Journot Guillaume, Neier Reinhard, Stoeckli-Evans Helen
Institute of Chemistry, University of Neuchâtel, Av. de Bellevaux 51, CH-2000 Neuchâtel, Switzerland.
Institute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland.
Acta Crystallogr C Struct Chem. 2014 Jul;70(Pt 7):644-9. doi: 10.1107/S2053229614012157. Epub 2014 Jun 6.
The title compound, tetrachlorido-1κCl;2κ(3)Cl-(2,2,7,7,12,12,17,17-octamethyl-21,22,23,24-tetraazapentacyclo[16.2.1.1(3,6).1(8,11).1(13,16)]tetracosane-1κ(4)N,N',N'',N''')-μ2-oxido-diiron(III), [Fe2Cl4O(C28H52N4)], undergoes a slow phase transformation at ca 173 K from monoclinic space group P2(1)/n, denoted form (I), to the maximal non-isomorphic subgroup, triclinic space group P1, denoted form (II), which is accompanied by nonmerohedral twinning [twin fractions of 0.693 (4) and 0.307 (4)]. The transformation was found to be reversible, as on raising the temperature the crystal reverted to monoclinic form (I). In the asymmetric unit of form (I), Z' = 1, while in form (II), Z' = 2, with a very small reduction (ca 1.8%) in the unit-cell volume. The two independent molecules (A and B) in form (II) are related by a pseudo-twofold screw axis along the b axis. The molecular overlay of molecule A on molecule B has an r.m.s. deviation of 0.353 Å, with the largest distance between two equivalent atoms being 1.202 Å. The reaction of calix[4]pyrrolidine, the fully reduced form of meso-octamethylporphyrinogen, with FeCl3 gave a red-brown solid that was recrystallized from ethanol in air, resulting in the formation of the title compound. In both forms, (I) and (II), the Fe(III) atoms are coordinated to the macrocyclic ligand and have distorted octahedral FeN4OCl coordination spheres. These Fe(III) atoms lie out of the mean plane of the four N atoms, displaced towards the O atom of the [OFeCl3] unit by 0.2265 (5) Å in form (I), and by 0.2210 (14) and 0.2089 (14) Å, respectively, in the two independent molecules (A and B) of form (II). The geometry of the [OFeCl3] units are similar, with each Fe(III) atom having a tetrahedral coordination sphere. The NH H atoms are directed below the planes of the macrocycles and are hydrogen bonded to the coordinated Cl(-) ions. There are also intramolecular C-H···Cl hydrogen bonds present in both (I) and (II). In form (I), there are no significant intermolecular interactions present. In form (II), the individual molecules are arranged in alternate layers parallel to the ac plane. The B molecules are linked by a C-H···Cl hydrogen bond, forming chains along [100].
标题化合物四氯-1κCl;2κ(3)Cl-(2,2,7,7,12,12,17,17-八甲基-21,22,23,24-四氮杂五环[16.2.1.1(3,6).1(8,11).1(13,16)]二十四烷-1κ(4)N,N',N'',N''')-μ2-氧代-二铁(III)，[Fe2Cl4O(C28H52N4)]，在约173 K时经历从单斜空间群P2(1)/n（记为晶型(I)）到最大非同构子群三斜空间群P1（记为晶型(II)）的缓慢相变，此过程伴有非merohedral孪晶[孪晶分数为0.693 (4)和0.307 (4)]。发现该转变是可逆的，因为升温时晶体又变回单斜晶型(I)。在晶型(I)的不对称单元中，Z' = 1，而在晶型(II)中，Z' = 2，晶胞体积有非常小的减小（约1.8%）。晶型(II)中的两个独立分子(A和B)通过沿b轴的伪二次螺旋轴相关。分子A与分子B的分子重叠的均方根偏差为0.353 Å，两个等效原子之间的最大距离为1.202 Å。杯[4]吡咯烷（中-八甲基卟吩原的完全还原形式）与FeCl3反应得到一种红棕色固体，该固体在空气中从乙醇中重结晶，从而形成标题化合物。在两种晶型(I)和(II)中，Fe(III)原子均与大环配体配位，具有扭曲的八面体FeN4OCl配位球。这些Fe(III)原子位于四个N原子的平均平面之外，在晶型(I)中朝着[OFeCl3]单元的O原子位移0.2265 (5) Å，在晶型(II)的两个独立分子(A和B)中分别位移0.2210 (14)和0.2089 (14) Å。[OFeCl3]单元的几何结构相似，每个Fe(III)原子具有四面体配位球。NH H原子指向大环平面下方，并与配位的Cl(-)离子形成氢键。在(I)和(II)中也存在分子内C-H···Cl氢键。在晶型(I)中，不存在显著的分子间相互作用。在晶型(II)中，各个分子平行于ac平面交替排列。B分子通过C-H···Cl氢键相连，沿[100]方向形成链。
