TY - JOUR
T1 - A Series of Rare‐Earth Mesoionic Carbene Complexes
AU - Seed, John A.
AU - Vondung, Lisa
AU - Barton, Franky
AU - Wooles, Ashley J.
AU - Lu, Erli
AU - Gregson, Matthew
AU - Liddle, Stephen
AU - Adams, Ralph
PY - 2022/4/26
Y1 - 2022/4/26
N2 - 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 characterized 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.
AB - 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 characterized 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.
U2 - 10.1002/chem.202200761
DO - 10.1002/chem.202200761
M3 - Article
JO - Chemistry: A European Journal
JF - Chemistry: A European Journal
SN - 0947-6539
ER -