Supramolecular 3D Polymers Created via Chalcogen Bonding Using Benzotellurazoles as Planar Recognition Units

In addition to hydrogen and halogen bonds, chalcogen bonds (ChBs) are gaining significance in the domain of crystal engineering. Nitrogen-containing tellurium compounds are well-suited for this purpose, as they form a variety of solid-state structures through ChBs. Despite prior studies addressing substituent effects in benzotellurazoles, the influence of fluorine atoms on the benzene backbone of 1,3-benzotellurazoles remains to be investigated in the context of solid-state arrangement. Here, we demonstrate that the incorporation of fluorine atoms can impact the nature and quantity of ChBs in the solid state. The electron-withdrawing properties of the introduced substituents result in alterations to the ChB donor (Te) and acceptor (N) properties, leading to a preferential interaction with competing Lewis bases such as carbonyl groups. A noteworthy exception was noticed for the derivatives with a nitrile group at position 2. Regardless of the number of fluorine atoms, a high degree of 3D cross-linking can be observed via a 5-ChBs-5-neighbors motif, including a characteristic two-lone-pair/one-σ-hole interaction. These findings offer valuable design principles for supramolecular materials, particularly in the context of crystal engineering.