Coordination polymers with embedded recognition sites: lessons from cyclotriveratrylene-type ligands

A review of coordination polymers formed using multi-topic cyclotriveratrylene-type ligands. Cyclotriveratrylene (CTV) is a molecular host with a bowl-shaped tribenzo[a,d,g]cyclononatriene scaffold. Tripodal and hexapodal ligands with N-donor and O-donor groups have been developed and these form a range of coordination chains, 2D and 3D coordination networks with transition metals. Such ligands are molecular hosts so there is potential to form materials with both host-specific and lattice guest-binding sites. This highlight article will discuss how the host–guest properties of the ligands can compromise the ability of CTV-type ligands to form such materials as intracavity guest binding, bowl-in-bowl stacking and hand-shake inclusion motifs effectively block the host-specific binding site. A range of coordination polymer materials which do feature hierarchical guest-binding sites are formed from CTV-type ligands, most commonly where there are networks of coordination capsules or cage, or where alternating bowl-up, bowl-down arrangements of ligands within networks leads to tubular structures.