Thermal and Photoinduced Spin Crossover in a Mononuclear Iron(II) Complex with a Bis(pyrazolyl)pyridine Type of Ligand
Thermal and Photoinduced Spin Crossover in a Mononuclear Iron(II) Complex with a Bis(pyrazolyl)pyridine Type of Ligand
复制标题
单核铁 (II) 配合物与双(吡唑基)吡啶型配体中的热和光致自旋交叉
DOI：
10.1002/ejic.201201123
复制
发表时间：
2013
影响因子：
2.3
通讯作者：
M. Ruben
中科院分区：
文献类型：
--
作者：
Ivan Šalitroš;O. Fuhr;R. Kruk;J. Pavlik;L. Pogány;B. Schäfer;Miroslav Tatarko;R. Boča;W. Linert;M. Ruben
制备了一种通式为[Fe(L)2](ClO4)2 {L = 4-[2,6-双（吡唑-1-基）吡啶-4-基]苯甲醛}的单核铁（II）化合物1，并对其进行了结构表征。单晶x射线结构分析显示，单晶胞内存在一个配合物[Fe(L)2]2+和两个ClO4 -反阴离子。配位多面体FeN6内的键长和键角表明中心铁（II）金属离子在T = 180 K时处于低自旋状态。磁研究阐明了T1/2 = 285 K时的自旋交叉。结合类伊辛模型，实验磁化率数据可以很好地拟合居里定律。利用变温远红外光谱、可见光光谱和穆斯堡尔光谱进一步研究了自旋交叉的室温特性。在10k下进行激光照射，产生完全的低自旋到高自旋的光转换。随后的温度依赖性研究表明存在高达TLIESST = 70 K的光激发亚稳HS态（LIESST =光诱导激发自旋态捕获）以及宽度为10 K的光诱导热滞后环的存在。
A mononuclear iron(II) compound 1 of the general formula [Fe(L)2](ClO4)2 {L = 4-[2,6-bis(pyrazol-1-yl)pyridin-4-yl]benzaldehyde} was prepared and structurally characterised. Single-crystal X-ray structure analysis revealed the presence of a complex dication [Fe(L)2]2+ and two ClO4– counteranions within the unit cell. The bond lengths and angles within the coordination polyhedron FeN6 indicate the low-spin state of the central iron(II) metal ion at T = 180 K. Magnetic investigations elucidate spin crossover with T1/2 = 285 K. The experimental magnetic susceptibility data could be satisfactorily fitted with the Curie law in combination with the Ising-like model. The room-temperature character of the spin crossover was further studied by variable-temperature far-IR, Vis and Mossbauer spectroscopy. Laser irradiation of 1 carried out at 10 K gives rise to a complete low-spin to high-spin photoconversion. A subsequent temperature-dependent investigation revealed the existence of a photoexcited metastable HS state up to TLIESST = 70 K (LIESST = light-induced excited-spin-state trapping) as well as the presence of a light-induced thermal hysteresis loop with a width of 10 K.