Year: 2026
Type: preprint
Abstract: Meltable coordination polymers (CPs) combine liquid-phase processability with the structural and functional diversity of crystalline coordination compounds, but methods to install targeted local coordination environments and photophysical functions in CP glasses remain limited. Here, we demonstrate that 1,10-phenanthroline (phen) reacts with the 1D-extended Cu I -CP Cu(ipim) (Cuip; ipim − = 2-isopropylimidazolate) in the melt, converting half of the linearly coordinated Cu I sites into pseudo-tetrahedral [Cu(phen)(ipim) 2 ] − units while preserving chain topology and the interchain-separation melting mechanism. Depending on thermal history, the resulting phen 0.5 Cuip forms either a melt-quenched glass or crystalline polymorphs, whereas pristine Cuip invariably recrystallizes on cooling. X-ray total scattering and spectroscopic analyses show that the local Cu I -phen motif is retained across the phases, while the coordination geometry, interchain order, and phen···phen π-stacking interactions differ. Ligand addition transforms the photophysics from green phosphorescence in Cuip to broad near-infrared emission centered at approximately 850 nm in both crystalline and glassy phen 0.5 Cuip. The pronounced temperature dependence of this emission is consistent with a thermally activated delayed fluorescence mechanism. Calculations indicate that the extended CP environment restricts flattening of the pseudo-tetrahedral [Cu(phen)(ipim) 2 ] − units after metal-to-ligand charge-transfer (MLCT) excitation, thereby limiting access to non-radiative decay pathways. Melt-state ligand addition thus provides a route to construct molecular-complex-like functional units during processing, linking reactive CP melt chemistry to targeted photophysical design in CP glasses.
Source: ChemRxiv
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7212119226