Beyond the Tris-Cp Complexes

A cationic bis(pentamethylcyclopentadienyl)uranium(III) complex has been reported by Ephritikhine and coworkers [149]. The complex [(ri -C5Me5)2U(THF)2] [BPh4] is generated by the protonation of the complex (Ti5-C5Me5)2U[N(SiMe3)2] with [NH4][BPh4]. 

Cendrowski-Guillaume et al. reported the synthesis of a mixed cyclopen-tadienyl/cyclooctatetraenyl complex [U(COT)(Cp )(HMPA)] (where COT = q-CsHs, HMPA = OP(NMe2)3) [150] by the treatment of [U(COT)(HMPA)3] [BPh4] with KCp. The complex [U(COT)(Cp )(HMPA)] was characterized crystallographically and was found to adopt trigonal configuration as shown 

The complex [U(C5H4-f-Bu)l2(py)3] was characterized by X-ray crystallography and the average U-C, U-I and U-N bond distances were found to be 2.80(5), 3.17(2), and 2.66(5) A, respectively. On investigating the affinity of cyclopentadienyl ligand, (CsH4-f-Bu), towards Ln(III) (Ln = La, Ce, Nd) and U(III), it was reported that the U(III) center is relatively more prone to coordinate the cyclopentadienyl Hgand [151]. 

Investigating the mix Hgand complexes, Summerscales et aL discovered that the U(lll) COT /Cp mixed sandwich complex [U(T)-C8H6 Si-i-Pr3-l,4 2) (Cp )(THF)] induces efficient cyclotrimerization of CO to give [Ulti-CgHe Si-z-Pr3-l,4 2)(Cp )]2(pL-Ti h -C303) [152]. 

To carry out a comparative study of structural features, magnetic properties, and reactivities of the lanthanides(III) and actinides(lll), Mehdoui et al. [154] reported the synthesis of complexes of the type [(Cp )2Ml(bipy)j 

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