Enhancement of molecular conductance through a supramolecular five-molecule assembly

Achieving a comprehensive understanding and precise control of non-covalent interactions is crucial in molecular design and the development of functional molecular electronic devices, where supramolecular interactions enable the control of the local environment in molecular assemblies. Here, intermolecular interactions are used to create a complex supramolecular assembly by π stacking of 1,1′-bis(4-(methylthio)-phenyl)-[4,4′-bipyridine]-1,1′-diium chloride (1[Cl]2) and tetracyanoquinodimethane radical anion (TCNQ·−), whose crystal structure is determined by an electron diffraction technique, showing the presence of stacked 12+-2(TCNQ·−) units. This solid dissolves in aqueous solutions of cucurbit[8]uril (CB[8]), which acts as the host, to form a supramolecular five-molecule {12+-2(TCNQ·−)@2CB[8]} assembly. Its transport properties result in a significant enhancement of conductance. Theoretical studies confirm the stability of the supramolecular assembly and corroborate the enhancement in conductance. These results present a simple and effective method for stabilizing and enhancing charge transport efficiency through a combination of non-covalent and supramolecular interactions, with significant implications for the development of future (opto)electronic devices.