Novel near-IR-absorbing porphyrazines - tetrakis-(5,7,7-trimethyl-6,7-dihydro-1H-1,4-diazepino)porphyrazines (Me12Dz4PAMgII and Me12Dz4PAH2) and their cyclohexyl derivatives (Cy8Dz4PAMgII and Cy8Dz4PAH2) were prepared by template cyclotetramerization of the corresponding 6,7-dihydro-1H-1,4-diazepine-2,3-dicarbonitriles in the presence of magnesium or lithium butoxides. The resulting macrocycles were characterized using IR, MALDI TOF, 1H NMR, UV-Vis-spectroscopy and cyclic voltamperometry. The presence in the fused 6,7-dihydro-1H-1,4-diazepine rings of the electron acceptor imino and donor secondary amino groups leads to strong polarization of the π-chromophore and shifts the Q band maxima in the near IR region (710-740 nm for the MgII complexes, 750-770 nm for the metal free macrocycles). The NH-groups in the diazepine fragments participating in intramolecular charge transfer (ICT) strongly quench the fluorescence. Spectrophotometric titration, 1H NMR measurements and quantum chemical molecular modeling indicate that protonation of the diazepine rings which occurs on the imino nitrogen atoms switches off the ICT effect and increases the fluorescence quantum yields by 2-4 times.

中文翻译：

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带环二氮卓环的卟啉。5.近红外吸收四（6,7-二氢-1H-1,4-二氮杂萘）卟啉及其酸解对其光谱性质的影响

制备了新的近红外吸收卟啉-四（-（5,7,7-三甲基-6,7-二氢-1H-1,4-二氮杂庚醇）卟啉（Me12Dz4PAMgII和Me12Dz4PAH2）及其环己基衍生物（Cy8Dz4PAMgII和Cy8Dz4PAH2）通过在丁醇镁或锂的存在下，将相应的6,7-二氢-1H-1,4-二氮杂-2,3-二腈进行模板环四聚。使用IR，MALDI TOF，1 H NMR，UV-Vis光谱和循环伏安法对所得的大环化合物进行表征。电子受体亚氨基和供体仲氨基在稠合的6,7-二氢-1H-1,4-二氮杂环上的存在会导致π发色团的强烈极化并使Q带的最大值在近红外区移动（ MgII配合物为710-740 nm，无金属大环化合物为750-770 nm。参与分子内电荷转移（ICT）的二氮杂fragments片段中的NH-基团强烈淬灭了荧光。分光光度滴定，1 H NMR测量和量子化学分子模型表明，亚氨基氮原子上发生的二氮杂环的质子化关闭了ICT效应，并使荧光量子产率提高了2-4倍。