Decoding Ligand Effects in Organoaluminum Phenoxide Systems: A Multifaceted Hirshfeld Surface and Electrostatic Potential Approach

A rigid bis-hydroxyl Schiff base ligand-stabilized aluminum-phenoxide complex was designed and synthesized through structural modification of alcohol derivatives. The structural characteristics, particularly the spatial orientation of hydroxyl groups, were elucidated through single-crystal X-ray diffraction analysis, demonstrating their deterministic role in modulating the coordination geometry of the aluminum center. Quantitative Hirshfeld surface analysis demonstrated a substantial evolution in intermolecular interactions, with H⋯H contacts exhibiting significantly enhanced contributions from 57.6% (ligand) to 84.9% (complex), consistent with steric hindrance amplification resulting from the rigid ligand framework in the molecular assembly. Furthermore, molecular electrostatic potential analysis confirmed the emergence of a pronounced negative electrostatic potential region at the aluminum center (minimum: -203.84 kJ/mol), attributable to its high electronegativity. Concurrently, the formation of Al–N coordination bonds was observed to induce charge redistribution, converting the originally localized positive potential regions (e.g., +191.25 kJ/mol near oxygen atoms) into a globally negative electrostatic profile. This study systematically deciphers the cascade regulatory mechanism spanning ligand conformation, metal coordination, and electronic structure at atomic resolution, thereby establishing a theoretical framework for the rational design of highly active aluminum-based homogeneous catalysts.