Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
Dalton Trans. 2018 Oct 9;47(39):13809-13814. doi: 10.1039/c8dt02367k.
The cobalt(ii) complex incorporating π-conjugated substituent, Co(Naph-C2-terpy)22 (1; Naph-C2-terpy = 4'-(2-naphthoxy(ethoxy))-2,2':6',2''-terpyridine), exhibits an abrupt spin transition (ST) behavior (cooperative factor C = 0.91) while its solvated product, 1·2MeOH, shows gradual spin crossover (SCO) behavior (C = 0.49). Single crystal X-ray structural analyses demonstrated that the octahedral coordination core [CoN6] in 1 shows larger distortion in both high-spin and low-spin states than solvated 1·2MeOH or another two derivatives, Co(R-terpy)22 (R = 2-naphthyl (2), 9-anthracenyl (3)). The respective distortion parameters (Σ) are compared with those for previously reported SCO cobalt(ii) compounds. The highly-distorted [CoN6] core in 1 (Σ = 126 in the HS state and 101.6 in the LS state) was stabilized by strong intermolecular interactions and observed an abrupt ST behaviour.
含有π共轭取代基的钴（II）配合物，[Co（Naph-C2-terpy）2]（BF4）2（1；Naph-C2-terpy=4'-(2-萘氧基（乙氧基）)-2,2':6',2''-三联吡啶），表现出急剧的自旋转变（ST）行为（协同因子 C = 0.91），而其溶剂化产物 1·2MeOH 则表现出逐渐的自旋交叉（SCO）行为（C = 0.49）。单晶 X 射线结构分析表明，1 中的八面体配位核[CoN6]在高自旋和低自旋状态下都表现出比溶剂化 1·2MeOH 或另外两个衍生物[Co（R-terpy）2]（BF4）2（R = 2-萘基（2）、9-蒽基（3））更大的扭曲。比较了各自的变形参数（Σ）与先前报道的 SCO 钴（II）化合物的参数。1 中高度扭曲的[CoN6]核（在 HS 状态下的Σ=126，在 LS 状态下的Σ=101.6）通过强分子间相互作用稳定，并表现出急剧的 ST 行为。
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