Department of Chemistry , Indian Institute of Technology Roorkee , Roorkee 247667 , India.
Inorg Chem. 2018 Sep 17;57(18):11349-11360. doi: 10.1021/acs.inorgchem.8b00798. Epub 2018 Sep 4.
Several ruffled β-to- ortho-phenyl monofused metalloporphyrins (MMFPs) with 1,3-indanedione functionality have been synthesized by oxidative fusion of free base trans-chlorins via nickel insertion followed by the skeletal rearrangement of macrocycle. The synthesized monofused porphyrins exhibited red-shifted electronic spectral features as compared to precursor, trans-chlorins or structurally related unfused porphyrins (mono/tri-β-substituted porphyrins) due to extended π-conjugation and nonplanar conformation of the macrocyclic core. Four of the synthesized porphyrins were structurally characterized by X-ray diffraction analysis. Ring fusion resulted in twisted macrocyclic conformation, and the twist angles (the angle between 24-atom core and fused part) were found to be in the range of 20.97° to 27.97°. NiMFP(IND)Ph (3b) exhibited modestly ruffled conformation of the macrocyclic core which was further confirmed by higher Δ24 (0.362 Å) and ΔC (0.279 Å) values. Free base monofused porphyrins have shown upfield shifted (Δδ = 0.27-0.29 ppm) inner core NHs as compared to precursors ( trans-chlorins), whereas much downfield shifted (Δδ = 0.9 ppm) as compared to HTPP. Electron-rich Ni(II) complexes, that is, NiMFP(IND)R (where R = H and Ph) (1b and 3b), exhibited metal centered oxidation (Ni/Ni) due to extended π-conjugation of macrocyclic core and electron-donating β-substituents. Facile synthesis with good yields (60-90%), unexpected nickel-induced oxidative fusion, and selective conversion of trans-chlorins into monofused Ni-porphyrins are the significant features of the present work.
几种具有 1,3-茚二酮功能的皱状β-邻苯基单稠合金属卟啉（MMFP）已通过自由碱基反式氯的氧化融合通过镍插入合成，然后通过大环骨架重排。与前体、反式氯或结构相关的未稠合卟啉（单/三-β-取代卟啉）相比，合成的单稠合卟啉由于扩展的π-共轭和大环核心的非平面构象，表现出电子光谱特征的红移。通过 X 射线衍射分析对其中四种卟啉进行了结构表征。环融合导致扭曲的大环构象，并且发现扭曲角（24 原子核心与融合部分之间的角度）在 20.97°至 27.97°的范围内。NiMFP（IND）Ph（3b）表现出适度的大环核心皱状构象，这进一步通过更高的Δ24（0.362Å）和ΔC（0.279Å）值得到证实。与前体（反式氯）相比，自由碱基单稠合卟啉的内核心 NH 发生了向上场位移（Δδ=0.27-0.29ppm），而与 HTPP 相比，发生了更大的向下场位移（Δδ=0.9ppm）。富电子的 Ni（II）配合物，即 NiMFP（IND）R（其中 R=H 和 Ph）（1b 和 3b），由于大环核心和供电子β-取代基的扩展π-共轭，表现出金属中心氧化（Ni/Ni）。高产率（60-90%）、意外的镍诱导氧化融合以及反式氯容易转化为单稠合 Ni-卟啉是本工作的显著特点。
