Bis[1,3-bis(diphenylphosphino)propane]rhodium Tetrafluoroborate

The product Bis[1,3-bis(diphenylphosphino)propane]rhodium Tetrafluoroborate is recrystallized from a solvent mixture of CH2Cl2 and Et2O by a standard layering technique. The orange-yellow flakes of [Rh(dppp)2]BF4 are dissolved in a minimum amount of CH2Cl2 in a Schlenk tube equipped with a rubber septum. A volume of Et2O (ca. 3 times the CH2Cl2 volume) is carefully layered on top with use of a syringe or cannular tube. The solvents are allowed to slowly diffuse, and large red crystals are isolated. The red crystals are washed with Et2O and dried under vacuum.

All manipulations are carried out under a nitrogen atmosphere using standard Schlenk techniques. Rh2Cl2(1,5-cyclooctadiene)2 (400 mg, 1.63 mmol) is dissolved in 50 mL of degassed acetone to which Silver(I) Tetrafluoroborate (337 mg, 1.73 mmol) is added to precipitate AgCl. The mixture is stirred for 1 h and filtered. The filtrate is added to an acetone solution of dppp (1,3-Bis(diphenylphosphino)propane) (1.58 g, 3.84 mmol). The acetone is partially evaporated under vacuum leaving a precipitate of orange-yellow flakes of [Rh(dppp)2]BF4 (Bis[1,3-bis(diphenylphosphino)propane]rhodium Tetrafluoroborate) in high yield.

1. Doughty, D. H.; Anderson, M. P.; Casalnuovo, A. L.; McGuiggan, M. F.; Tso, C. C.; Wang, H. H.; Pignolet, L. H. Adv. Chem. Ser. 1982, 196, 65.
2. Doughty, D. H.; Pignolet, L. H. JACS 1978, 100, 7083.
3. Doughty, D. H.; McGuiggan, M. F., Wang, H. H.; Pignolet, L. H.; Fundam. Res. Homogeneous Catal. 1979, 3, 909.
4. Preparation adapted from Slack, D. A.; Baird, M. C. JOM 1977, 142, C69.