Ligand release from silicon phthalocyanine dyes triggered by X-ray irradiation. Issue 36 (16th August 2022)

• Record Type: Journal Article
• Authors: Takakura, Hideo; Matsuhiro, Shino; Inanami, Osamu; Kobayashi, Masato; Saita, Kenichiro; Yamashita, Masaki; Nakajima, Kohei; Suzuki, Motofumi; Miyamoto, Naoki; Taketsugu, Tetsuya; Ogawa, Mikako
• Is Part Of: Organic & biomolecular chemistry. Volume 20:Issue 36(2022)
• Page Start: 7270
• Page End: 7277
• Publication Date: 2022-08-16
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/d2ob00957a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : We demonstrate the X-ray-induced axial ligand cleavage of silicon phthalocyanines via a radical chain reaction. Abstract : Ligand release from silicon phthalocyanine (SiPc) dyes triggered by near-infrared (NIR) light is a key photochemical reaction involving caged compounds based on SiPc. Although NIR light is relatively permeable compared with visible light, this light can be attenuated by tissue absorption and scattering; therefore, using light to induce photochemical reactions deep inside the body is difficult. Herein, because X-rays are highly permeable and can produce radicals through the radiolysis of water, we investigated whether the axial ligands of SiPcs can be cleaved using X-ray irradiation. SiPcs with different axial ligands (alkoxy, siloxy, oxycarbonyl, and phenoxy groups) were irradiated with X-rays under hypoxic conditions. We found that the axial ligands were cleaved via reactions with hydrated electrons (e − aq ), not OH radicals, generated from water in response to X-ray irradiation, and SiPc with alkoxy groups exhibited the highest cleavage efficiency. A quantitative investigation revealed that X-ray-induced axial ligand cleavage proceeds via a radical chain reaction. The reaction is expected to be applicable to the molecular design of X-ray-activatable functional molecules in the future.