) Chemical Abstracts, 66, 37038g (1967). 

ELECTROCHEMICAL SYNTHESIS OF SALTS OF HEXAHALODIGALLATE(II) AND TETRAHALOGALLATE(ID) ANIONS 

The trithioite ester is stable in air but decomposes above 100°. It is stable towards water and acids but is rapidly decomposed by alkali. Oxidation with 3% hydrogen peroxide in acetic acid gives 5,5,5, -tributyl phosphorotrithioate (yield 58%, bp 162-164°/ torr. (lit. bp 166.5°/1 torr)). 

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