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Professor Mike Ward

Professor Mike Ward

Head of Dept. of Chemisty of Department

Phone: 0114 22 29484
Phone: +44 (0)114 222 9319 (secretary)
Fax: 0114 222 9346
Room Number: C86

Professor: BA, University of Cambridge (1986); PhD, University of Cambridge, with Dr. Ed. Constable (1989); Postdoctoral Research, Université Louis Pasteur de Strasbourg, with Dr. Jean-Pierre Sauvage (1989-1990); Lecturer/Reader/Professor, University of Bristol (1990-2003); Professor of Inorganic Chemistry, University of Sheffield (2003-present).

Awards

RSC Corday-Morgan Medal and Prize (1999); RSC Sir Edward Frankland Fellowship (2000 – 2001); RSC Industrially-sponsored award for Chemistry of the Transition Metals (2005)

Keywords

Coordination chemistry; ligand design; supramolecular chemistry; transition metals; lanthanides; optical and electrochemical properties of metal complexes; photophysical properties of metal complexes; spectroelectrochemistry.

Research Interests

My research interests cover all aspects of the preparation, structural characterisation, and physical properties (electrochemical, magnetic, optical and photophysical) of complexes based on transition-metal (d-block) and lanthanide (f-block) elements. As such the work is interdisciplinary and covers many aspects of inorganic, organic, physical and materials chemistry. Currently active areas of interest include the following.


Self-assembly and host-guest chemistry of supramolecular cage complexes. Reaction of relatively simple bridging ligands with labile first-row transition metal ions can afford remarkably elaborate high-nuclearity cage complexes which bind anionic guests in their central cavity. In some cases the central anions act as templates to induce the assembly of the cage around them. The largest example we have characterised so far is a tetra-capped, truncated tetrahedral cage containing sixteen Zn(II) ions, twenty four bridging ligands, and thirty two anion. Such cage complexes are of interest not only for their structures but also for their host-guest chemistry associated with anion uptake into their central cavities, and their photophysical properties.

Photophysical properties of polynuclear assemblies. Complexes in which a light-absorbing group with a long excited-state lifetime (commonly, a Ru(II)-polypyridyl unit) is attached to a metal fragment which can use the excited-state energy, either in a redox reaction or by accepting it to enter an excited state of its own, are of particular interest in a variety of fields ranging from solar energy harvesting to display devices. Particular emphases at the moment are on

(i) the use of strongly-absorbing d-block chromophores to sensitise long-wavelength luminescence from lanthanides such as Er(III), Yb(III) and Nd(III) in d-f polynuclear assemblies;

(ii) use of `solvatochromism´ and `metallochromism´ as a mechanism for controlling and switching long-range photoinduced energy-transfer in polynuclear complexes;

(iii) the supramolecular chemistry of luminescent cyanometallate complexes such as [Ru(bipy)(CN)4]2- and [Os(bipy)(CN)4]2-: crystal engineering and hydrogen bonding;

(iv) Use of picosecond time-resolved infra-red spectroscopy to understand photoinduced energy and electron transfer in polynuclear assemblies.

Redox and spectroelectrochemical properties of polynuclear complexes. Complexes which contain several metal centres connected by suitable bridging ligands can show extensive redox activity. Coupling of the techniques of electrochemistry (generating compounds in different oxidation states) and UV/Vis or infrared spectroscopy results in spectroelectrochemistry, in which unstable oxidation states are electrochemically generated and their UV/Vis or IR spectra recorded in situ to provide spectral information on compounds which are too unstable to be isolated chemically. This can provide information on e.g. where the electrons that were gained or lost in the redox process are localised, and how effective different bridging ligands are at mediating electronic delocalisation between metal centres. Redox-active complexes which show dramatic colour changes in different oxidation states can be used as `electrochromic dyes´, and attachment of such species to conducting surfaces allows preparation of rapidly-switchable `electrochromic windows´ whose transmission of light changes quickly as a function of applied potential.

Publications uSpace Apply

University of Sheffield
Dept. of Engineering Materials
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