THERMAL DECOMPOSITION OF BIS(CYCLOPENTADIENYL)HAFNIUM COMPOUNDS AND THEIR DEUTERATED ANALOGUES

Article abstract of DOI:10.1016/S0022-328X(00)81951-8

Thermal decomposition ranges of Cp2HfR2 (R=Me, Ph) have been found by the DTA method.The thermal stability of hafnium derivatives greatly exceeds the stability of analogous titanium and zirconium compounds.Decomposition of Cp2HfR2 occurs by abstraction of ?-bonded groups which convert into RH.Hydrogen donors for the RH formation are both ?-cyclopentadienyl and ?-bonded groups.The initial ?-Cp2Hf structure rearranges to form the (η⁵-Cp)-(η⁵,η¹-C5H4)Hf fragment.These react with HCl to produce Cp2HfCl2.It has been established that hydrogen exchange between cyclopentadienyl rings and methyl groups occurs during the thermal decomposition of Cp2HfMe2.As a result of the exchange process on thermal decomposition of Cp2HfMe2-d₆, deuterium insertion into the cyclopentadienyl ring has been shown.The participation of solvent during the decomposition process of the hafnium derivatives has been studied.