Porphyrins with exocyclic rings. 14. - Synthesis of tetraacenaphthoporphyrins, a new family of highly conjugated porphyrins with record-breaking long-wavelength electronic absorptions
Porphyrins with exocyclic rings. 14. - Synthesis of tetraacenaphthoporphyrins, a new family of highly conjugated porphyrins with record-breaking long-wavelength electronic absorptions
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DOI：
10.1021/jo991730w
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发表时间：
2000-03-10
影响因子：
3.6
通讯作者：
Lash, TD
中科院分区：
文献类型：
--
作者：
Spence, JD;Lash, TD
卟啉的Soret带通常在近紫外线下在约400 nm处观察到，并且在文献中先前已经报道了具有在500 nm以上的值处的该主要吸收带的“非扩展”卟啉的一些实例。与芳环系统如萘、蒽或菲的环稠合通常仅产生对该诊断吸收带的微小红移。本文报道了一系列四苊卟啉及其金属螯合物的合成。苊烯环系统的紧凑性质允许使用Lindsey方法引入内消旋取代基，内消旋-四苯基卟啉10a显示在556 nm处存在Soret带，而10 f和10 g中的对甲氧基和对硝基取代基分别将该带进一步移动到560和570 nm。添加TFA产生相应的dications与略高波长Soret带在565，573，和588上午。这些值相比，525个月的双阳离子的四苊烯8，它缺乏内消旋芳基取代基，表明空间拥挤和其产生的大环构象的扭曲是负责这些位移的一个显着的，虽然小部分。镍（II），铜（II），和锌螯合物的10 a产生Soret;带在528，545，和558 nm，分别，表明增加的趋势在整个周期表中的金属卟啉的红移保留了这个系列。铅（II）螯合物19 d产生额外的“超”位移，使Soret带达到604 nm。通过在meso位引入四个苯乙炔基取代基，可以实现类似的fed位移，并且这种高度共轭的卟啉（20）也在604 nm处显示Soret吸收带，而相应的dicatian在629 nm处提供该吸收带。由于铅螯合作用，基本上加性的“超”位移使相关铅（II）络合物22 d的Soret带达到642 nm。这些效应是迄今为止观察到的最大的真正的卟啉，并表明Soret带可以微调到几乎任何部分的可见光谱。
The Soret band for porphyrins is usually observed in the near-ultraviolet at approximately 400 nm, and few examples of "nonexpanded" porphyrins with this major absorption band at values above 500 nm have previously been reported in the literature. Ring fusion with aromatic ring systems such as naphthalene, anthracene, or phenanthrene generally only produces minor bathochromic shifts to this diagnostic absorption band. In this paper, the synthesis of a series of tetraacenaphthoporphyrins and their metal chelates is reported. The compact nature of the acenaphthylene ring system allows the introduction of meso substituents using the Lindsey methodology, meso-Tetraphenylporphyrin 10a shows the presence of a Soret band at 556 nm, while p-methoxy and p-nitro substituents in 10f and 10g, respectively, further shift this band to 560 and 570 nm. Addition of TFA produces the corresponding dications with slightly higher wavelength Soret bands at 565, 573, and 588 am. These values compare to 525 mo for the dication of tetraacenaphthylene 8, which lacks the meso-aryl substituents, indicating that steric crowding and its resulting distortion of the macrocyclic conformation is responsible for a significant albeit minor portion of these shifts. The nickel(II), copper(II), and zinc chelates of 10a produce Soret; bands at 528, 545, and 558 nm, respectively, demonstrating that the trend for increasing red shifts in metalloporphyrins across the periodic table is retained for this series. The lead(II) chelate 19d gave an additional "hyper" shift that brought the Soret band to 604, nm. A similar fed shift could be achieved by introducing four phenylethynyl substituents at the meso positions, and this highly conjugated porphyrin (20) also showed a Soret band at 604 nm, while the corresponding dicatian afforded this absorption band at 629 nm. The essentially additive "hyper" shift due to lead chelation brought the Soret band for the related lead(II) complex 22d to 642 nm. These effects are by far the largest ever observed for true porphyrins and demonstrate that the Soret band can be fined tuned to virtually any part of the visible spectrum.