Silyl‐Phosphino‐Carbene Complexes of Uranium(IV) |
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Authors: | Dr Erli Lu Josef T Boronski Dr Matthew Gregson Dr Ashley J Wooles Prof Stephen T Liddle |
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Institution: | School of Chemistry, The University of Manchester, Manchester, UK |
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Abstract: | Unprecedented silyl‐phosphino‐carbene complexes of uranium(IV) are presented, where before all covalent actinide–carbon double bonds were stabilised by phosphorus(V) substituents or restricted to matrix isolation experiments. Conversion of U(BIPMTMS)(Cl)(μ‐Cl)2Li(THF)2] ( 1 , BIPMTMS=C(PPh2NSiMe3)2) into U(BIPMTMS)(Cl){CH(Ph)(SiMe3)}] ( 2 ), and addition of Li{CH(SiMe3)(PPh2)}(THF)]/Me2NCH2CH2NMe2 (TMEDA) gave U{C(SiMe3)(PPh2)}(BIPMTMS)(μ‐Cl)Li(TMEDA)(μ‐TMEDA)0.5]2 ( 3 ) by α‐hydrogen abstraction. Addition of 2,2,2‐cryptand or two equivalents of 4‐N,N‐dimethylaminopyridine (DMAP) to 3 gave U{C(SiMe3)(PPh2)}(BIPMTMS)(Cl)]Li(2,2,2‐cryptand)] ( 4 ) or U{C(SiMe3)(PPh2)}(BIPMTMS)(DMAP)2] ( 5 ). The characterisation data for 3 – 5 suggest that whilst there is evidence for 3‐centre P?C?U π‐bonding character, the U=C double bond component is dominant in each case. These U=C bonds are the closest to a true uranium alkylidene yet outside of matrix isolation experiments. |
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Keywords: | alkylidenes carbenes metal– ligand multiple bonding phosphines uranium |
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