Tuning the Oxidation State, Nuclearity, and Chemistry of Uranium Hydrides with Phenylsilane and Temperature: The Case of the Classic Uranium(III) Hydride Complex [(C5Me5)2U(μ-H)]2

This work demonstrates that the oxidation state and chemistry of uranium hydrides can be tuned with temperature and the stoichiometry of phenylsilane. The trivalent uranium hydride [(C5Me5)2U–H]x (5) was found to be comprised of an equilibrium mixture of U­(III) hydrides in solution at ambient temperature. A single U­(III) species can be selectively prepared by treating (C5Me5)2UMe2 (4) with 2 equiv of phenylsilane at 50 °C. The U­(III) system is a potent reducing agent and displayed chemistry distinct from the U­(IV) system [(C5Me5)2U­(H)­(μ-H)]2 (2), which was harnessed to prepare a variety of organometallic complexes, including (C5Me5)2U­(dmpe)­(H) (6), and the novel uranium­(IV) metallacyclopentadiene complex (C5Me5)2U­(C4Me4) (11).本研究证实，氢化铀的氧化态与化学行为可通过反应温度以及苯基硅烷（phenylsilane）的化学计量比进行精准调控。三价氢化铀配合物[(C5Me5)2U–H]ₓ（编号5）在室温溶液中以U(III)氢化物的平衡混合物形式存在。通过在50℃条件下将二(五甲基环戊二烯基)二甲基铀[(C5Me5)2UMe2，编号4]与2当量苯基硅烷反应，可选择性制备单一的U(III)物种。该U(III)体系是一种强效还原剂，其反应特性与[(C5Me5)2U(H)(μ-H)]₂（编号2）所代表的U(IV)体系存在显著差异；借此可制备多种有机金属配合物，包括[(C5Me5)2U(双(二甲基膦基)乙烷（dmpe）)(H)]（编号6）以及新型四价铀金属环戊二烯配合物[(C5Me5)2U(C4Me4)]（编号11）。