Abstract
We report the synthesis and characterisation of a series of rare-earth mesoionic carbene complexes, [RE{N(SiMe 3) 2} 3{CN(Me)C(Me)N(Me)CH}] (3RE, RE=Sc, Ce, Pr, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), greatly expanding the limited library of f-block mesoionic carbene complexes. These complexes were prepared by treatment of the parent RE-triamides with an N-heterocyclic olefin (NHO), where an NHO backbone proton undergoes a formal 1,4-proton migration to the NHO-methylene group. For all RE(III) metals, as expected, quantum chemical calculations suggest only a σ-component to the metal−carbene bonding, in contrast to a previously reported uranium(III) congener where the 5f 3 metal engages in a weak π-back-bond to the MIC. All complexes were characterised by static variable-temperature magnetic measurements, and dynamic magnetic measurements reveal that 3Dy and 3Er are field-induced single-molecule magnets (SMMs), with U eff energy barriers of 35 and 128 K, respectively. Complex 3Dy is, as expected, a poorly performing SMM, but conversely 3Er performs unexpectedly well.
Original language | English |
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Article number | e202200761 |
Journal | Chemistry – A European Journal |
Volume | 28 |
Issue number | 37 |
Early online date | 26 Apr 2022 |
DOIs | |
Publication status | Published - 26 Apr 2022 |
Keywords
- mesoionic carbenes
- density functional theory
- rare earth elements
- N-heterocyclic olefins
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EPSRC National Research Facility for Electron Paramagnetic Resonance
Collison, D. (Academic lead), Mcinnes, E. (Academic lead), Tuna, F. (Academic lead), Bowen, A. (Academic lead), Shanmugam, M. (Senior Technical Specialist), Brookfield, A. (Technical Specialist), Fleming, E. (Other) & Cliff, M. (Platform Lead)
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