The Inhibited Dehydration Polycondensation Tendency of a Titanocene Aqua Complex Attributed to the Formation of Hydrogen Bonds Between the Ligand Water and Py-NO: Mechanism and Application

Abstract

Titanocene aqua complexes (TACs) demonstrate versatile activities that critically depend on maintaining their molecular integrity in aqueous media. However, the strong oxophilicity of Ti(IV) centers renders these complexes prone to undesirable dehydration-condensation reactions, which severely compromise their structural stability. To address this challenge, we developed a simple yet effective strategy for dramatically stabilizing TACs in aqueous environments through the introduction of pyridine-N-oxides (Py-NOs) as auxiliary ligands. Comprehensive mechanistic investigations, including spectroscopic analyses and DFT calculations, reveal that the enhanced stability originates primarily from the formation of intermolecular hydrogen bonds between TACs and Py-NOs. These interactions effectively suppress Ti(IV)-mediated hydrolysis pathways while preserving the complexes’ functionality.