Al-Ktaifani Mahmoud, Rukiah Mwaffak
Department of Chemistry, Atomic Energy Commission of Syria, PO Box 6091, Damascus, Syrian Arab Republic.
Acta Crystallogr C. 2012 Sep;68(Pt 9):m246-50. doi: 10.1107/S0108270112031885. Epub 2012 Aug 1.
In order to explore the potential propensity of the 1,1'-methylenedipyridinium dication to form organic-inorganic hybrid ionic compounds by reaction with the appropriate halide metal salt, the organic-inorganic hybrid salts 1,1'-methylenedipyridinium tetrachloridocuprate(II), (C(11)H(12)N(2))[CuCl(4)], (I), and 1,1'-methylenedipyridinium bis[tetrachloridoaurate(III)], (C(11)H(12)N(2))AuCl(4), (II), were obtained by treatment of 1,1'-methylenedipyridinium dichloride with CuCl(2) and Na[AuCl(4)], respectively. Both hybrid salts were isolated as pure compounds, fully characterized by multinuclear NMR spectroscopy and their molecular structures confirmed by powder X-ray diffraction studies. The crystal structures consist of discrete 1,1'-methylenedipyridinium dications and CuCl(4) and AuCl(4) anions for (I) and (II), respectively. As expected, the dications form a butterfly shape; the Cu(II) centre of CuCl(4) has a distorted tetrahedral configuration and the Au(III) centre of AuCl(4) shows a square-planar coordination. The ionic species of (I) and the dication of (II) each have twofold axial symmetry, while the two AuCl(4) anions are located on a mirror-plane site. Both crystal structures are stabilized by intermolecular C-H···Cl hydrogen bonds and also by Cl···π interactions. It is noteworthy that, while the average intermolecular centroid-centroid pyridinium ring distance in (I) is 3.643 (8) Å, giving strong evidence for noncovalent π-π ring interactions, for (II), the shortest centroid-centroid distance between pyridinium rings of 5.502 (9) Å is too long for any significant π-π ring interactions, which might be due to the bulk of the two AuCl(4) anions.
为了探究1,1'-亚甲基二吡啶二价阳离子与合适的卤化金属盐反应形成有机-无机杂化离子化合物的潜在倾向，通过分别用CuCl₂和Na[AuCl₄]处理1,1'-亚甲基二吡啶二氯化物，得到了有机-无机杂化盐1,1'-亚甲基二吡啶四氯合铜(II)酸盐(C₁₁H₁₂N₂)[CuCl₄] (I)和1,1'-亚甲基二吡啶双四氯合金(III)酸盐[AuCl₄]₂ (II)。两种杂化盐均以纯化合物形式分离出来，通过多核NMR光谱进行了全面表征，并通过粉末X射线衍射研究确定了它们的分子结构。晶体结构分别由离散的1,1'-亚甲基二吡啶二价阳离子和[CuCl₄]²⁻以及[AuCl₄]⁻阴离子组成，对应于(I)和(II)。正如预期的那样，二价阳离子形成蝴蝶形状；[CuCl₄]²⁻的Cu(II)中心具有扭曲的四面体构型，[AuCl₄]⁻的Au(III)中心呈现平面正方形配位。(I)的离子物种和(II)的二价阳离子各自具有二重轴对称性，而两个[AuCl₄]⁻阴离子位于镜面位置。两种晶体结构均通过分子间C-H···Cl氢键以及Cl···π相互作用得以稳定。值得注意的是，虽然(I)中吡啶环的平均分子间质心-质心距离为3.643(8) Å，有力地证明了非共价π-π环相互作用，但对于(II)，吡啶环之间最短的质心-质心距离为5.502(9) Å，对于任何显著的π-π环相互作用来说都太长了，这可能是由于两个[AuCl₄]⁻阴离子的体积较大所致。
