双二茂铁基吡咯衍生物电荷交互通道

以二茂铁炔烃为原料通过“一锅法”环加成反应合成了一系列2,5-双二茂铁基-1-苯基-吡咯衍生物, 包括: 2,5-双二茂铁基-1-(3-三氟甲基苯基)-吡咯(1), 2,5-双二茂铁基-1-(4-氟苯基)-吡咯(2), 2,5-双二茂铁基-1-苯基-吡咯(3), 2,5-双二茂铁基-1-(4-乙基苯基)-吡咯(4)和2,5-双二茂铁基-1-(4-乙氧基苯基)-吡咯(5), 使用元素分析, 傅里叶变换红外(FTIR)光谱, 质谱(MS)和核磁共振(NMR)等手段对化合物进行了结构表征. 采用循环伏安法(CV), 密度泛函理论(DFT)模拟计算研究了苯基上取代基对双二茂铁间电荷交互的影响. 研究发现第一氧化电位(E_a1), 峰电位差(ΔE)与取代基的哈米特常数(σ), 吡咯¹H NMR的化学位移(δ), 吡咯N原子自然轨道(NBO)电荷之间存在显著线性关联; 同时发现, N原子电荷密度升高, 双二茂铁间电荷交互能力减弱, N原子电荷密度降低, 双二茂铁间电荷交互能力提高. 因此这类双二茂铁基吡咯衍生物中N原子电荷密度对双二茂铁间电荷交互起着关键的影响作用.

Channel of Electronic Interactions in Diferrocenyl Pyrrole Derivatives

2,5-Diferrocenyl-1-(3-trifluorom-ethylphenyl)-pyrrole (1), 2,5-diferrocenyl-1-(4-fluorophenyl)-pyrrole (2), 2,5-diferrocenyl-1-phenyl pyrrole (3), 2,5-diferro-cenyl-1-(4-ethylphenyl)-pyrrole (4), and 2,5-diferrocenyl- 1-(4-ethoxyphenyl)-pyrrole (5) were prepared by the one-pot cycloaddition reaction of ferrocenyl alkyne. The 2,5-diferrocenyl-1-phenyl-1-pyrrole derivatives were characterized by elemental analysis, Fourier-transform infrared (FTIR) spectroscopy, mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy. The influence of substituents at the phenyl moiety on the electronic interaction was studied using cyclic voltammetry (CV) and density functional theory (DFT) calculations. A linear relationship was observed between the first oxidation potential (E_a1), oxidation potential difference (ΔE) with Hammett constant (Hammett σ) of the substituent, pyrrole ¹H NMR chemical shift (δ), and pyrrole N natural bond orbital (NBO) charge. A high N charge density weakened the electronic interaction, and vice versa. Electron transfer between the two ferrocenyl units of these diferrocenyl pyrrole derivatives was influenced by the N charge density.