Bioorthogonal Phosphorogenic Rhenium(I) Polypyridine Sydnone Complexes for Specific Lysosome Labeling

Abstract Invited for this month's cover is the group of Prof. Kenneth Kam‐Wing Lo at City University of Hong Kong, Hong Kong, P. R. China. The cover picture shows the selective landing of a bioorthogonal spacecraft on a lysosomal planet modified with a strained cyclooctyne moiety in an intracellular environment with other organelles and a plethora of biomolecules. A sydnone moiety is appended to a luminescent rhenium(I) diimine unit as both an emission quencher and a bioorthogonal handle. Selective strain‐promoted sydnone–alkyne cycloaddition (SPSAC) of the complex with a strained alkyne leads to impressive emission turn‐on, which can be exploited in bioimaging and phototherapeutic applications. Read the full text of the article at 10.1002/cplu.202000029 .