Uranium Hydridoborates: Synthesis, Magnetism, and X-ray/Neutron Diffraction Structures

Abstract

While uranium hydridoborate complexes containing the [BH 4 ] - moiety have been well-known in the literature for many years, species with functionalized borate centers remained considerably rare. We were now able to prepare several uranium hydridoborates (1-4) with amino-substituted borate moieties with high selectivity by smooth reaction of [Cp∗ 2 UMe 2 ] (Cp∗ = C 5 Me 5) and [Cp′ 2 UMe 2 ] (Cp′ = 1,2,4-tBu 3 C 5 H 2) with the aminoborane H 2 BN(SiMe 3) 2. A combination of nuclear magnetic resonance spectroscopy, deuteration experiments, magnetic SQUID measurements, and X-ray/neutron diffraction studies was used to verify the anticipated molecular structures and oxidation states of 1-4 and helped to establish a linear tridentate coordination mode of the borate anions. (Chemical Equation Presented).