New Conjugatable Platinum(II) Chlorins: Synthesis, Reactivity and Singlet Oxygen Generation.

An efficient protocol was developed for the microwave-mediated metallation of 5-(4-methoxycarbonylphenyl)-10,15,20-tris(pentafluorophenyl)porphyrin () with bis(benzonitrile)platinum dichloride salt and subsequent 1,3-dipolar cycloaddition of the resulting with an azomethine ylide to give two isomeric metallochlorins: (main isomer) and . The methyl ester group of metalloporphyrin and metallochlorin was successfully hydrolysed in an alkaline medium to yield the corresponding derivatives and in moderate-to-good yields. As a proof of concept of the reactivity of the carboxy group in and , these compounds were conjugated with a hydroxylated derivative of indomethacin, a known potent non-steroidal anti-inflammatory, obtaining the conjugates - and -. The obtained platinum(II) porphyrins and chlorins were characterized by UV-Vis, NMR spectroscopy and mass spectrometry. The structure of was also confirmed by X-ray crystallography. Singlet oxygen generation studies were carried out, as well as theoretical calculations, which demonstrated that the prepared Pt(II) complexes can be considered potential photosensitizers for PDT.