Photolysis of RuCp(benzene)+ in CH&N at 313 nm gives a quantitative yield of [RuCp(CH,CN),]: which is isolated as the PF6-salt. The quantum yield for this reaction is 0.4 f 0.04. The thermal substitution chemistry of this complex is remarkably rich. When the reaction conditions are varied (temperature and solvent), one, two, or three of the CH&N molecules can be selectively replaced. For example, with P(OCH3), as the incoming ligand, reaction of [RUC~(CH&N)~]PF~ with an excess of P(OCH,), in acetonitrile at room temperature gives a quantitative yield of [RUC~(CH&N)~(P(OCH,)~)]PF~. Further treatment of this monophosphite complex with an excess of P(OCH,), for several days at room temperature yields quantitatively [RuCp(CH3CN)(P(OCH3),),]PF6. Finally, refluxing this bisphosphite complex with an excess of P(OCH3)3 for several hours in dichloroethane yields [ R U C~( P ( O C H~)~)~] P F~. [CpRu(CH,CN),]+ also reacts with a variety of unsaturated hydrocarbons to yield compounds in which all three acetonitrile molecules have been replaced. Compounds synthesized by this method include: [CpRu(q6-hexamethylbenzene)]PF6, [CpRu(q6-[2.2]-p-cyclophane)]PF6, [CpRu(~f-p-dichlorobenzene)]PF~, and [CpRu(q6-cyclooctatetraene)]PFs.

The photolysis of ]+ (xyl = xylene) in acetonitrile solution at -40 °C produces a purple intermediate that we have characterized as [(j/-CsH5)Fe(CH3CN)3]+ by lH NMR, electronic spectroscopy, and chemical reaction studies. Room-temperature photolysis of [(7j-C5H5)Fe(i)-p-xyl)]+ in acetonitrile also generates this species, which rapidly yields ferrocene and Fe(II) as the final products. Mechanistic studies on this system suggest that ferrocene is generated when [(7/-C5H5)Fe(CH3CN)3]+ releases C5H5~, which subsequently replaces three CH3CN molecules on an unreacted [(??-C5H5)Fe(CH3CN)3]+ ion. This tris(acetonitrile) complex is a convenient starting material for the synthesis of substituted complexes of the form [(»?-C5H5)Fe(CH3CN)(L)2]+, [(j!-C5H5)Fe(CH3CN)(L)(L,)]+, [(7)-CsH5)Fe(L)(L')2]+, and [(»?-C5H5)Fe(L)(L/)(L,')]+, where L, L', and L" = isocyanides, phosphites, or phosphines. Room-temperature photolysis of 65 (1981). (4) A. N.

No abstract