Solution structure and behavior of dimeric uranium(III) metallocene halides
- Lawrence Berkeley Lab., CA (United States)
The variable-temperature {sup 1}H NMR behavior of the uranium(III) dimers [Cp{double_prime}{sub 2}UX]{sub 2} and [Cp{sup {double_dagger}}{sub 2}UX]{sub 2}, where X is F, Cl, Br, or I, Cp{double_prime} is 1,3-(Me{sub 3}Si){sub 2}C{sub 5}H{sub 3}, and Cp{sup {double_dagger}} is 1,3-(Me{sub 3}C){sub 2}C{sub 5}H{sub 3}, has been examined. At low temperature, the number of inequivalent CMe{sub 3} or SiMe{sub 3} groups implies that the solution structure is the same as the solid-state structure in all of these complexes. The barriers to ring rotation in the Cp{double_prime} series are strongly dependent upon the U-X distance, but all of the barriers to ring rotation in the Cp{sup {double_dagger}} series are the same. The trends in ring rotation barriers are explained by the different conformations of the Cp ligands in the dimers. In addition to the homo-halide dimers, the variable-temperature NMR behavior of the hetero-halide dimers Cp{prime}{sub 4}({mu}-X)({mu}-Y), where Cp{prime} is Cp{double_prime} or Cp{sup {double_dagger}} and X and Y are halides where X {ne} Y, was examined. Above room temperature, the halide atoms exchange sites rapidly on the NMR time scale.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 343701
- Journal Information:
- Organometallics, Journal Name: Organometallics Journal Issue: 7 Vol. 18; ISSN ORGND7; ISSN 0276-7333
- Country of Publication:
- United States
- Language:
- English
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