Optical investigation of spin-crossover in cobalt(II) bis-terpy complexes
Optical investigation of spin-crossover in cobalt(II) bis-terpy complexes
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钴(II)双锥配合物中自旋交叉的光学研究
DOI：
10.1016/j.ica.2007.06.022
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发表时间：
2007
影响因子：
2.8
通讯作者：
A. Hauser
中科院分区：
文献类型：
--
作者：
C. Enachescu;Itana Krivokapic;M. Zerara;J. Real;Nahid Amstutz;A. Hauser
根据光谱和磁化率测量的实验数据，分析了[Co(terpy)2]2+配合物（terpy=2,2′:6′,2″-三联吡啶）的自旋跃迁。 [Co(terpy)2](ClO4)2 的单晶吸收光谱在 14400cm−1 处显示出不对称吸收带，具有自旋允许的 d-d 跃迁的典型强度和热自旋跃迁的典型温度行为。单晶吸收光谱表明，在该化合物中，配合物在所有温度下基本上都处于高自旋状态。然而，在低自旋 MLCT 转变区域观察到的强度随着温度的升高而增加，这意味着低自旋态的部分热布居在室温下高达约 10%。最后，给出了分散在 KBr 盘中的 [Co(terpy)2](ClO4)2 在脉冲激光激发后的高自旋→低自旋弛豫曲线，并作为密切相关的 [Co(4-terpyridone)2](ClO4)2 自旋交叉化合物的比较。
The spin transition of the [Co(terpy)2]2+complex (terpy=2,2′:6′,2″-terpyridine) is analysed based on experimental data from optical spectroscopy and magnetic susceptibility measurements. The single crystal absorption spectrum of [Co(terpy)2](ClO4)2shows an asymmetric absorption band at 14400cm−1with an intensity typical for a spin-allowed d–d transition and a temperature behaviour typical for a thermal spin transition. The single crystal absorption spectra of suggest that in this compound, the complex is essentially in the high-spin state at all temperatures. However, the increase in intensity observed in the region of the low-spin MLCT transition with increasing temperature implies an unusual partial thermal population of the low-spin state of up to about 10% at room temperature. Finally, high-spin→low-spin relaxation curves following pulsed laser excitation for [Co(terpy)2](ClO4)2dispersed in KBr discs, and as a comparison for the closely related [Co(4-terpyridone)2](ClO4)2spin-crossover compound are given.