SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3653-2
Designing photosensitizers with efficient intersystem crossing (ISC) and long-lived triplet excited states is critical for photodynamic therapy (PDT). However, conventional molecular design principles often rely on heavy-atom effects or specific donor-acceptor architectures, limiting generality. Here, we report a facile and rational strategy to convert intrinsically non-photosensitizing fluorophores into effective reactive oxygen species (ROS) generators by introducing guanidinium substituents. The modified photosensitizers exhibit prolonged triplet excited state lifetimes and considerable ROS production, in stark contrast to unmodified fluorophores which show intense fluorescence and negligible ROS generation. Electron paramagnetic resonance spectroscopy and high-resolution mass spectrometry confirm the formation of stable nitrogen-centered radical cations on the guanidinium moiety, stabilized by p-π conjugation. Mechanistic studies indicate that these radicals promote ISC and prolong triplet state lifetimes. In vitro and in vivo experiments demonstrate that guanidinium-modified photosensitizers induce immunogenic cell death (ICD) and elicit potent anti-tumor immunity. This work provides a universal and facile strategy for designing organic photosensitizers through stable radical cation-containing building blocks, expanding the scope of PDT agents.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4046-6
The deliberate control of framework dimensionality represents a powerful yet underexplored strategy for tailoring the functionality of homochiral metal-organic frameworks (HMOFs). Herein, we report a logical dimensional evolution from 1D and 2D to 3D HMOFs, achieved by tuning the connectivity of the auxiliary ligand. Employing a planar, three-connected ligand, 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (Tpt), together with enantiopure tetracarboxylate of cyclohexane diamide linkers ((1R,2R/1S,2S)-cyclohexane-1,2-dicarbonyl bis(azanediyl)diisophthalate) (R,R/S,S-CHCAIP) and Zn2+ salts, a pair of 3D porous HMOFs (P/M-HMOF-5) was successfully constructed. The 3D framework features unique heart-shaped channels and a novel 4-(3,3,3,6)-connected topology. Structural analyses reveal trinuclear Zn3(μ3-O) clusters that, upon activation, generate open metal sites. These Lewis acid sites, synergizing with Lewis basic sites from the framework, confer efficient acid-base bifunctional heterogeneous catalysis for the synthesis of 2,3-dihydroquinazolinones in excellent yields (90%–98%). Furthermore, P/M-HMOF-5 serve as highly sensitive and enantioselective fluorescent sensors for amino acids and α-hydroxy carboxylic acids, with the highest discrimination observed for phenylalanine (KBH(D-Phe)/KBH(L-Phe) = 5.85 for M-HMOF-5). This work demonstrates how rational ligand connectivity steers dimensional evolution, enabling the integration of distinct catalytic and sensing functions within a single chiral platform, thereby providing a blueprint for the design of advanced multifunctional materials.