 Professor
H.L. Anderson
Chemistry Research Laboratory
Telephone: 44 (0) 1865 275704
Current Research Projects - Molecular Engineering
We design and synthesise new molecular materials, and explore how their properties
relate to their molecular structures. This is "molecular engineering" – engineering
at the nano-scale. We particularly like using non-covalent self-assembly to control
the behaviour of organic semiconductors and dyes, for diverse applications. Our
main technique is synthesis, but we also do many other types of experiments,
from biological testing to solid-state physics. We explore the conformational,
electronic and recognition properties of our compounds using a wide range of
spectroscopic and analytical techniques, and we collaborate with many groups
of physicists, physical chemists and cell biologists.
1. Rotaxane Encapsulated Dyes
Synthetic dyes enrich many aspects of everyday life and they have high-tech applications in opto-electronics and molecular biology. Many chromophores have undesirable reactivity; we are addressing this problem by encapsulating dyes inside macrocycles, to form rotaxanes. Encapsulation protects the dye from the environment and modifies its properties in a variety of ways.
Collaborators: Seth Marder (Georgia Tech, USA), Saif Haque (IC, London), Hagan Bayley (Oxford, Chemistry).
 
(Figures: structure of a cyanine dye [3]rotaxane; a rotaxane inside live human bladder cells.)
2. Drugs for Photodynamic Therapy
Photodynamic therapy (PDT) is a technique for killing diseased cells using the excited state of a dye (see here for information on PDT). We are developing porphyrin-based drugs for PDT via two-photon excitation.
Collaborators: David Phillips (IC, London), Brian Wilson (Toronto), Klaus Suhling (Kings, London).
 
(Figures: human cancer cells strained with a porphyrin drug synthesised recently in Oxford.)
3. Insulated Molecular Wires - Polyrotaxanes
We are investigating insulated molecular wires which consist of conjugated polymers threaded through cylindrical insulating macrocycles. Our approach is to bind the monomer inside the macrocycle, polymerise it to form a sheathed conjugated polymer, then cap the ends to prevent unthreading. Binding is achieved by the hydrophobic effect and polymerisation is done in water. Insulation enhances the stability and luminescence of the molecular wire while preserving its semiconductivity.
Collaborators: Franco Cacialli (UCL, London), Paolo Samor (Strasbourg, France), Laura Herz (Oxford).
(Figure: model of an insulated molecular wire; β-cyclodextrin rings shown in green)
4. Porphyrin-Based Molecular Wires
We are using porphyrin macrocycles to prepare polymers with unusual electronic properties, and testing their ability to carry electrons over long distances. These materials have applications in optoelectronics and nonlinear optics.
Collaborators: Richard Nichols (Liverpool), Emyr Macdonald (Cardiff), Bo Albinsson (Chalmers, Sweden), Laurens Siebbeles (Delft, The Netherlands).
5. Dyes for Two-Photon Absorption
The simultaneous absorption of two photons is a rare event with most dyes. We are developing chromophores with strong two-photon absorption for applications in optical data storage, microfabrication, microscopy and PDT.
Collaborators: Aleks Rebane and Mikhail Drobizhev (Montana, USA), Jean-Luc Brdas (Georgia Tech, USA).
(Figure: a ladder polymer with enhanced two-phon absorption. Ladder formation holds the π-system flat.)
Selected Publications (a complete list is available here)
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Template-Directed Synthesis of a π-Conjugated Porphyrin Nanoring.
M. Hoffmann, C.J. Wilson, B. Odell and H.L. Anderson
- Angew. Chem. Int. Ed. 2007, 46, in press.
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Insulated Molecular Wires.
M.J. Frampton and H.L. Anderson
- Angew. Chem. Int. Ed. 2007, 46, 1028-1064.
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Homo- and Hetero-[3]Rotaxanes with Two π-Systems Clasped in a Single Macrocycle.
E.J.F. Klotz, T.D.W. Claridge and H.L. Anderson
- J. Am. Chem. Soc.
2006, 128, 15374-15375.
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Enzymatic Synthesis and Photoswitchable Enzymatic Cleavage of a Peptide-Linked Rotaxane.
A.G. Cheetham, M.G. Hutchings, T.D.W. Claridge and H.L. Anderson
- Angew. Chem. Int. Ed. 2006, 45, 1596-1599.
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Strong Cooperative Enhancement of Two-Photon Absorption in Double-Strand Conjugated Porphyrin Ladder Arrays.
M. Drobizhev, Y. Stepanenko, A. Rebane, C.J. Wilson, T.E.O. Screen, and H.L. Anderson
- J. Am. Chem. Soc.
2006, 128, 12432-12433.
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Cyclodextrin-threaded conjugated polyrotaxanes as insulated
molecular wires with reduced interstrand interactions.
F. Cacialli, J.S. Wilson, J.J. Michels, C. Daniel, C. Silva,
R.H. Friend, N. Severin, P. Samor, J.P. Rabe,
M.J. O'Connell, P.N. Taylor and H.L. Anderson
- Nature Materials
2002, 1, 160-164.
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Building molecular wires from the colours of life: conjugated porphyrin oligomers.
H.L. Anderson
Chem. Commun.
1999, 2323-2331.
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