A linear cobalt(II) complex with maximal orbital angular momentum from a non-Aufbau ground state
A linear cobalt(II) complex with maximal orbital angular momentum from a non-Aufbau ground state
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DOI：
10.1126/science.aat7319
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发表时间：
2018-12-21
期刊：
影响因子：
56.9
通讯作者：
Long, Jeffrey R.
中科院分区：
文献类型：
--
作者：
Bunting, Philip C.;Atanasov, Milian;Long, Jeffrey R.
轨道角动量是磁各向异性的先决条件，尽管在过渡金属络合物中，它通常被配体场淬灭。通过降低一对烷基配体中碳给体原子的碱性，我们合成了一个钴（II）二烷基配合物Co（C（SiMe（2）ONaph）（3））（2）（其中Me是甲基，Naph是萘基），其中配体场足够弱，电子间排斥和自旋轨道耦合在决定电子基态中起主导作用.非Aufbau（d（x2-y2，）d（xy））（3）（d（xz），d（yz），）（3）（d（z2））（1）电子组态的归属得到直流磁化率数据、实验电荷密度图和从头计算的支持。可变场远红外光谱和交流磁化率测量进一步揭示了缓慢的磁弛豫通过450波数磁激发态。
Orbital angular momentum is a prerequisite for magnetic anisotropy, although in transition metal complexes it is typically quenched by the ligand field. By reducing the basicity of the carbon donor atoms in a pair of alkyl ligands, we synthesized a cobalt(II) dialkyl complex, Co(C(SiMe(2)ONaph)(3))(2) (where Me is methyl and Naph is a naphthyl group), wherein the ligand field is sufficiently weak that interelectron repulsion and spin-orbit coupling play a dominant role in determining the electronic ground state. Assignment of a non-Aufbau (d(x2-y2,)d(xy))(3)(d(xz), d(yz),)(3)(d(z2))(1) electron configuration is supported by dc magnetic susceptibility data, experimental charge density maps, and ab initio calculations. Variable-field far-infrared spectroscopy and ac magnetic susceptibility measurements further reveal slow magnetic relaxation via a 450-wave number magnetic excited state.