II , CpFe dppe CN

CpFe(dppe)Br is prepared by the literature procedure. The solvents (methanol, CH2CI2, hexane) as well as potassium cyanide are obtained commercially and used as received. 

Institut fiir Anorganische und Analytische Chemie der Universitat Freiburg, Albertstr. 21, D-79104 Freiburg, Germany. 

A 100-mL single-necked round-bottomed flask is charged with a solution of CpFe(dppe)Br (1.50 g, 2.6 mmol) in 50 mL of methanol. Potassium cyanide (0.68 g, 10.4 mmol) is added and the resulting solution stirred for 3 h at room temperature. The solvent is removed under reduced pressure and the resulting solid is extracted 2 times with 15 mL of dichloromethane. The yellow-brown solution is layered with 60 mL of hexane, and the mixture is kept at room temperature for 2 days. After filtration, washing with hexane, and drying in vacuo, 1.07 g (74%) of CpFe(dppe)CN is obtained as yellow brown crystals. 

All manipulations are performed under an atmosphere of dry nitrogen by using standard Schlenk and syringe techniques. The solvents toluene, benzene, and hexane are dried by reflux over the drying agent sodium and distilled prior to use. Sodium bis(trimethylsilyl)amide is prepared by the literature procedure. W(CO)e is obtained commercially and used without further purification. 

A filtered solution of sodium bis(trimethylsilyl) amide (5.8 g, 31.6 mmol) in 100 mL of toluene is placed in a pressure-equalized dropping funnel (200 mL). The mixture is added dropwise to a magnetically stirred suspension of W(CO)e (11.3 g, 32.1 mmol) in 100 mL of toluene, contained in a 500-mL Schlenk flask. The mixture is stirred for 5 days at room temperature. The precipitate is collected by filtration with a large-diameter D3 Schlenk sintered-glass funnel and washed first with 3 X 30 mL of benzene and then with 3 x 30 mL of hexane. The filtration and washing steps may take more than one day. To prevent the sintered-glass 

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