Intrinsic reactivity of a uranium metallacyclopropene toward unsaturated organic molecules

Lei Zhang; Bo Fang; Guohua Hou; Lin Ai; Wanjian Ding; Marc D Walter; Guofu Zi

doi:10.1039/c6dt03005j

Intrinsic reactivity of a uranium metallacyclopropene toward unsaturated organic molecules

Dalton Trans. 2016 Oct 18;45(41):16441-16452. doi: 10.1039/c6dt03005j.

Authors

Lei Zhang¹, Bo Fang¹, Guohua Hou¹, Lin Ai¹, Wanjian Ding¹, Marc D Walter², Guofu Zi¹

Affiliations

¹ Department of Chemistry, Beijing Normal University, Beijing 100875, China. dingwanjian@bnu.edu.cn gzi@bnu.edu.cn.
² Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany. mwalter@tu-bs.de.

PMID: 27711790
DOI: 10.1039/c6dt03005j

Abstract

The uranium metallacyclopropene (η⁵-C₅Me₅)₂U[η²-C₂(SiMe₃)₂] (1) reacts with various small unsaturated organic molecules. For example, replacement of bis(trimethylsilyl)acetylene occurs when complex 1 is exposed to alkynes, conjugated alkenes, nitriles and quinones. Reaction of 1 with internal phenyl(alkyl)acetylene PhC[triple bond, length as m-dash]CMe selectively yields the C_s symmetric uranium metallacyclopentadiene (η⁵-C₅Me₅)₂U[η²-C(Ph)[double bond, length as m-dash]C(Me)-C(Ph)[double bond, length as m-dash]C(Me)] (6) after the loss of bis(trimethylsilyl)acetylene, while treatment of 1 with phenyl(silyl)acetylenes (PhC[triple bond, length as m-dash]CR, R = SiHMe₂, SiMe₃) gives the corresponding C_2v symmetric isomers (η⁵-C₅Me₅)₂U[η²-C(R)[double bond, length as m-dash]C(Ph)-C(Ph)[double bond, length as m-dash]C(R)] (R = SiHMe₂ (7), SiMe₃ (8)). Furthermore, while no deprotonation occurs between complex 1 and pyridine derivatives, cyclohexanone can be inserted into the uranium metallacyclopropene moiety of 1 to yield the five-membered, heterocyclic complex (η⁵-C₅Me₅)₂U[OC(CH₂)₅(C₂(SiMe₃)₂)] (14) in quantitative conversion. Density functional theory (DFT) studies have been performed to complement the experimental studies.