biostudies-literatureTsoureas NEuropean Research CouncilUniversity Of SussexEngineering and Physical Sciences Research Council4624-4632https://www.ebi.ac.uk/biostudies/studies/S-EPMC6013772biostudies-literatureUnknown7(7)The synthesis and molecular structures of a U(v) neutral terminal oxo complex and a U(v) sodium uranium nitride contact ion pair are described. The synthesis of the former is achieved by the use of ^<i>t</i> BuNCO as a mild oxygen transfer reagent, whilst that of the latter is <i>via</i> the reduction of NaN₃. Both mono-uranium complexes are stabilised by the presence of bulky silyl substituents on the ligand framework that facilitate a 2e^- oxidation of a single U(iii) centre. In contrast, when steric hindrance around the metal centre is reduced by the use of less bulky silyl groups, the products are di-uranium, U(iv) bridging oxo and (anionic) nitride complexes, resulting from 1e^- oxidations of two U(iii) centres. SQUID magnetometry supports the formal oxidation states of the reported complexes. Electrochemical studies show that the U(v) terminal oxo complex can be reduced and the [U(iv)O]^- anion was accessed <i>via</i> reduction with K/Hg, and structurally characterised. Both the nitride complexes display complex electrochemical behaviour but each exhibits a quasi-reversible oxidation at <i>ca.</i> -1.6 V <i>vs.</i> Fc^+/0.Chemical scienceSteric control of redox events in organo-uranium chemistry: synthesis and characterisation of U(v) oxo and nitrido complexes.PMC6013772Project 247390247390EP/M023885/1Tsoureas NKilpatrick AFRCloke FGNInman CJfalseSteric control of redox events in organo-uranium chemistry: synthesis and characterisation of U(v) oxo and nitrido complexes.The synthesis and molecular structures of a U(v) neutral terminal oxo complex and a U(v) sodium uranium nitride contact ion pair are described. The synthesis of the former is achieved by the use of ^<i>t</i> BuNCO as a mild oxygen transfer reagent, whilst that of the latter is <i>via</i> the reduction of NaN₃. Both mono-uranium complexes are stabilised by the presence of bulky silyl substituents on the ligand framework that facilitate a 2e^- oxidation of a single U(iii) centre. In contrast, when steric hindrance around the metal centre is reduced by the use of less bulky silyl groups, the products are di-uranium, U(iv) bridging oxo and (anionic) nitride complexes, resulting from 1e^- oxidations of two U(iii) centres. SQUID magnetometry supports the formal oxidation states of the reported complexes. Electrochemical studies show that the U(v) terminal oxo complex can be reduced and the [U(iv)O]^- anion was accessed <i>via</i> reduction with K/Hg, and structurally characterised. Both the nitride complexes display complex electrochemical behaviour but each exhibits a quasi-reversible oxidation at <i>ca.</i> -1.6 V <i>vs.</i> Fc^+/0.2016-01-01T00:00:00Z2016 Jul2026-06-04T12:40:18.551Z2026-05-10T03:10:40.26ZS-EPMC60137723015511010.1039/c6sc00632a