Exploiting 2-(alkylsulfonyl)pyridines as 1,3-N,S-ligands, herein we have constructed 1D CuI-based coordination polymers (CPs) bearing unprecedented (CuI)_n chains and possessing remarkable photophysical properties. At room temperature, these CPs show efficient TADF, phosphorescence or dual emission in the deep-blue to red range with outstandingly short decay times of 0.4–2.0 μs and good quantum performance. Owing to great structural diversity, the CPs demonstrate a variety of emissive mechanisms, spanning from TADF of ¹(M + X)LCT type to ³CC and ³(M + X)LCT phosphorescence. Moreover, the designed compounds emit strong X-ray radioluminescence with the quantum efficiency of up to an impressive 55% relative to all-inorganic BGO scintillators. The presented findings push the boundaries in designing TADF and triplet emitters with very short decay times.

An efficient and chemoselective mechanochemical synthesis of a bright TADF-emitting CuI-based compound is reported. The reaction of 2-(ethylsulfanyl)-6-methylpyridine (L) with CuI under solvent-free conditions or in solution results in a non-emissive complex, [Cu₂I₂L₂] (1) or a 1-D coordination polymer (CP), [Cu₃I₃L₂]_n (CP 2), respectively. Meanwhile, the simple manual grinding of the reactants in the presence of a few drops of MeCN for 1–2 min chemoselectively gives the structurally different 1-D CP, [Cu₃I₃L₂]_n (CP 3), as a single product isolated in 87% yield. Remarkably, both complex 1 and CP 2 under the mechanochemical conditions easily (1–2 min) undergo polymerization or isomerisation, accordingly, to afford CP 3. The structure of the latter is formed by cuprophilic interaction-free (–Cu–I–)_n chains ligated by 2-(ethylsulfanyl)-6-methylpyridines in a μ₂-N,S manner. At room temperature, CP 1 exhibits highly efficient blue-green TADF with a short lifetime (4.0 μs) and a high photoluminescence performance (PLQY being 70%).

Problems of computationally feasible quantum chemistry methods in reproducing the short experimental gas-phase non-covalent Si ← N contacts (d_SiN < 2.3 Å) in the geminal fragments (SiNN and SiON) of silicon-containing compounds.