Sonolysis organometallics

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

The sonochemistry of non-carbonyl organometallics has not yet been well developed. Complexes which contain both CO and Cp undergo CO substitution upon sonolysis (189). In preliminary studies of the metal-... 

Amide hydrolysis was described in the case of the chromium complex shown in Eq. 27.84 It is noteworthy that no alteration of the organometallic moiety occurs. In addition to the relative stability of chromium compoimds under sonication, the low-energy irradiation conditions selectively allowed the biphasic hydrolysis to occur, without promoting the more energy-demanding metal group sonolysis. 

The formation of active catalysts and nanostructures requires technology capable of producing finely divided materials. In fact, sonolysis of organometallic precursors enables the preparation of catalysts, amorphous powders, and intercalation compounds. o These sonolytic reactions can be applied when the metal atom is bound to neutral ligands, requiring no reduction. 

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