Unprecedented 3D polycatenation based on ribbons of rings found in two metallosupramolecular polymers whose open frameworks show reversible collapse upon de- and rehydration

Two isostructural metallosupramolecular polymers [M(H2O)4–(BCbpy)2]2Cl4·18H2O [M = Co(II), Ni(II); HBCbpyCl = 1-(4-carboxybenzyl)-4,4′-bipyridinium chloride] have been synthesized by the self-assembly reaction of HBCbpyCl salt with MCl2 (M = Co, Ni). The unprecedented catenation of the (1D → 3D) type based on ribbons of rings is found in both supramolecular networks. Interestingly, this catenation mode can help generate channels, and the resulting supramolecular frameworks show recoverable collapse upon de- and rehydration, making them good potential adsorbents of water vapor.