Shao Dong, Zhang Shao-Liang, Shi Le, Zhang Yi-Quan, Wang Xin-Yi
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, China.
Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University , Nanjing 210023, China.
Inorg Chem. 2016 Nov 7;55(21):10859-10869. doi: 10.1021/acs.inorgchem.6b00854. Epub 2016 Oct 7.
We herein reported the synthetic, structural, computational, and magnetic studies of four air-stable heptacoordinated mononuclear cobalt(II) complexes, namely, [Co(tdmmb)(HO)][BF] (1), [Co(tdmmb)(CN)]·2HO (2), [Co(tdmmb)(NCS)] (3), and [Co(tdmmb)(SPh)] (4) (tdmmb = 1,3,10,12-tetramethyl-1,2,11,12-tetraaza[3pyridino3-1,10-phenanthrolinophane-2,10-diene; SPh = thiophenol anion). Constrained by the rigid pentadentate macrocyclic ligand tdmmb, the Co centers in all of these complexes are in the heptacoordinated pentagonal-bipyramidal geometry. While the equatorial environments of these complexes remain very similar to each other, the axial ligands are systematically modified from C to N to O to S atoms. Analyses of the magnetic data and the ab initio calculations both reveal large easy-plane magnetic anisotropy (D > 0) for all four complexes. While the experimentally obtained D values do not show any clear tendency when the axial coordinated atoms change from C to N to O atoms (complexes 1-3), the largest value is for the heavier and softer S-atom-coordinated complex 4. Because of significant magnetic anisotropy, all four complexes are field-induced single-ion magnets. This work represents a delicate modification of the magnetic anisotropy by tuning the chemical environment of the metal centers.
我们在此报告了四种空气稳定的七配位单核钴（II）配合物的合成、结构、计算和磁性研究，即[Co(tdmmb)(HO)][BF]（1）、[Co(tdmmb)(CN)]·2HO（2）、[Co(tdmmb)(NCS)]（3）和[Co(tdmmb)(SPh)]（4）（tdmmb = 1,3,10,12 - 四甲基 - 1,2,11,12 - 四氮杂[3吡啶基3 - 1,10 - 菲咯啉并环 - 2,10 - 二烯；SPh = 苯硫酚阴离子）。受刚性五齿大环配体tdmmb的限制，所有这些配合物中的钴中心均处于七配位五角双锥几何构型。虽然这些配合物的赤道环境彼此非常相似，但轴向配体从碳原子系统地修饰为氮原子、氧原子和硫原子。磁性数据分析和从头算计算均表明，所有四种配合物都具有较大的易面磁各向异性（D > 0）。当轴向配位原子从碳原子变为氮原子再变为氧原子时（配合物1 - 3），实验获得的D值没有显示出任何明显的趋势，但对于较重且较软的硫原子配位的配合物4，其D值最大。由于显著的磁各向异性，所有四种配合物都是场诱导单离子磁体。这项工作通过调节金属中心的化学环境，对磁各向异性进行了精细的修饰。
