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Department of Chemistry

Prof. Jonathan W. Steed

Personal web page

Professor in the Department of Chemistry
Telephone: +44 (0) 191 33 42085
Member of the Durham X-ray Centre

(email at jon.steed@durham.ac.uk)

Biography

Jonathan W. Steed was born in London, UK in 1969. He obtained his B.Sc. and Ph.D. degrees at University College London, working with Derek Tocher on organometallic and coordination chemistry. He graduated in 1993 winning the Ramsay Medal for his Ph.D. work. Between 1993 and 1995 he was a NATO postdoctoral fellow at the University of Alabama and University of Missouri, working with Jerry Atwood. In 1995 he was appointed as a Lecturer at King's College London. In 2004 he joined Durham University where he is currently Professor of Inorganic Chemistry. Professor Steed is co-author of the textbooks Supramolecular Chemistry (2000 & 2009) Core Concepts in Supramolecular Chemistry and Nanochemistry (2007) and around 300 research papers. He has edited the Encyclopaedia of Supramolecular Chemistry (2004), Organic Nanostructures (2008) and the 8-volume Supramolecular Chemistry from Molecules to Nanomaterials (2012). He is the recipient of the RSC Meldola Medal (1998), Durham's Vice Chancellor's Award for Excellence in Postgraduate Teaching (2006), the Bob Hay Lectureship (2008) and the RSC Corday-Morgan Prize (2010). His interests are in anion binding and sensing, supramolecular gels and crystalline solids particularly pharmaceutical solids, co-crystals and hydrates. See personal web pages for full details.

Supramolecular Chemistry

Traditional molecular chemistry is largely concerned with the synthesis and study of molecules linked by covalent bonds between atoms. However, there is another entire area of chemistry, often impinging on nanometre scale assemblies, that transcends the chemistry of the covalent bond. This is termed Supramolecular Chemistry and it involves the study of systems bonded by a multitude of non-covalent interactions, particularly hydrogen bonding, π-π stacking, and metal-ligand dative bonds. Many of these kinds of interactions are difficult to control yet their importance and potential is mind blowing. For example, in biochemistry Nature relies heavily on just these interactions to fold proteins into their active conformations and, crucially, it is hydrogen bonding (base pairing) and π-π stacking that give DNA its characteristic double helical shape. Prof. Steed is the author of a definitive book on Supramolecular Chemistry.1

Molecular Sensors

Our work encompasses many aspects of supramolecular chemistry from crystallization and the nature of individual interactions (particularly in the solid state) to their incorporation and use in functioning molecular devices, particularly in applications such as the design and synthesis of molecular sensors for anions (e.g. environmental pollutants). To take just one example, a complex molecular device based on a calixarene (shown on the right) is capable of selectively recognising and binding a two halide anions entirely through non-covalent interactions (NH···X and CH···X hydrogen bonds) and photochemically signalling that binding via the appended pyrene units.2

Supramolecular Gels

Gels comprise a liquid trapped by a highly porous network of nanometre-scale fibres. As well as being fascinating because of their complex and emergent microstructure, the highly porous, locally ordered network in gels, coupled with their formation by spontaneous self-organization gives them tremendous technological possibilities, for example in the controlled formation of highly porous polymers and in the controlled crystallization of targeted pharmaceutical polymorphic forms, an area of particular interest for our group.5 Extremely simple, readily prepared bis(urea) building blocks give gels via a hierarchical series of self-organization steps strongly influenced (both positively and negatively) by ionic additives such as metal salts. The intrinsic ability of bis(ureas) to aggregate via NH∙∙∙O=C hydrogen bonded interactions is modulated and can be switched on and of by reversible coordination interactions to metal cations and hydrogen bonding to conjugate anions. Our group are particularly active in the design of targeted gels for pharmaceutical crystal form control. An SEM image of a dried gel showing chiral helical fibres derived from a chiral gelator is shown left.3-7

Crystallography and Solid Form

Facilities at Durham for both single crystal and powder work are internationally leading. The group is also particularly active in structure determination by neutron diffraction and students have the opportunity of taking part in visits to facilities at the ILL in Grenoble, France or the ISIS facility in the UK. Our single crystal neutron structure of the exotic H7O3+ ion trapped by two molecules called 'crown ethers' is shown right. We are particularly interested in low symmetry crystal structures with more than one molecule in the asymmetric unit7 and we maintain a dedicated web resource on this work (http://zprime.co.uk). The group are also expert in the study of polymorphism, particularly in pharmaceutical hydrates and in the use of novel methods such as gel phase crystal growth and mechanochemistry to influence solid form.

References

  1. J. W. Steed and J. L. Atwood, "Supramolecular Chemistry", 2nd Ed, J. Wiley & Sons: Chichester, 2009.
  2. “Induced Fit Inter-Anion Discrimination by Binding-Induced Excimer Formation”, M. H. Filby, S. J. Dickson, N. Zaccheroni, L. Prodi, S. Bonacchi, M. Montalti, M. J. Paterson, T. D. Humphries, C. Chiorboli, and J. W. Steed, J. Am. Chem. Soc., 2008, 130, 4105-4113.
  3. "Anion-Tuning of Supramolecular Gel Properties", G. O. Lloyd and J. W. Steed, Nature Chem., 2009, 1, 437.
  4. "Metal- and Anion Binding Supramolecular Gels", M. M. Piepenbrock, G. O. Lloyd, N. Clarke and J. W. Steed, Chem. Rev., 2010, 110, 1960.
  5. "Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth”, J. A. Foster, M.-O. M. Piepenbrock, G. O. Lloyd, N. Clarke, J. A. K. Howard and J. W. Steed, Nature Chem., 2010, 2, 1037–1043.
  6. “Halogen-Bonding-Triggered Supramolecular Gel Formation”, L. Meazza, J. A. Foster, K. Fucke, P. Metrangolo, G. Resnati and J. W. Steed, Nature Chem., 2013, 5, 42–47.
  7. “Blending gelators to tune gel properties and probe anion-induced disassembly”, J. A. Foster, R. M. Edkins, G. J. Cameron, N. Colgin, K. Fucke, S. Ridgeway, A. G. Crawford, T. B. Marder, A. Beeby, S. L. Cobb and J. W. Steed, Chem. Eur. J., 2014, 20, 279–291.
  8. “Packing Problems: High Z′ Crystal Structures and their Relationship to Cocrystals, Inclusion Compounds and Polymorphism,” K. M. Steed and J. W. Steed, Chem. Rev. 2015, doi: 10.1021/cr500564z.

Selected Publications

Journal Article

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