Design of porphyrin-based conjugated microporous polymers with enhanced singlet oxygen productivity

Abstract

Novel non-toxic materials with antimicrobial surfaces are needed for medicinal applications. Potential alternatives for bacterial inactivation include materials that produce singlet oxygen, O₂(¹Δ_g), a short-lived, highly oxidative, and cytotoxic species. We synthesized a promising group of materials, porphyrin-based conjugated microporous polymers (CMPs), which effectively generate O₂(¹Δ_g) under visible light irradiation. CMPs were rationally designed and synthesized to maximize O₂(¹Δ_g) production. A strategy based on three-dimensional frameworks allowed the immediate environment of the porphyrin units to be tuned and their structure–property relationships to be elucidated. We investigated the photophysical and photochemical properties of the frameworks and compared them with the properties of porphyrin-based CMPs and metal–organic frameworks. In general, the O₂(¹Δ_g) production activity of the CMPs correlated with neither the surface area nor with the pore volume. The novel CMPs displayed high O₂(¹Δ_g) production, were stable in organic solvents, and did not undergo measurable photobleaching.