Bispalladium(II) Complexes of di‐<i>p</i>‐Pyrirubyrin Derivatives as Promising Near‐Infrared Photoacoustic Dyes
Karolina Hurej, Weronika Oszczęda, Ewelina Opas, Szymon J. Zelewski, Miłosz Pawlicki, Michał J. Białek, Łukasz Orzeł, Lechosław Latos‐Grażyński
Abstract
The insertion of palladium(II) into di-p-pyrirubyrin results in mutually convertible bimetallic complexes. Post-synthetic functionalization of one of them yielded bispalladium(II) dioxo-di-p-pyrirubyrin and, after demetallation, dioxo-di-p-pyrirubyrin, introducing for the first time the α,β'-pyridin-2-one unit into the macrocyclic frame. Bispalladium(II) di-p-pyrirubyrin 6, bispalladium(II) dioxo-di-p-pyrirubyrin 9, and dioxo-di-p-pyrirubyrin 10 absorb and emit light around 1000 nm and are characterized by high photostability. Thus, they are promising candidates for near-infrared photoacoustic dyes, ideally targeting (9) the wavelength of Yb-based fiber lasers. The incorporation of an α,β'-pyridine moiety into expanded porphyrins opens a highly interesting area of research due to the attractive optical and coordination properties of the resulting molecules.