Cyclooctadiene pyridine tricyclohexylphosphine iridium I Hexafluorophosphate

In a 100-mL Schlenk tube equipped with a stirring bar, 0.30 g (0.5 mmol) of (T] -l,5-cyclooctadiene)bis(pyridine)iridium(I) hexafluorophosphate is dissolved in 20 mL of deoxygenated methanol under nitrogen. To this solution is added 0.17 g (0.6 mmol) of tricyclohexylphosphine (tcyp) [Strem Chemical]. The orange solution is stirred for 15 min at room temperature, during which time the product begins to crystallize from the solution. The mixture must not be heated. The methanol is removed under reduced pressure at room temperature until about 5 mL remains. Diethyl ether (10 mL) is added, and the reaction mixture is cooled in an ice bath for 30 min. The orange crystalline product is isolated by filtration, washed three times with 5-mL portions of diethyl ether, and dried under vacuum. Yield 0.39 g (97%). 

This complex is air-stable both in the solid state and in solution. It is soluble in CH2CI2, CHCI3, and Mc2CO but insoluble in alcohols, water, benzene, diethyl ether, and hexane. The compound [Ir(cod)(tcyp)(py)][PFJ can be recrystalliz d from dichloromethane/diethyl ether and identified by its H NMR spectrum. The cyclooctadiene vinyl protons appear at 8 4.02 in the NMR. Other resonances are observed for cyclohexylphosphine (8 0.8-2.5 complex), and for the asyl groups(8 7.6-7.9 and 8 8.7-8.8 complex) (CDCI3, 25°). The details for the use of the complex in hydrogenation are described elsewhere.  

Inorganic Syntheses, Volume 24 Edited by Jeaa ne M. Slireeve 1986 by Inorganic Syntheses, Inc. 

We thank Johnson Matthey Co. for a loan of iridium, and the Petroleum Research Fund, administered by the American Chemical Society, for funding. 

Crabtree, J. M. Quirk, H. Felkin, and T. Fillebeen-Kahn, Synth. React. Inorg. Met-Org. Chem., 12, 407 (1982). 

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Related Reagents. Bis(bicyclo[2.2.1]hepta-2,5-diene)rho-dium Perchlorate [l,4-Bis(diphenylphosphino)butane](norbora-diene)rhodium Tetrafluroborate Catecholborane (1,5-Cycloocta-diene)[ 1,4-Bis(diphenylphosphino)butane]iridium(I) Tetrafluoro-borate (1,5-Cyclooctadiene)(tricyclohexylphosphine)(pyridine) iridium(I) Hexafluorophosphate Octacarbonyldicobalt Palladium (II) Chloride Tetrakis(triphenylphosphine)palladium(0) 2-Amino-3-picoline Benzylamine. 

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