The cover picture shows a guanidine–quinoline–copper complex as a new entatic-state model. Small changes in the ligand strongly affect the molecular structure, which demonstrates the subtle balance of steric and electronic effects at a metal center. The unique combination of solid-state and solution structural investigations by classical single-crystal X-ray diffraction and X-ray absorption spectroscopy together with density functional theory reveals deep insights into this entatic-state model. Details are discussed in the article by S. Herres-Pawlis et al. on
p. 4731 ff. For more on the story behind the cover research, see the
Cover Profile.