Seed John A, Vondung Lisa, Barton Franky, Wooles Ashley J, Lu Erli, Gregson Matthew, Adams Ralph W, Liddle Stephen T
Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Chemistry. 2022 Jul 1;28(37):e202200761. doi: 10.1002/chem.202200761. Epub 2022 May 23.
We report the synthesis and characterisation of a series of rare-earth mesoionic carbene complexes, [RE{N(SiMe ) } {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 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 energy barriers of 35 and 128 K, respectively. Complex 3Dy is, as expected, a poorly performing SMM, but conversely 3Er performs unexpectedly well.
我们报道了一系列稀土中离子卡宾配合物[RE{N(SiMe₃)₂}{CN(Me)C(Me)N(Me)CH}]（3RE，RE = Sc、Ce、Pr、Sm、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu）的合成与表征，极大地扩展了f族中离子卡宾配合物有限的库。这些配合物是通过用N - 杂环烯烃（NHO）处理母体RE - 三酰胺制备的，其中NHO主链质子经历形式上的1,4 - 质子迁移至NHO - 亚甲基。对于所有RE(III)金属，正如预期的那样，量子化学计算表明金属 - 卡宾键合仅具有σ成分，这与先前报道的铀(III)同系物不同，在该同系物中5f金属与中离子卡宾（MIC）存在弱π - 反馈键。所有配合物都通过静态变温磁性测量进行了表征，动态磁性测量表明3Dy和3Er是场诱导单分子磁体（SMM），其U能量势垒分别为35 K和128 K。正如预期的那样，配合物3Dy是性能较差的SMM，但相反，3Er的性能出人意料地好。
