Fig. 6. (a) Schematic representations of the two factors governing the breathing behaviour in 1: (b–d) rotation of the naphthalene rings (orange) relative to the plane between the four Zn ions (blue) and (e–g) kneecap hinge motion between planes passing through the ndc oxygen atoms (blue) and the Zn₂O₂ moiety (pink) of the SBU.