The reaction of 4-aminopyridine (4-AP) with ICl in a 1:1 molar ratio in CH₂Cl₂ produced the expected charge-transfer complex [4-NH₂-1λ⁴-C₅H₄N-1-ICl] (1·ICl) and the ionic species [(4-NH₂-1λ⁴-C₅H₄N)₂-1μ-I⁺][Cl^–] (2·Cl^–) in a 2:1 relation, as indicated by ¹H NMR spectroscopy in solution. In contrast, only the ionic compound [(4-NH₂-1λ⁴-C₅H₄N)₂-1μ-I⁺][IBr₂^–] (2·IBr₂^–) was observed in the analogous reaction with IBr. The reaction between 4-AP and I₂ in a 1:1 molar ratio also afforded two components, one of which was identified as the congeneric cation in [(4-NH₂-1λ⁴-C₅H₄N)₂-1μ-I⁺][I₇^–] (2·I₇^–) that contains a polyiodide anion as a result of transformation in a 1:2 molar ratio between the starting materials. In all of these ionic products, the crystal structures feature an iodonium ion, I⁺, trapped between two 4-AP rings through N···I⁺···N contact. Surprisingly, the reaction of 4-AP with Br₂ in CH₂Cl₂ resulted in an immediate protonation of the 4-aminopyridine (¹H NMR) and [4-NH₂-1λ⁴-C₅H₄N-1-H⁺][Br^–] (3·Br^–) was characterized as the main product. A subsequent peculiar bromination–dimerization process afforded the novel pyridyl-pyridinium cations {3,3′,5′-Br₃-1λ⁴-[1,2′-(C₅H₄N)₂]-4,4′-(NH₂)₂}⁺[X^–] (4·Br^–, 4·Br₃^–) and {3′,5′-Br₂-1λ⁴-[1,2′-(C₅H₄N)₂]-4,4′-(NH₂)₂}⁺[X^–] (5·Br^–, 5·Br₃^–). Compounds 1–5 as well as two protonated species, [4-NH₂-1λ⁴-C₅H₄N-1-H⁺]₂[Cl^–][I₃^–] (3₂·Cl^–·I₃^–) and [(4-NH₂-1λ⁴-C₅H₄N)₂-1μ-H⁺][I^–] (6·I^–), all display extended 3D networks supported by halogen and hydrogen bonding in the solid state.

中文翻译：

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4-氨基吡啶与卤素和卤素间的反应性：弱相互作用支持4-氨基吡啶和4-氨基吡啶鎓网络

4-氨基吡啶（4-AP）与ICl的的在1中的反应：在CH 1的摩尔比₂氯₂产生预期的电荷转移络合物[4-NH ₂ -1 λ ⁴ -C ₅ ħ ₄ N-1- ICl的]（1 ·ICL）和离子物种[（4- NH ₂ -1 λ ⁴ -C ₅ ħ ₄ N）₂ -1μ-I ⁺ ] [氯^- （2 ·氯^- ）以2：1如溶液中的¹ H NMR光谱所示。相比之下，只有离子性化合物[（4- NH ₂ -1 λ⁴ -C ₅ ħ ₄ N）₂ -1μ-I ⁺ ] [IBR ₂ ^- ]（2 ·IBR ₂ ^- ）是在与IBR的类似反应观察到的。4-AP和我之间的反应₂中以1：1的摩尔比也得到两个组分，其中之一被确定为[（4- NH的同类阳离子₂ -1 λ ⁴ -C ₅ ħ ₄ N）₂ - 1μ-I ⁺ ] [I ₇ ^– ]（2 ·I ₇ ^–），由于原料之间以1：2的摩尔比转化而含有聚碘阴离子。在所有这些离子产物中，晶体结构都具有一个碘鎓离子I ⁺，通过N··I ⁺ ···N接触被困在两个4-AP环之间。令人惊讶地，4-AP与溴反应₂在CH ₂氯₂导致的4-氨基吡啶的直接质子化（¹ 1 H NMR）和[4-NH ₂ -1 λ ⁴ -C ₅ ħ ₄ N-1- H ⁺ ] [Br ^– ]（3 ·Br ^–）被定为主要产品。随后奇特溴化二聚化过程，得到新颖的吡啶基-吡啶鎓阳离子{3,3'，5'-溴₃ -1 λ ⁴ - [1,2' - （C ₅ H ^ ₄ N）₂ ] -4,4' - （NH ₂）₂ } ⁺ [X ^- ]（4 ·溴^-，4 ·溴₃ ^-）和{3'，5'-溴₂ -1 λ ⁴ - [1,2' - （C ₅ H ^ ₄ N）₂ ] -4,4'-（NH ₂）₂ } ⁺ [X^– ]（5 ·Br ^–，5 ·Br ₃ ^–）。化合物1 - 5以及两个质子化物种，[4-NH ₂ -1 λ ⁴ -C ₅ ħ ₄ N-1-H ⁺ ] ₂ [氯^- ] [I ₃ ^- ]（3 ₂ ·氯^- ·I ₃ ^-）和[（4-NH ₂ -1 λ ⁴ -C ₅ ħ ₄ N）₂ -1μ-H ⁺ ] [I^– ]（6 ·I ^–），所有显示的3D扩展网络均受固态卤素和氢键的支持。