Prof. Roy Weinstain

School of Plant Sciences and Food Security

Tel Aviv University

Host: Dr. Art Winter

Roy Weinstain's Lab | Tel Aviv University

Abstract: From chromophores to photoremovable protecting groups – development and potential applications

Photoremovable protecting groups (PPGs, photocages) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical applications. Upon irradiation at a specific wavelength, PPGs are tracelessly removed, allowing for non-invasive spatio-temporal control over the release of molecules with a high degree of chemoselectivity in complex chemical and biological environments.

In recent years, we, and others, introduced and utilized meso-methyl BODIPY as a visible-light activatable PPG with tunable spectroscopic, chemical and biological properties for diverse applications in synthetic chemistry, biology and medicine.  

We then showed that porphyrin, a highly abundant chromophore, can be repurposed as a PPG by introducing a similar meso-methyl motif. Moreover, we showed that meso-methyl porphyrin is a prototype hybrid-class PPG that unites traditionally exclusive elements of organic and metal-complex PPGs within a single structure. We demonstrated that the porphyrin scaffold allows for extensive modularity four sites of leaving group release via functional separation of the metal-binding chromophore. The insertion of metal ions can be used to tune their spectroscopic and photochemical properties. This approach could facilitate access to a hitherto untapped chemical space of potential PPG scaffolds and utilizations in combined photodynamic and chemotherapy.

We are now applying photoremovable protecting groups, new and established, to applications in plant sciences and crop protection.