Subtle C–H···Hal (Hal = Cl, Br) Bonding as Predominant Synthon in the Assembly of Supramolecular Architectures Based on Luminescent Tin(IV) Complexes. Crystallography, Hirshfeld Surfaces, DFT Calculations, and Fluorescence

This report illustrates a successful C–H···Hal synthon-directed strategy to promote supramolecular aggregation of molecular luminescent complexes 1–6 into two- or three-dimensional supramolecular architectures. The tin complexes were prepared from the reaction of RnSnHal4–n compounds (R = n-Bu, Ph; Hal = Cl, Br; n = 0, 1) with (C5H4N)­HCN­(C6H4)­EH Schiff bases by either step-by-step synthesis [E = O (PyNO)] or multicomponent reaction [E = S (PyNS)]. Compounds 1–6 were characterized by IR, Raman, and 1H, 13C, and 119Sn NMR spectroscopic studies as well as by X-ray diffraction studies. In addition, the fluorescent properties of all compounds were also investigated in the solid state and in THF solutions; the emission wavelengths ranged from orange to red (λmax = 591–626 nm). Detailed structural characterization of the supramolecular organization of ordered solids revealed overall 2D and 3D interlinked networks driven by extensive C–H···Hal–Sn (Hal = Cl, Br) weak hydrogen bonds as primordial synthon and further stabilized by π···π stacking interactions as well as C–H···π, C–H···O, or C–H···N contacts. Hirshfeld surface analysis and DFT calculations were used to asses additional insights into crystal structural features.