In this issue, you will find Reviews on activity-based NIR enzyme fluorescent probes for tumor diagnosis and surgery (J. Yoon et al.), self-reporting materials (C. Barner-Kowollik et al.), and pristine hollow metal–organic frameworks (R. Zou et al.). The Minireview by H. M. Chen et al. deals with the link between the dynamic chemical state of catalysts with the product profile of electrocatalytic CO₂ reduction.

In the original research section, D. Zhao et al. present tetrazole-functionalized zirconium metal-organic cages for efficient ethylene/acetylene and ethylene/CO₂ separations (see picture). E. M. Sletten et al. succeeded in the redox-responsive gene delivery from perfluorocarbon nanoemulsions through cleavable poly(2-oxazoline) surfactants. F. Beuerle et al. describe the isoreticular crystallization of highly porous cubic covalent organic cage compounds, and J. B. Goodenough et al. developed Li₂S₆-integrated PEO-based polymer electrolytes for all-solid-state lithium-metal batteries.

• Angewandte Chemie 32/2021: Dynamic States,
  Angew. Chem. Int. Ed. 2021, 60 (32).