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Uranium Metalla‐Allenes with Carbene Imido R 2 C=U IV =NR′ Units (R=Ph 2 PNSiMe 3 ; R′=CPh 3 ): Alkali‐Metal‐Mediated Push–Pull Effects with an Amido Auxiliary
Author(s) -
Lu Erli,
Tuna Floriana,
Lewis William,
Kaltsoyannis Nikolas,
Liddle Stephen T.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201602603
Subject(s) - alkali metal , allene , amide , carbene , chemistry , lithium (medication) , uranium , metal , lithium amide , crystallography , stereochemistry , medicinal chemistry , inorganic chemistry , physics , organic chemistry , nuclear physics , catalysis , medicine , enantioselective synthesis , endocrinology
We report uranium(IV)‐carbene‐imido‐amide metalla‐allene complexes [U(BIPM TMS )(NCPh 3 )(NHCPh 3 )(M)] (BIPM TMS =C(PPh 2 NSiMe 3 ) 2 ; M=Li or K) that can be described as R 2 C=U=NR′ push–pull metalla‐allene units, as organometallic counterparts of the well‐known push–pull organic allenes. The solid‐state structures reveal that the R 2 C=U=NR′ units adopt highly unusual cis ‐arrangements, which are also reproduced by gas‐phase theoretical studies conducted without the alkali metals to remove their potential structure‐directing roles. Computational studies confirm the double‐bond nature of the U=NR′ and U=CR 2 interactions, the latter increasingly attenuated by potassium then lithium when compared to the hypothetical alkali‐metal‐free anion. Combined experimental and theoretical data show that the push–pull effect induced by the alkali metal cations and amide auxiliary gives a fundamental and tunable structural influence over the C=U IV =N units.