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.