Dispersion Stabilized Se/Te•••π Double Chalcogen Bonding Synthons in in Situ Cryocrystallized Divalent Organochalcogen Liquids

We report the experimental observation and detailed quantum chemical analysis of the rare bifurcated type Se center dot center dot center dot pi and Te center dot center dot center dot pi double chalcogen bonded synthons observed through the in situ cryocrystallization of two room temperature organochalcogen liquids, namely, diphenylselenide and diphenyl telluride. The attractive intermolecular interactions between the heavier chalcogens and pi-clouds are primarily stabilized by the dispersion forces, which is in contrast to many known model examples in the literature. Electrostatic and orbital delocalization effects also play a secondary but important role in the overall stabilization, besides providing directionality to these interactions.