Preparation of (1,5-cyclooctadiene)chlororhodium (I) dimer; rhodium complex
Submitted May 10, 2007, published May 14, 2007
Rhodium trichloride hexahydrate (Precious Metals Online)
The synthesis is performed under nitrogen, however, all work up procedures are carried out in air. A mixture of RhCl3(H2O)6 (2.0 g, 6.3 mmol), deoxygenated ethanol-water (5:1, 20 mL) and 1,5-cyclooctadiene (3 mL) were heated at reflux under nitrogen for 24 h, during this time period the product precipitated as a yellow-orange solid. After the reflux time was complete, the mixture was cooled to room temperature and the product was collected by filtration on a pre-weighed glass frit. The product was washed with pentane and methanol-water (v/v, 1:5, ~50 mL). The resulting yellow-orange powder was dried in vacuo (10-3 mbar) for 24 h. Yield: 1.47 g, 2.98 mmol, 95%.
1H NMR (500 MHz, CDCl3) 1.75 (4 H, m, CH2), 2.52 (4H, m, CH2), 4.23 (4H, s, CH).
G. Giordano and R. H. Crabtree, Inorganic Syntheses, 1979, 19, 218.
J. Chatt and L.M. Venanzi, J. Chem. Soc., 1957, 4735.
Keywords: Rhodium, cyclooctadiene, chloride, hydrogenation, reduction, substitution, alkenes, inorganic compounds, organometallics