Research groups within the Inorganic Chemistry section formulate, and subsequently develop the applications of, coordination complexes containing main group and transition metals. The metals and types of ligand are numerous, and hence the applications are diverse. Research in Inorganic Chemistry therefore often lies at the interface with other scientific disciplines, including other chemistry sub-disciplines, physics, materials chemistry, and medical research.
The design of new ligands is central to the research carried out in all areas of Inorganic Chemistry. Ligands currently being developed include novel phosphines, particularly the important phosphine macrocycles and combined phosphine-carbene macrocycles, unique N-heterocyclic carbenes and related species, and the development of chiral ligands for use in asymmetric catalysis. This research is predominantly synthetic in nature involving multi-step organic and inorganic syntheses.
Groups are investigating new systems based upon novel ligands and/or functionalised coordination complexes for the development of chemosensors. Measurable responses are dictated by the nature of the probe and can therefore be monitored via modulated optical, luminescent, electrochemical or longitudinal proton relaxivity behaviour, depending on the targeted application.
Fundamental studies model and develop catalysts and catalytic reactions. The research involves experimental aspects, in which model catalyst systems are synthesised and studied spectroscopically; this work is often supported by computational studies in a synergistic combination of theory and experiment. The research involves close collaboration with colleagues in other research groups within the department.
Groups within the Inorganic research at Cardiff are interested in the application of metal complexes in biomedical imaging, ranging from radioimaging applications of complexes of radionuclides such as PET and SPECT, applications of paramagnetic species as MRI contrast agents to optical techniques and in particular fluorescence microscopy with transition metal complexes. Notable outputs from the groups include the developments of the 99mTc based heart imaging agent MyoviewTM and the development of the first rhenium bipyridyl cell imaging agents.
The detailed spectroscopic characterization of ligands and coordination complexes underpins all of the research undertaken within the Inorganic Chemistry group. In addition to the use of multinuclear NMR, IR and UV-vis. spectroscopies a range of more specialized advanced techniques are employed on a routine basis. For example, time-resolved luminescence measurements employing UV-vis-NIR detectors are employed to probe the excited states of a variety of d- and f-metal ion complexes, as well as novel organic chromophores. Such measurements are key to the exploitation of such complexes in applications such as sensors, confocal microscope cellular imaging and the design of new materials for photovoltaic devices.
Recent work has also focused on the design and synthesis of new prototypical complexes for use in magnetic resonance imaging (MRI). Field-cycling relaxometry is a key spectroscopic tool, providing 1H nuclear magnetic resonance dispersion plots, from which key parameters describing the physical properties of the complexes can be obtained. Recent work has investigated the relaxivity properties of highly paramagnetic gadolinium species, including the modulation of relaxivity through binding events with biomolecules such as DNA.
Work towards increasing the efficiency of photovoltaic devices is also being undertaken within the Inorganic Chemistry section. In particular, new light-harvesting molecules based upon transition metal complexes are being investigated, as well as novel hybrid materials based upon functionalized polymeric thiophene compounds. The work involves a comprehensive assessment of the electronic, photophysical and redox properties of the species in question and an assessment of the materials within prototype photovoltaic devices.