THF Activation from the Synthesis of Reactive Uranium(III)-Pnictogen Bonds

Herein, we report the synthesis of bis(hydrotris(pyrazolyl)borate) (Tp*) uranium(III) complexes that have activated and ring-opened a tetrahydrofuran (THF) molecule. Using Tp*2UBn (1-Bn) and secondary pnictines, a family of compounds was synthesized, Tp*2UO(CH2)4PPh2 (1-PPh2), Tp*2UO(CH2)4PMes2 (1-PMes2) and Tp*2UO(CH2)4AsMes2 (1-AsMes2). These complexes were characterized by 1H NMR spectroscopy, single crystal X-ray diffraction, electronic absorption spectroscopy, and IR spectroscopy. The occurrence of the THF ring opening demonstrates the preference of U(III) for the electronegative oxygen atom as opposed to the softer pnictogen elements.