Undecaphenylcorroles

A first major study of undecaphenylcorrole (UPC) derivatives is presented. Three different Cu-UPC derivatives with different para substituents X (X = CF3, H, CH3) on the β-aryl groups were synthesized via Suzuki–Miyaura coupling of Cu­[Br8TPC] and the appropriate arylboronic acid. A single-crystal X-ray structure of the X = CF3 complex revealed a distinctly saddled macrocycle conformation with adjacent pyrrole rings tilted by ∼60–66° relative to one another (within the dipyrromethane units), which is somewhat higher than that observed for β-unsubstituted Cu-TPC derivatives but slightly lower than that observed for Cu­[Br8TPC] (∼70°) derivatives. Electrochemical and electronic absorption measurements afforded some of the first comparative insights into meso versus β substituent effects on the copper corrole core. The Soret maxima of the Cu-UPC complexes (∼440–445 nm), however, are comparable to those of Cu­[Br8TPC] derivatives and are considerably red-shifted relative to Cu-TPC derivatives. Para substituents on the β-phenyl groups were found to tune the redox potentials of copper corroles more effectively than those on meso-phenyl substituents, a somewhat surprising observation given that neither the HOMO nor LUMO has significant amplitudes at the β-pyrrolic positions.本研究首次针对十一苯基咔咯（undecaphenylcorrole, UPC）衍生物开展了一项重要的系统性研究。通过铜溴代八苯基咔咯（Cu[Br8TPC]）与对应芳基硼酸的铃木-宫浦（Suzuki–Miyaura）偶联反应，合成了三种β-芳基对位带有不同取代基X（X=CF3、H、CH3）的铜-UPC衍生物。对X=CF3的配合物进行单晶X射线结构解析后发现，其大环构象呈显著马鞍形，二吡咯甲烷单元内相邻吡咯环的相对倾斜角约为60°~66°，该角度略高于β位未取代的铜-TPC衍生物，但略低于铜溴代八苯基咔咯（Cu[Br8TPC]）衍生物的倾斜角（约70°）。电化学测试与电子吸收光谱表征首次为探究铜咔咯核上的中位（meso）与β位取代基效应提供了对比分析依据。不过，铜-UPC配合物的索特带最大值（约440~445 nm）与铜溴代八苯基咔咯（Cu[Br8TPC]）衍生物的索特带最大值相当，且相较铜-TPC衍生物发生了显著红移。研究发现，β-苯基对位取代基对铜咔咯氧化还原电位的调控效果优于中位苯基取代基；鉴于最高占据分子轨道（Highest Occupied Molecular Orbital, HOMO）与最低未占据分子轨道（Lowest Unoccupied Molecular Orbital, LUMO）在β-吡咯位点均无显著轨道振幅，这一观测结果略显意外。