Grunert C Matthias, Schweifer Johannes, Weinberger Peter, Linert Wolfgang, Mereiter Kurt, Hilscher Gerfried, Müller Martin, Wiesinger Günter, van Koningsbruggen Petra J
Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-AC, A-1060 Vienna, Austria.
Inorg Chem. 2004 Jan 12;43(1):155-65. doi: 10.1021/ic034452z.
[micro-Tris(1,4-bis(tetrazol-1-yl)butane-N4,N4')iron(II)] bis(hexafluorophosphate), Fe(btzb)(3)(2), crystallizes in a three-dimensional 3-fold interlocked structure featuring a sharp two-step spin-crossover behavior. The spin conversion takes place between 164 and 182 K showing a discontinuity at about T(1/2) = 174 K and a hysteresis of about 4 K between T(1/2) and the low-spin state. The spin transition has been independently followed by magnetic susceptibility measurements, (57)Fe-Mössbauer spectroscopy, and variable temperature far and midrange FTIR spectroscopy. The title compound crystallizes in the trigonal space group P3 (No. 147) with a unit cell content of one formula unit plus a small amount of disordered solvent. The lattice parameters were determined by X-ray diffraction at several temperatures between 100 and 300 K. Complete crystal structures were resolved for 9 of these temperatures between 100 (only low spin, LS) and 300 K (only high spin, HS), Z = 1 Fe(btzb)(3)(2): 300 K (HS), a = 11.258(6) A, c = 8.948(6) A, V = 982.2(10) A(3); 100 K (LS), a = 10.989(3) A, c = 8.702(2) A, V = 910.1(4) A(3). The molecular structure consists of octahedral coordinated iron(II) centers bridged by six N4,N4' coordinating bis(tetrazole) ligands to form three 3-dimensional networks. Each of these three networks is symmetry related and interpenetrates each other within a unit cell to form the interlocked structure. The Fe-N bond lengths change between 1.993(1) A at 100 K in the LS state and 2.193(2) A at 300 K in the HS state. The nearest Fe separation is along the c-axis and identical with the lattice parameter c.
双（六氟磷酸）[三（1,4 - 双（四唑 - 1 - 基）丁烷 - N4,N4'）铁（II）]，Fe(btzb)(3)(2)，以三维三重互锁结构结晶，具有明显的两步自旋交叉行为。自旋转换发生在164至182 K之间，在约T(1/2) = 174 K处出现不连续性，并且在T(1/2)与低自旋态之间存在约4 K的磁滞现象。通过磁化率测量、（57）Fe - 穆斯堡尔光谱以及变温远红外和中红外光谱独立跟踪了自旋转变。标题化合物结晶于三方空间群P3（编号147），晶胞内容为一个化学式单元加上少量无序溶剂。在100至300 K之间的几个温度下通过X射线衍射确定了晶格参数。在100（仅低自旋，LS）至300 K（仅高自旋，HS）之间的这些温度中的9个温度下解析了完整的晶体结构，Z = 1 Fe(btzb)(3)(2)：300 K（HS），a = 11.258(6) Å，c = 8.948(6) Å，V = 982.2(10) Å(3)；100 K（LS），a = 10.989(3) Å，c = 8.702(2) Å，V = 910.1(4) Å(3)。分子结构由八面体配位的铁（II）中心组成，通过六个N4,N4'配位的双（四唑）配体桥连，形成三个三维网络。这三个网络中的每一个都是对称相关的，并且在一个晶胞内相互贯穿形成互锁结构。Fe - N键长在LS态下100 K时为1.993(1) Å，在HS态下300 K时为2.193(2) Å。最近的Fe间距沿c轴，与晶格参数c相同。
