Perfluoroaromatic Selenoxides: Synthesis, Crystal Engineering via Se···O/Se···N Chalcogen Bonding, and Theoretical Analysis

Chalcogen-bonded (ChB) synthons have become essential tools for crystal engineering and supramolecular chemistry. This work explores perfluoroarylselenoxide (Ar2FSe═O) moieties as a promising class of ChB donors. We report a general synthetic route to these compounds via oxidation of perfluoroarylselenides with fuming nitric acid, affording high yields with minimal byproducts. Single-crystal X-ray diffraction analysis demonstrates that these perfluoroarylselenoxides self-associate via robust intermolecular Se···O interactions to form dimeric or tetrameric assemblies. Comprehensive DFT calculations, including Molecular Electrostatic Potential surface analysis, confirm that oxidation significantly enhances the electrophilic σ-holes at the selenium center compared to those of their selenide precursors. The dual functionality of these tectons is further highlighted in cocrystals with bipyridine linkers, where the selenium atom simultaneously engages multiple σ-holes through concurrent Se···N and Se···O interactions. Topological characterization using QTAIM and NCIplot, alongside Energy Decomposition Analysis and Natural Bond Orbital calculations, quantifies the substantial stabilization energies and orbital charge-transfer effects (LP(N/O) → σ*(Se–C)) that drive these architectures. These findings establish perfluoroarylselenoxides as versatile, highly effective, and directional tectons for the design of complex supramolecular materials.