Project

Polymers; Networks; Photoactive; Metals; Ligands;

Lead
Lay summary
In the first part of the project, we will synthesize a range of molecules (so-called divergent ligands) capable of binding metal ions thereby forming 1-dimensional chains or 2-dimensional or 3-dimensional networks. The  divergent ligands will fall into two families: (i) monotopic ligands containing pendant chromophores, and (ii) ditopic ligands in which the metal-binding domains are connected in a back-to-back fashion. The absorption and emission properties of the ligands will be studied, and structure-property relationships developed. Once the properties of these molecules are fully understood, we will investigate their metal ion-binding properties and their ability to direct the formation of coordination polymers and networks. We aim to produce a wide range of photoactive polymers. One of the properties that the networks are designed to possess is vacant Lewis base sites, i.e. sites that are sensitive to the presence of acids. The behaviour of the solid state materials towards protons and other Lewis acids will be explored and use of the polymers as sensors examined.

Direct link to Lay Summary

Last update: 21.02.2013

Number	Title	Start	Funding scheme

The project capitalizes on our recent preliminary investigations of thecoordination chemistry of 4,2':6',4"-terpyridines. Surprisingly, this is a little explored field, despite the fact that the ligands are readily prepared and provide building blocks that pack efficiently in the solid state through face-to-face p-interactions. 4,2':6',4"-Terpyridine differs from the well-established 2,2':6',2"-terpyridine in offering a divergent N,N'-donor set rather than a chelating N,N',N''-domain. In known metal complexes of 4,2':6',4"-terpyridines, the central pyridine ring remains non-coordinated.We will synthesize a suite of back-to-back 4,2':6',4"-terpyridines: directly linked through the 4'-positions, linked through conjugated p-systems, or linked through trans-platinum(II) units. A second family of monotopic ligands containing pendant chromophores will also be prepared.Full characterization of the new ligands will include their solution and solid state absorption and emission properties, attention being paid to correlations between structure and perturbation of ?em.The extended p-systems present in these compounds will aid the crystallization both of the free ligands and of coordination polymers. We will initially focus on complexes containing Zn(II), Cd(II) and Ag(I). Structural characterization of polymeric materials via single crystal X-raydiffraction and measurements of the solid state absorption and emission spectra will be essential parts of the project, with observed structure-property trends fed back into the project to aid further ligand design. An attractive feature of coordinated 4,2':6',4"-terpyridines is the presence of anchored Lewis base sites, and the behaviour of the solid state materials assensors for protons and other Lewis acids will be assessed.