Building coordination polymers with host ligands
- Date: Wednesday 18 November 2020, 09:00 – 10:30
- Location: Online event
- Type: Seminars, Chemistry
- Cost: Free
Professor Michaele Hardie will be presenting the online seminar organised by the RSC Porous Materials Interest Group.
Title: Building coordination polymers with host ligands
Molecular hosts are cyclic molecules with clearly defined molecular cavities that can bind guest species in a non-covalent manner. Hosts such as cyclodextrins and calixarenes can be used as ligand components of crystalline coordination polymers/MOFs. Our work involves the use of cyclotriveratrylene (CTV) analogues which have been functionalised with metal binding groups. These can assembly with transition metals into discrete cage structures or into chain, 2D or 3D coordination polymer materials. The advantage of using molecular hosts as ligands for coordination polymers is that they have intrinsic guest binding properties, hence hierarchical spaces within a framework may be created – namely lattice-type pores and the specific inclusion sites of the host. However the ability of these molecules to form host-guest interactions can also trip-up our designs. CTV-analogues have a tendency to form self-inclusion motifs and if these translate into a coordination polymer then their site-specific binding cavities are effectively blocked. This can be overcome by formation of linked cage motifs within a coordination polymer. A spectacular example is the Cu(II)-coordination polymer of Cu3L2-cages linked into a 2D network, a material that can uptake fullerene-C60 from solution. Interestingly, host-guest interactions between complexes have been identified as a factor on the formation of the Borromean chain-mail structure. This is a topologically unique entangled structure where 2D arrays of discrete Cu6L6 metalla-macrocycles are entangled through multiple Borromean ring associations.