Non-covalent interactions and reactivity of sulfur-rich birhodanine-based acceptors

A diverse library of π-conjugated electron acceptors is essential for the rational design of molecular materials with tunable electronic properties. In this context, the development of structurally related acceptors, including 3,3′-dialkyl-5,5′-bithiazolidinylidene-2,2′-dione-4,4′-dithiones ( OS- R ), their isomers 3,3′-dialkyl-5,5′-bithiazolidinylidene-4,4′-dione-2,2′-dithiones ( SO- R ), and their sulfur analogues 3,3′-dialkyl-5,5′-bithiazolidinylidene-2,4,2′,4′-tetrathiones ( SS- R ), with adjustable redox properties remains a key objective. In the present study, we focus on the intrinsic reactivity of these acceptor cores to deliberately tune their redox behavior. The resulting compounds were structurally characterized. Moreover, iodine atoms were incorporated into the acceptor framework to induce halogen bonding interactions, which were confirmed by X-ray diffraction analyses in both the synthetic precursors and the corresponding acceptors.