Acetonitrile, complexes with metal halides

The donor properties of N3P3CI6 appear to be too weak to allow complex formation with metal halides, but it has been reported that complex formation between N3P3Cl5 NHBu" and Cu" or Co" chlorides in acetonitrile solutions can be detected by u.v. spectroscopy. Attempts to isolate the complexes were unsuccessful. 

Metal dithiophosphinato complexes are usually prepared by metathesis of metal halides with alkali metal or ammonium dithiophoshinates, but can also be conveniently prepared by reactions of /i .v(thiophosphinyl)disul fanes, R2(S)PSSP(S)R2, with metal species.87 The electrochemical oxidation of metals in acetonitrile solution, in the presence of diphenylphosphine and sulfur affords M(S2PPh2)2 (M = Co, Zn, Cd),88 but this is not a preparative method. 

Uniformly, within this group of cations, perchlorate ion accompanying the transition-element cation is replaced by nitrate (7,31), thiocyanate (7,52), or halide (7,6). Nitrate is probably replaced by thiocyanate, but a secondary change takes place in many systems, which makes direct comparison difficult (see below). If one then makes the further reasonable assumption that solvent interference can be used as an inverse measure of tendency to bind to the central metal cations, thiocyanate, whose competition with alcohol is less efficient (52) than that of chloride (6), should be somewhat replaceable with chloride. Comparisons between chloride and thiocyanate in acetonitrile show also that the formation of a complex with a given anion/cation ratio takes place much more readily with chloride than with thiocyanate (55, 34). By the same criterion, from experiments in alcoholic solution (55), bromide should replace chloride, and an extrapolation of the behavior to iodide seems reasonable. 

Organic nitriles, in particular acetonitrile, form stable electron-donor-acceptor (EDA) complexes with a number of Lewis acids such as BX3(X = Cl, Br, 1), SnC, AICI3, and with many transition metal halides, the nitrile group acting as the electron donor ... 

Diorgano ditellurium compounds react with transition metal salts and carbonyl complexes to form coordination compounds (Table 5, p. 283). Complexes with the following transition metals have been reported Ti, Cr, Mo, W, Mn, Re, Fe, Ir, Ni, Pd, Pt, Cu, Ag, Cd, Hg, Yb, and U. In many of these complexes, the organyltelluro group bridges the metal atoms in binuclear complexes. The Te —Te bond seems to remain intact upon complexation to mercury halides, rhenium carbonyls, and uranium pentachloride. For details on tellurolatO bridged complexes see p. 212. Complexes with SnCl are also known. Diphenyl ditellurium and bis[4-ethoxyphenyl] ditellurium formed charge-transfer complexes when equimolar amounts of the ditellurium compound and tetracyano-p-quinodime-thane were refluxed in acetonitrile. ... 

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