LAUSR

Studies on a series of tetracyanoquinodimethanes (TCNQs) fused with [1,2,5]chalcogenadiazole rings revealed that chalcogen bonds (ChB) through E ••• N≡C (E = S or Se) contacts are a decisive factor in determining their crystal structures, with the formation of one- or two-dimensional networks in a lateral direction. For anion-radical salts generated by one-electron reduction, electron conduction occurs in the direction of the network due to intermolecular electronic interaction by ChB. Based on the reliable synthon of E ••• N≡C for crystal engineering, molecular recognition occurs so that solid-state molecular complexes are selectively formed with certain donors, such as xylenes, among their isomers by charge-transfer-type clathrate formation. The inclusion cavity of the clathrate could provide a reaction environment for photoinduced electron-transfer in the solid state. The accommodation of multiple conformers of overcrowded ethylene exhibiting thermo/mechanochromism is another example of the novel functions that can be realized by ChB through E ••• N≡C contacts. Therefore, these chalcogenadiazolo-TCNQs endowed with the ability to form ChB are promising materials for the development of novel solid-state functions.