Lanthanides in hydrogels, hybrid materials and clusters Seminar

The lanthanides are a fascinating group of elements that attract attention due to technological applications of their magnetic and photophysical properties. We are extending the coordination and structural chemistry of the lanthanides, to broaden the range of systems available for potential applications, and to develop fundamental understanding of lanthanide chemistry and materials.

This seminar will cover three vignettes of our research, with the common theme of lanthanide cations interacting with the macrocyclic calixarenes (see Figure). The first section will discuss hybrid materials that comprise of an organic polymeric framework that incorporates known calixarene ionophores. The material can be loaded post-­‐synthesis with the desired lanthanide cation, or mixture of cations, resulting in light-­‐emitting materials of any required colour.¹ Next, the synthesis and properties of a range of lanthanide clusters supported by new ligands will be described, including large “bottlebush” lanthanide clusters that form in the presence of a tetrazole-­‐functionalised calixarene (see Figure).² Finally, the behaviour of a calixarene hydrogelator triggered by the addition of lanthanide nitrates and other electrolytes will be covered.³ Under appropriate conditions, formation of reversible supramolecular hydrogels that are robust up to temperatures of 95 ˚C can be achieved. Our recent efforts to monitor the gel formation processes using variable temperature in situ scanning probe microscopy will be presented.

1. C.R. Driscoll, B.L. Reid, M.J. McIldowie, S. Muzzioli, G.L. Nealon, B.W. Skelton, S. Stagni, D.H. Brown, M. Massi, and M.I. Ogden, Chem. Commun., 47, 3876-­‐3878 (2011); B.W. Ennis, S. Muzzioli, B.L. Reid, D. D’Alessio, S. Stagni, D.H. Brown, M.I. Ogden and M. Massi, Dalton Trans., 42, 6894 -­‐ 6901, (2013).

2. D. D’Alessio, A.N. Sobolev, B.W. Skelton, R.O. Fuller, R.C. Woodward, N.A. Lengkeek, B.H. Fraser, M. Massi, M.I. Ogden, J. Am. Chem. Soc., 136, 15122-­‐5 (2014).

3. E.C. Barker, T. Becker, C.Y. Goh, F. Jones, M. Mocerino, B.W. Skelton and M.I. Ogden, Chem. Sci., 10.1039/C5SC02196K (2015).