He Mian, Guo Fu-Sheng, Tang Jinkui, Mansikkamäki Akseli, Layfield Richard A
Department of Chemistry , School of Life Sciences , University of Sussex , Brighton , BN1 9QR , UK . Email:
Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Renmin Street 5626 , 130022 Changchun , China . Email:
Chem Sci. 2020 May 18;11(22):5745-5752. doi: 10.1039/d0sc02033h. eCollection 2020 Jun 14.
The dinucleating fulvalenyl ligand [1,1',3,3'-(C BuH)] (Fv) was used to synthesize the dimetallic dysprosocenium cation [{Dy(η-Cp*)}(μ-BH)(η:η-Fv)] () as the salt of [B(CF)] (Cp* = CMe). Compound [][B(CF)] was obtained using a method in which the double half-sandwich complex [{Dy(BH)(THF)}(Fv)] () was reacted with KCp* to give the double metallocene [{Dy(Cp*)(μ-BH)}(Fv)] (), followed by removal of a bridging borohydride ligand upon addition of [(EtSi)(μ-H)][B(CF)]. The dimetallic fulvalenyl complexes give rise to single-molecule magnet (SMM) behaviour in zero applied field, with the effective energy barriers of 154(15) cm, 252(4) cm and 384(18) cm, respectively, revealing a significant improvement in performance across the series. The magnetic properties are interpreted with the aid of calculations, which show substantial increases in the axiality of the crystal field from to to as a consequence of the increasingly dominant role of the Fv and Cp* ligands, with the barrier height and hysteresis properties being attenuated by the equatorial borohydride ligands. The experimental and theoretical results described in this study furnish a blueprint for the design and synthesis of poly-cationic dysprosocenium SMMs with properties that may surpass those of benchmark systems.
双核富瓦烯基配体[1,1',3,3'-(C BuH)] (Fv) 用于合成二金属镝正离子[{Dy(η-Cp*)}(μ-BH)(η:η-Fv)] ()，作为[B(CF)]的盐（Cp* = CMe）。化合物[][B(CF)]是通过以下方法获得的：双半夹心配合物[{Dy(BH)(THF)}(Fv)] () 与KCp反应生成双茂金属[{Dy(Cp)(μ-BH)}(Fv)] ()，然后在加入[(EtSi)(μ-H)][B(CF)]后去除桥连硼氢化物配体。二金属富瓦烯基配合物在零外场下呈现单分子磁体（SMM）行为，有效能垒分别为154(15) cm、252(4) cm和384(18) cm，表明该系列性能有显著提升。借助计算对磁性能进行了解释，计算结果表明，由于Fv和Cp*配体的主导作用日益增强，晶体场的轴向性从 到 再到 大幅增加，而赤道硼氢化物配体使能垒高度和磁滞性能减弱。本研究中描述的实验和理论结果为设计和合成性能可能超越基准体系的聚阳离子镝正离子单分子磁体提供了蓝图。
