Synthesis of [(HIPTNCH₂CH₂)₃N]V Compounds (HIPT = 3,5-(2,4,6-<i>i</i>-Pr₃C₆H₂)₂C₆H₃) and an Evaluation of Vanadium for the Reduction of Dinitrogen to Ammonia

Abstract

Green [HIPTN3N]V(THF) ([HIPTN3N]3- = [(HIPTNCH2CH2)3N]3-, where HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C6H3) can be prepared in a 70-80% yield via the addition of H3[HIPTN3N] to VCl3(THF)3 in THF, followed by the addition of LiN(SiMe3)2. From [HIPTN3N]V(THF), the following have been prepared: {[HIPTN3N]VN2}K, [HIPTN3N]V(NH3), [HIPTN3N]V=NH, [HIPTN3N]V=NSiMe3, [HIPTN3N]V=O, [HIPTN3N]V=S, and [HIPTN3N]V(CO). No ammonia is formed from dinitrogen using {[HIPTN3N]VN2}K, [HIPTN3N]V=NH, or [HIPTN3N]V(NH3) as the initial species under conditions that were successful in the analogous [HIPTN3N]Mo system. X-ray structural studies are reported for [HIPTN3N]V(THF) and [HIPTN3N]V(NH3).