In order to examine the possibility of controlling formation of hydrogen bonded hexacyanoferrous networks through combination of hydrogen and halogen bonding, seven new crystalline compounds were obtained by reacting hexacyanoferrous acid (H₄[Fe(CN)₆]) with seven halogenopyridines. The (protonated) halogenopyridines were present in all seven obtained solids, and the extent in which they participate in halogen bonding varied with the halogen atom (Cl, Br and I) and the geometry of the halogenopyridines (o-, m- or p-). Iodopyridines have been found to always form halogen bonds with the cyano groups of the anions, while neither chloropyridine used in this study was found to act as a halogen bond donor. Of the prepared solids, four comprise hydrogen bonded hexacyanoferrate networks achieved by direct binding of H₂[Fe(CN)₆]²⁻ and H₃[Fe(CN)₆]⁻ anions through [Fe–CN⋯H⋯NC–Fe] hydrogen bonds into 2D and 3D networks respectively, two are formed from H₂[Fe(CN)₆]²⁻ anions bridged by water molecules, and one from [Fe(CN)₆]⁴⁻ anions bridged by H₃O⁺ cations. This variability in hydrogen bonding patterns can be brought into connection with different halogen bonding proclivities of the halopyridinium cations.

中文翻译：

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卤素键合对卤代吡啶类六氰铁酸酯中质子化六氰铁酸酯网络的影响

为了检验通过氢键和卤素键的组合控制氢键合六氰基亚铁网络形成的可能性，通过使六氰基亚铁酸（H ₄ [Fe（CN）₆ ]）与七个卤代吡啶反应获得了七个新的结晶化合物。（质子化）卤代吡啶存在于所有七个固体中，它们参与卤素键合的程度随卤素原子（Cl，Br和I）和卤代吡啶的几何形状（o-，m-或p-）。已发现碘吡啶总是与阴离子的氰基形成卤素键，而本研究中使用的氯吡啶均未发现可作为卤素键供体。在制备的固体中，有四个包含氢键合的六氰合铁酸盐网络，该网络通过H ₂ [Fe（CN）₆ ] ^2-和H ₃ [Fe（CN）₆ ] ^-阴离子通过[Fe-CN⋯H⋯NC-Fe直接结合而实现]氢键分别进入2D和3D网络，两个由水分子桥接的H ₂ [Fe（CN）₆ ] ^2-阴离子形成，一个由H ₃ O桥接的[Fe（CN）₆ ] ^4-阴离子形成。⁺阳离子。氢键结合模式的这种可变性可以与卤吡啶鎓阳离子的不同卤素键结合倾向联系在一起。