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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Highly conjugated multiporphyrins: synthesis, spectroscopic and electrochemical properties
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Highly conjugated multiporphyrins: synthesis, spectroscopic and electrochemical properties

机译：高度共轭的多卟啉：合成，光谱和电化学性质

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A series of meso-to-meso ethynyl-bridged multiporphyrin arrays have been synthesized using Sonogoshira palladium-catalyzed cross-coupling reactions involving the appropriate ethynylporphyrin and iodoporphyrin precursors. The absorption spectra of these multiporphyrins show splitting of the Soret bands and significant red shifts of the Q bands as compared to the combination of the corresponding components. These conjugated multiporphyrins also show red shifts in their emission spectra as the pi-conjugation is expanded. In the electrochemical measurements, the porphyrins dimer 7 shows two 1-e(-) oxidations at E-1/2 =+ 0.63 and + 0.76 V for the first electron abstraction from the two porphyrin rings, indicating electronic communication between the two porphyrin units. The porphyrin trimer 4 exhibits the first and second 1-e(-) oxidations at E-1/2 =+ 0.68 and + 0.77 V, respectively, which correspond to the two outer porphyrins. The cyclic voltammogram of pentamer 5 shows two overlapping 1-e(-) couples at E-1/2 =+ 0.56 and + 0.66 V, and one 2-e(-) couple at E-1/2 =+ 0.86 V, for the four outer porphyrin units. These results demonstrate that in the porphyrin trimer and pentamer the individual peripheral porphyrin units are electrochemically coupled via a central porphyrin core. The UV-Vis-NIR spectra of the oxidized species of these multiporphyrins exhibit a broad intervalence charge transfer (IVCT) band in the region from 1200 to 3000 nm. The present work shows that a central porphyrin unit appended with ethynyl bridges affords strong electronic interactions between the peripheral porphyrin rings over a distance of about 15 angstrom.
机译：使用涉及合适的乙炔基卟啉和碘卟啉前体的Sonogoshira钯催化的交叉偶联反应，已经合成了一系列介孔-间位乙炔基桥接的多卟啉阵列。与相应组分的组合相比，这些多卟啉的吸收光谱显示出Soret带的分裂和Q带的显着红移。这些结合的多卟啉也随着π结合的扩展而在发射光谱中显示出红移。在电化学测量中，卟啉二聚体7在E-1 / 2 = + 0.63和+ 0.76 V处显示出两个1-e（-）氧化，用于从两个卟啉环的第一次电子提取，表明两个卟啉单元之间的电子连通。卟啉三聚体4分别在E-1 / 2 ＝ + 0.68和+ 0.77V处表现出第一和第二1-e（-）氧化，其对应于两个外部卟啉。五聚体5的循环伏安图显示在E-1 / 2 = + 0.56和+ 0.66 V时两个重叠的1-e（-）对，在E-1 / 2 = + 0.86 V时一个2-e（-）对，用于四个外部卟啉单元。这些结果表明，在卟啉三聚体和五聚体中，各个外围的卟啉单元通过中心卟啉核电化学耦合。这些多卟啉的氧化物种的UV-Vis-NIR光谱在1200至3000 nm范围内显示出较宽的间隔电荷转移（IVCT）带。本工作表明，附有乙炔基桥的中央卟啉单元在大约15埃的距离上在外围卟啉环之间提供了强电子相互作用。

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