We revealed the effects of the substituents in ligands on properties of Phebox-aluminum complexes. The substituents at the 4-position of Phebox ligands effectively influenced the Lewis acidity via the conjugation between the vacant orbital on the Al atom and π* orbital of the benzene ring, which is supported by DFT calculation. The catalytic activity was also tuned, and series of substituted Phebox-Al(ClO₄)₂ effectively catalyzed hydroboration of benzaldehyde. In addition, an unexpected photocatalytic activity of Phebox-Al complexes was found and applied to the hydrodebromination of a 4-bromo benzoic ester.

中文翻译：

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苯骨架上的取代基调节苯酚-铝配合物的路易斯酸度和芳基溴化物加氢脱溴的意外光催化活性

我们揭示了配体中取代基对Phebox-铝配合物性能的影响。Phebox配体的4位上的取代基通过Al原子上的空位轨道与苯环的π*轨道之间的共轭作用，有效地影响了Lewis酸度，这得到DFT计算的支持。还调节了催化活性，一系列取代的Phebox-Al（ClO ₄）₂有效催化了苯甲醛的硼氢化。另外，发现了Phebox-Al配合物出乎意料的光催化活性，并将其用于4-溴苯甲酸酯的加氢脱溴。