Bromine‐terminated tripyrrin, a partial porphyrin structure, is synthesized by saponification of tripyrrane dimethyl ester and subsequent treatment with an aqueous bromine solution. In this reaction, bromine serves as a decarboxylating, oxidizing, and brominating agent. The resulting ligand can be coordinated with a metal ion such as Re⁺, which is not easily encapsulated in porphyrin cores. Nucleophilic substitution reactions at the brominated positions were also investigated, particularly the substitution with diethylamino and/or ethoxy groups. Structural elucidation was carried out by X‐ray crystallography, which revealed the flatter frameworks of the free bases and distorted geometries of the metal complexes. Such chemical modifications dramatically influence the photophysical properties, such as UV‐visible absorption, and are promising for bio‐related applications such as SPECT imaging probes.

中文翻译：

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溴封端的β-烷基取代的三联吡啶：反应性，配位能力以及作为可扩展的无环寡聚吡咯配体的作用

通过将三吡喃二甲酯皂化并随后用溴水溶液处理来合成溴封端的三联卟啉（部分卟啉结构）。在该反应中，溴用作脱羧，氧化剂和溴化剂。生成的配体可以与金属离子（例如Re ⁺，它不容易封装在卟啉核中。还研究了溴化位置的亲核取代反应，特别是二乙氨基和/或乙氧基的取代。通过X射线晶体学对结构进行了阐明，揭示了游离碱的平面构架更平坦，金属配合物的几何形状也发生了扭曲。这种化学修饰会极大地影响光物理性质，例如UV可见光吸收，并且对于与生物相​​关的应用（例如SPECT成像探针）很有希望。