Bis Triphenylphosphoranylidene Ammonium Tetracarbonylcyanoferrate O , Fe CO 4 CN

The white microcrystalline [PPN][Fe(CO)4(CN)] is moderately air sensitive and should be handled under an inert atmosphere. Complex PPN[Fe(CO)4(CN)] is readily soluble in THF, acetonitrile, and dichloromethane. 

In a 50-mL Schlenk flask is prepared a stirred solution of PPN[Fe(CO)4(CN)] (0.5 mmol, 0.365 g) in THF (8 mL) sealed with a rubber septum. This solution is treated dropwise with 120, u L of a 5 M solution of BrCN (0.6 mmol) in MeCN. The oxidative reaction is immediately indicated by evolution of CO gas. At this time, a needle is quickly inserted into the rubber septum to release the CO gas. After 30 min of stirring at room temperature, the reaction mixture is filtered through Celite and hexane (25 mL) is added to precipitate the light yellow solid. Recrystallization by dissolution in THF (10 mL) followed by the addition of diethyl ether (50 mL) gives the light yellow solid [PPN][FeBr(CO)3(CN)2]. Yield 0.277 g (68%). 

The light yellow microcrystalline [PPN][FeBr(CO)3(CN)2] is moderately air sensitive and reacts slowly with air to yield an impure light yellow solid. Complex [PPN][FeBr(CO)3(CN)2] is readily soluble in organic solvents, such as tetrahy-drofuran, acetonitrile, and dichloromethane. Although THF solution of complex [PPN][FeBr(CO)3(CN)2] is moderately air sensitive at room temperature, it should be handled under an inert atmosphere. 

Fontecilla-Camps, Structure (London) 7, 557 (1999). (c) R. Happe, W. Rosenboom, A. J. Pierik, 

Rousset, Y. Montet, B. Guigliarelli, N. Forget, M. Asso, P. Bertrand, J. C. Fontecilla-Camps, and E. C. Hatchikian, Proc. Natl. Acad. Sci. USA. 95, 11625 (1998). 

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