BSc, 1964, University of Edinburgh; PhD, 1966, University of Edinburgh; DSc, 1980, University of Edinburgh.
The chemistry of (i) large molecular species and (ii) aggregates of small molecular entities comprise the main research activities that are pursued within a multinational team of postdoctoral research fellows and postgradute students.
Based on the belief that functions of a machine-like nature can ultimately be realised by molecular components moving and interacting on a scale of tens of Ångstroms -- that is, on the so-called nanoscale -- chemistry of a modular nature is being developed that depends, not only on synthesising compounds at a molecular level by the making and breaking of covalent bonds often in the presence of protecting groups, but also appeals to the much weaker noncovalent bonding interactions that exist between ions and/or molecules that are steroelectronic matches and so recognise each other to form highly ordered complexes in solution and in the gas phase, as well as in the solid state. This contemporary chemistry which is executed beyond the molecule -- and is often referred to as supramolecular chemistry -- can be harnessed in an increasingly predictable manner to build up arrays of molecules. Noncovalent bonding interactions can also be employed cooperatively during synthesis to template reactions in a manner that is reminiscent of the ways in which biological systems undergo self-assembly.
Indeed, the transfer of concepts like self-assembly, from biology into chemistry, is one of the fundamentally new ways of approaching chemical synthesis that is now being developed and exploited within the Stoddart group. This new approach to synthesis that depends on recognition between preprogrammed building blocks has led to the construction of a wide range of mechanically-interlocked molecular compounds in the form of the so-called catenanes and rotaxanes. Catenanes are comprised of two or more interlocking ring components. Rotaxanes are comprised of one or more ring components located on a dumbbell-shaped component. The noncovalent bonding interactions that allow such exotic molecular compounds to be formed efficiently 'live on' inside the molecules giving them low and high energy states that form the basis of mechanical switching and shuttling processes between the "intelligent" components. Numerous ways are being explored that allow these little molecular machines to be driven by the addition or subtraction of electrons, protons, or photons. Efforts are also being directed into lining up these individual machine-like molecules in an organised manner at interfaces and surfaces so that they might act in a coherent manner at a macroscopic level.
The buiding blocks are both 'natural' and 'unnatural'. The chemistry sometimes involves carbohydrates, other times heterocycles, both saturated and unsaturated. The macromolecular systems range from snake-like to tree-like. The noncovalent bonding interactions employed in the recognition processes include hydrogen bonds and stacking interactions between aromatic rings. The chemistry is intellectually-challenging and highly fundamental. The result is artistic. The mission and vision are futuristic.
Selected Recent Publications
(1) A chemically and electrochemically switchable molecular device
R.A. Bissell, E. Códova, A.E. Kaifer, J.F. Stoddart, Nature, 369, 133 (1994).
(2) Olympiadane
D.B. Amabilino, P.R. Ashton, A.S. Reder, N. Spencer, J.F. Stoddart, Agnew. Chem., Int. Ed. Engl., 33, 1286 (1994).
(3) Catenated cyclodextrins
D. Armspach, P.R. Ashton, R. Ballardini, V. Balzani, A. Godi, C.P. Moore, L. Prodi, N. Spencer, J.F. Stoddart, M.S. Tolley, T.J. Wear, D.J. Williams, Chem. Eur. J., 1, 33, (1995).
(4) Molecular mosaics formed by a square cyclophane and its inclusion complex with ferrocene
P.R. Ashton, C.G. Claessens, W. Hayes, S. Menzer, J.F. Stoddart, A.J.P. White, D.J. Williams, Agnew.Chem., Int. Ed. Engl., 34, 1862 (1995).
(5) Dialkylammonium ion/crown ether complexes: the forerunners of a new family of interlocked molecules
P.R. Ashton, P.J. Campbell, E.J.T. Chrystal, P.T. Glink, S. Menzer, D. Philip, N. Spencer, J.F. Stoddart, P.A. Tasker, D.J. Williams, Agnew. Chem., Int. Ed. Engl., 34, 1865 (1995).