Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA.
Inorg Chem. 2011 Apr 4;50(7):2782-9. doi: 10.1021/ic1018357. Epub 2011 Mar 10.
Three members of the family of trigonal bipyramidal (TBP) complexes of general formula M(tmphen)(2)M'(CN)(6) (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) or [M(3)M'(2)], which are known to exhibit thermally induced spin crossover and charge transfer, have been investigated for optical and photomagnetic properties. The light-induced excited spin-state trapping (LIESST) effect found in classical spin crossover compounds, such as [Fe(phen)(2)(NCS)(2)], was explored for the [Fe(3)Fe(2)] and [Fe(3)Co(2)] compounds. Similarly, inspired by the light-induced charge-transfer properties of K(0.2)Co(1.4)[Fe(CN)(6)]·6.9H(2)O and related Prussian blue materials, the possibility of photo-induced magnetic changes was investigated for the [Co(3)Fe(2)] TBP complex. Optical reflectivity and magnetic susceptibility measurements were used to evaluate the photoactivity of these compounds. A comparison of these data before and after light irradiation demonstrates that (i) the spin crossover of the Fe(II) centers in the [Fe(3)Fe(2)] and [Fe(3)Co(2)] analogues and the (ii) charge transfer events in the [Co(3)Fe(2)] complex occur with temperature and irradiation. In addition, photomagnetic behavior is exhibited by all three compounds. The photo-conversion efficiency has been estimated at 20% of photo-induced high spin Fe(II) centers in [Fe(3)Co(2)], 30% of paramagnetic Co(II)-Fe(III) pairs in [Co(3)Fe(2)], and less than 2% of photo-induced high spin Fe(II) centers in [Fe(3)Fe(2)].
三种具有三角双锥（TBP）结构的配合物M(tmphen)(2)M'(CN)(6)（tmphen = 3,4,7,8-四甲基-1,10-菲咯啉）或[M(3)M'(2)]（其中 M 和 M'分别为不同的金属离子）被研究了其光学和光磁性质。我们探索了光诱导激发态捕获（LIESST）效应在经典自旋交叉化合物（如[Fe(phen)(2)(NCS)(2)]）中的应用，同时也对[Fe(3)Fe(2)]和[Fe(3)Co(2)]化合物进行了研究。同样，受 K(0.2)Co(1.4)[Fe(CN)(6)]·6.9H(2)O 和相关普鲁士蓝材料的光致电荷转移性质的启发，我们研究了[Co(3)Fe(2)]TBP 配合物光诱导磁变化的可能性。我们使用光学反射率和磁化率测量来评估这些化合物的光活性。比较这些化合物在光照前后的数据表明：(i) Fe(II)中心在[Fe(3)Fe(2)]和[Fe(3)Co(2)]类似物中的自旋交叉以及 (ii) [Co(3)Fe(2)] 配合物中的电荷转移事件都与温度和辐照有关。此外，所有三种化合物都表现出光磁行为。光转化效率在[Fe(3)Co(2)]中被估计为光诱导高自旋 Fe(II)中心的 20%，在[Co(3)Fe(2)]中为顺磁 Co(II)-Fe(III)对的 30%，而在[Fe(3)Fe(2)]中则小于光诱导高自旋 Fe(II)中心的 2%。
