Tetrabutylammonium Tetraoxorhenate VII

Sodium perrhenate (2.0 g, 7.3 mmol) is dissolved in demineralized water (100 mL) in a 250-mL conical flask. The solution is stirred and heated to 60°C then added to a warm (60°C) solution of tetrabutylammonium chloride (2.6 g, 9.3 mmol) in demineralized water (100 mL) in a 250-mL conical flask. The solution is left to stir for 30 min at room temperature. The white solid which forms is collected on a No. 3 sintered-glass filter tube, by filtration, and washed with distilled water (4 x 20 mL) and diethyl ether (4 x 30 mL) and dried in vacuo for 5 h at 56°C (boiling acetone) (yield 2.86 g, 79%). 

Infrared (NaCl disc, Nujol mull) v(Re = 0) 905 cm-1, v(CH) 722 cm 1. Soluble in chloroform and dichloromethane. 

---