Metal-Organic Dimerization of Dissymmetrical Ligands toward Customized Through-Space Chromophore Interactions

The pursue of good photophysical properties for organic optoelectronic materials requires a well understanding of through-space chromophore interactions, which further requires a well control over the spatial arrangement of chromophores. However, it remains a challenge to precisely customize the positioning of chromophores in their aggregating form such as in a simplest cofacially stacked dimer. Herein, this work provides a customizable molecular design based on dissymmetrical ligands that can enable a precise control over chromophore interactions through the formation of metal-organic dimers. Anti-paralleled stacking of two dissymmetrical ligands in the metal-organic dimers results in a lateral shifting of chromophore stacking, whose spacing is determined and adjusted by the degree of ligand dissymmetry. Three metal-organic dimers with a variation in chromophore spacing exhibited unique photophysical properties in both solution and solid states and displayed high-efficient luminescence against quenching in their aggregating states. This strategy thereby offers a universally applicable way to construct chromophore dimers with fixed cofacial spacing and determinate through-space interactions.