The Enhancement of Intercalation Reactions by Ultrasound

Ultrasonic irradiation increases the rates of intercalation (by as much as 200-fold) of organic and organometallic compounds into various layered inorganic oxide and sulphide host solids. The intercalation of organic or inorganic molecules into layered inorganic solid hosts is slow. Syntheses are often lengthy (weeks) and require elevated temperatures.1 In studying the synthesis and properties of intercalation com-pounds with organometallic guest molecules, we have found that the use of ultrasound significantly enhances the rates of intercalation reactions, as described herein. In a typical experiment, a 50 cm3 thermostatted glass vessel containing 0.5-1.0 g of the host solid and 15 cm3 of a toluene solution of the guest molecule in a 2: 1 molar excess under an N2 atmosphere was ultrasonically irradiated by direct immer-sion of a Ti horn with an acoustic intensity of ca. 20 Wkm3 (Heat Systems-Ultrasonics W375 Sonicator), as described in detail elsewhere.2 We have examined the effect of ultrasoun