Cyclometallated Iridium(III) Complex with Benzothiophenylpyridyl and Norbornene-Substituted Picolinate Ligands and Related Water-Soluble Polymer: Synthesis and Photophysical and Biological Properties

A new iridium(III) complex with cyclometallating benzothiophenylpyridyl ligands and an additional norbornene-substituted picolinate ligand NBEpicIr(Btp)2 (I) (NBEpicH is 3-(((1S,4S)-bicyclo[2.2.1]hept-5-ene-2-carbonyl)oxy)picolinic acid, and BtpH is benzothiophenylpyridine) is synthesized. The structures of the iridium-containing reagents (Btp)2IrCl(DMSO-d6) (II) and (Btp)2IrCl(DMSO) (III) are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2456556 and 2456557, respectively). Polymer sensor P1 is synthesized from norbornene-containing iridium complex I using metathesis polymerization. Polymer sensor P1 has a low cytotoxicity, penetrates into tumor cells, and can be used for measuring oxygen content in tumors.