Ternary π–π Stacking Complexes by Allosteric Regulation in Multilayer Nanographenes

Additional data to report https://doi.org/10.1021/jacs.4c11119:

Construction of π–π stacking supramolecular complexes with more than two components is challenging due to the weak and directionless nature of dispersion interactions. Here we report ternary complexes of a ditopic nanographene tetraimide (1), α-substituted phthalocyanine (Pc) and polyaromatic hydrocarbons (PAHs) in solution and crystalline state via allosteric regulation. Binding of one Pc give rise to significant distortion and conformational changes in 1 that in turn lead to the inhibition of the second binding of Pc. The conformational changes associated with first binding allowed an allosteric binding of a third component (PAHs) to form ternary complexes in solution. 1H NMR titration revealed a moderately high thermodynamic stability for the ternary complexes in CDCl3. Competition between allosterically regulated ternary complexes ([Pc·1·PAH]) and 1:2 stoichiometric binary complexes of 1 with PAHs ([PAH·1·PAH]) were elucidated. Further, selective formation of ternary complexes in solution led to the generation of ternary cocrystals from a 1:1:1 mixture of three components in solution. Our work shows that large π-conjugated nanographenes designed with allosteric recognition sites allow the construction of multilayer ternary complexes in solution and solid-state even with dispersive π–π interactions.