Thermally activated delayed fluorescent (TADF) coordination polymer with the generation of singlet oxygen.

4,4'-{9,9'-Spirobi[10H-acridine]-10,10'-diyl}dibenzoic acid (L, C29H26N2O4) was designed and synthesized as a new donor-acceptor motif molecule. Due to the large dihedral angle between the planes of the carboxyphenyl group and the spiroacridine moiety, L possess thermally activated delayed fluorescence (TADF). By applying L as a ligand and using Cd as a metal connector, we synthesized the coordination polymer catena-poly[hemi-μ-aqua-aqua(μ3-4,4'-{9,9'-spirobi[10H-acridine]-10,10'-diyl}dibenzoato)cadmium(II)], [Cd(C29H24N2O4)(H2O)1.5]n, (I). X-ray crystallographic analysis revealed that this coordination polymer exhibits one-dimensional chains constructed from molecular twist-ring moieties, with Cd2O11 clusters as the connection nodes. The stacking pattern of the two-dimensional network was formed by C-H...π interactions in the solid state. Similar to L, (I) presents a sky-blue TADF emission, together with a photoluminescence quantum yield (PLQY) of 40%. It is worth noting that the photocatalytic activity toward the generation of singlet oxygen of this coordination polymer is confirmed.