US EPA

3729505 

Journal Article 

Synthesis and CO2 Insertion Chemistry of Uranium(IV) Mixed-Sandwich Alkyl and Hydride Complexes 

Higgins, JA; Cloke, FGN; Roe, SM 

2013 

1 

Organometallics
ISSN: 0276-7333
EISSN: 1520-6041 

32 

19 

5244-5252 

10.1021/om400720m 

WOS:000326122600002 

A series of U(IV) mixed-sandwich alkyls of the form [U(COTTIPS2)Cp*R] (R = Me, CH2Ph, CH2TMS, CH(TMS)(2); COTTIPS2 = C8H6(SiiPr3-1,4)(2); Cp* = C5Me5; TMS = SiMe3) have been synthesized and structurally characterized, and their reactivity toward H-2 and CO2 has been investigated. investigated. The alkyls R = Me, CH2Ph, CH2TMS react at room temperature with a stoichiometric amount of CO2 to form kappa(2)-carboxylate complexes. Reaction of all four alkyls with H-2 yields a monomeric, terminal hydride complex, [U(COTTIPS2)Cp*H], which is unstable with respect to hydrogen loss and reacts with CO2 to give the kappa(2)-formate complex [U(COTTIPS2)Cp*(kappa(2)-O2CH)]. Additionally, a common decomposition product of the alkyls and hydride complex-activation of a Cp* methyl group to give a "tucked-in" alkyl has been isolated and structurally characterized and its insertion chemistry toward CO2 has been examined.