Supramolecular Tessellations by a Rigid Naphthalene Diimide Triangle.

Tessellation of organic polygons though [π···π] and charge-transfer (CT) interactions offers a unique opportunity to construct supramolecular organic electronic materials with 2D topologies. Our approach to exploring the 3D topology of 2D tessellations of a naphthalene diimide-based molecular triangle () reveals that the 2D molecular arrangement is sensitive to the identity of the solvent and solute concentrations. Utilization of nonhalogenated solvents, combined with careful tailoring of the concentrations, results in self-assembling though [π···π] interactions into 2D honeycomb triangular and hexagonal tiling patterns. Cocrystallization of with tetrathiafulvalene () leads systematically to the formation of 2D tessellations as a result of superstructure-directing CT interactions. Different solvents lead to different packing arrangements. Using MeCN, CHCl, and CHCl, we identified three sets of cocrystals, namely , , and , respectively. Solvent modulation plays a critical role in controlling not only the : stoichiometric ratios and the molecular arrangements in the crystal superstructures, but also prevents the inclusion of guests inside the cavities of . Confinement of inside the cavities in the superstructure enhances the CT character with the observation of a broad absorption band in the NIR region. In the superstructure, the CHCl lattice molecules establish a set of [Cl···Cl] and [Cl···S] intermolecular interactions, leading to the formation of a hexagonal grid of solvent in which forms a triangular grid. In the superstructure, three molecules self-assemble, forming a supramolecular isosceles triangle , which tiles in a plane alongside the , producing a 3 + 3 honeycomb tiling pattern of the two different polygons. Solid-state spectroscopic investigations on revealed the existence of an absorption band at 2500 nm, which on the basis of TDDFT calculations, was attributed to the mixed-valence character between two radical cations and one neutral molecule.