Inorganic Chemistry
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 areas that are actively pursued in Cardiff are summarised below. For further details please contact the staff members involved in a particular area of research.
Ligand Design and Coordination Chemistry
The design of new ligands is central to the research carried out in the group. Ligands currently being developed include novel phosphines, particularly the important phosphine macrocycles including combined phosphine-carbene macrocycles (Edwards) and the properties of their metal complexes in catalysis and other applications, unique N-heterocyclic carbenes (NHCs) and related species, functionalized NHCs (Cavell, Dervisi), and chiral carbene based ligand systems. Novel N and S donor ligands are also being successfully developed and exploited in various applications. Other groups are involved in the development of chiral ligands for use in asymmetric catalysis (Fallis, Ward). This research is predominantly synthetic in nature involving multi-step organic and inorganic syntheses.
Responsive Systems
Responsive probes with a measurable output can be designed to target a wide range of anions, cations and molecular entities such as toxic chemicals or biologically important analytes and have wide-ranging applications in analytical, materials and biomedical research fields. Several groups are interested in 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. These systems can be designed as single molecular entities or components of larger macrocmolecules such as micelles or surface modified nanoparticles. Recent publications highlight examples on the electrochemical detection of fluoride ions using borylated ferrocenes (Fallis) and the luminescent detection of metal cations using lanthanide complexes (Pope).
Catalysis
A number of fundamental studies are underway within the Group, which model and develop catalysts and catalytic reactions. The research involves experimental aspects, in which model catalyst systems are synthesised and studied spectroscopically (Cavell, Ward); this work is often supported by computational studies in a synergistic combination of theory and ex periment. The research involves close collaboration with colleagues in other research groups within the department. Specific examples include the isolation of catalytic intermediates using N-heterocyclic carbene based ligands (Cavell), the development of a new series of bis(carbene) ligands containing a hemilabile pyridyl donor (Cavell, Ward), and the development of chiral catalysts based upon calcium (Ward).
Imaging
Several groups within the Inorganic research group in 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 (Amoroso, Edwards, Fallis), applications of paramagnetic species as MRI contrast agents (Amoroso, Edwards, Fallis, Pope) to optical techniques and in particular fluorescence microscopy with transition metal complexes (Amoroso, Pope). 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
Applied Spectroscopy
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 (Pope). 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, which is housed within the School, is therefore a key spectroscopic tool, providing 1H nuclear magnetic resonance dispersion (NMRD) 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 macromolecular biomolecules and ions (Amoroso, Edwards, Pope).
New Molecules and Materials for Photovoltaic Applications
Work towards increasing the efficiency of photovoltaic devices is 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. New chromophores based upon aryl-functionalised thiazolo[5,4-d]thiazole heterocycles are also being developed for such applications. 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 (Pope).
Publications from the group in 2011
Co-ordination of a new bis-terpyridine ligand with cupric perchlorate yielding a dinuclear M2L species. J.C. Knight, R. Prabaharan, P.G. Edwards, A.J. Amoroso. J. Mol. Struc., 2011, 989, 86-90. DOI: 10.1016/j.molstruc.2011.01.009
Bimodal, dimetallic lanthanide complexes that bind to DNA: the nature of binding and its influence on water relaxivity. J.E. Jones, A.J. Amoroso, N.J. Buurma, I.M. Dorin, G. Parigi, B.D. Ward, S.J.A. Pope, Chem. Commun., 2011, 47, 3374. DOI: 10.1039/c1cc00111
First examples of structurally imposing eight-membered ring (diazocanylidene) N-heterocyclic carbenes: salts, free carbenes, and metal complexes. W. Y. Lu, Y. Wei, K. J. Cavell Kingsley, J. S. Wixey, B. Kariuki, Organometallics, 2011, 30, 5649-5655. DOI: 10.1021/om200467x
intramolecular formation of CrI(bis-arene) species via TEA activation of a CrI complex [Cr(CO)4(Ph2P(R)PPh2)]+; An EPR and DFT investigation. L. E. McDyre, E. Carter, K.J. Cavell, D.M. Murphy, B. D. Ward, J. Platts, K. Stampford, W. F. Gabrielli, M.J. Hanton, D.M. Smith. Organometallics, 2011, 30, 4505-4508. DOI: 10.1021/om2006062
Structural studies of diethyltin(IV) derivatives and their biological aspects as potential antitumor agents against Agrobacterium tumefacien cells. M. Hussain, Zia-ur-Rehman; M. Hanif, K. J. Cavell et al., Appl. Organometal. Chem., 2011, 25, 412-419. DOI: 10.1002/aoc.1777
Novel quasi-scorpionate ligand structures based on a bis-N-heterocyclic carbene chelate core: synthesis, complexation and catalysis. S. Yasar, K. J. Cavell, B. D. Ward, et al., Appl. Organometal. Chem., 2011, 25, 374-382 DOI: 10.1002/aoc.1773
Rhodium and iridium complexes of an asymmetric bicyclic NHC bearing secondary pyridyl donors. P. D. Newman, K. J. Cavell, A. J. Hallett and B. M. Kariuki, Dalton Trans., 2011, 40, 8807-8813. DOI: 10.1039/c1dt10582e
Expanded ring N-heterocyclic carbenes: A comparative study of ring size in palladium (0) catalysed Mizoroki-Heck coupling. J. J. Dunsford and K. J. Cavell, Dalton Trans., 2011, 40, 9131-9135. DOI: 10.1039/c1dt10596e
Novel Intramolecular C(Aryl)-S Bond Activation by an Electron Rich, Ring-Expanded-NHC-Rh centre: A Combined Experimental and DFT Study. Binobaid, K. J. Cavell, M. S. Nechaev and B. M. Kariuki, Australian J. Chem., 2011, 64, 1141-1147 DOI: 10.1071/CH11243
Expanded ring N-heterocyclic carbene complexes of zero valent platinum dvtms (divinyltetramethyldisiloxane): Highly efficient hydrosilylation catalysts. J. J. Dunsford, K. J. Cavell and B. Kariuki, J. Organomet. Chem., 2011, 696, 188-194. DOI: 10.1016/j.jorganchem.2010.08.045
Complexes in context: Attempting to control the cellular uptake and localisation of rhenium fac-tricarbonyl polypyridyl complexes. R. G. Balasingham, M. P. Coogan and F. L. Thorp-Greenwood, Dalton Trans., 2011, 40, 11663-11674. DOI: 10.1039/c1dt11219h
Carbohydrate and amino acid metabolism of Spironucleus vortens. C. O. M. Millet, D. Lloyd, M. P. Coogan, J. Rumsey and J. Cable, Exper. Parasitology, 2011, 129, 17-26. DOI: 10.1016/j.exppara.2011.05.025
Multimodal radio-(PET/SPECT) and fluorescence imaging agents based on metallo-radioisotopes: current applications and prospects for development of new agents. F. L. Thorp-Greenwood and M. P. Coogan, Dalton Trans., 2011, 40, 6129-6143. DOI: 10.1039/c0dt01398f
A 'Sleeping Trojan Horse' which transports metal ions into cells, localises in nucleoli, and has potential for bimodal fluorescence/PET imaging. F. L. Thorp-Greenwood, V. Fernandez-Moreira, C. O. Millet, C. F. Williams, J. Cable, J. B. Court, A. J. Hayes, D. Lloyd and M. P. Coogan, Chem. Commun., 2011, 47, 3096-3098. DOI: 10.1039/c1cc10141b
Chiral Silver and Gold Rings: Synthesis and Structural, Spectroscopic, and Photophysical Properties of Ag and Au Metallamacrocycles of Bridging NHC Ligands. C. Carcedo, J.C. Knight, I.A. Fallis, S.J.A. Pope, A. Dervisi, Organometallics, 2011, 30, 2553-2562. DOI: 10.1021/om200125w
Metal Complexes of a Structurally Embellished Phosphinane Ligand: An Assessment of Stereoelectronic Effects. P.G. Edwards, B.M. Kariuki, M. Limon, Li-Ling Ooi, J.A. Platts, P.D. Newman, Eur. J. Inorg. Chem., 2011, 8, 1230-1239. DOI: 10.1002/ejic.201001170
Coordination behaviour in transition metal complexes of asymmetric NPN ligands. P.G. Edwards, B. Kariuki, P.D. Newman, Polyhedron, 2011, 30, 935-941. DOI: 10.1016/j.poly.2010.12.029
Coordination chemistry of an asymmetric P,N,O tridentate ligand containing primary phosphine, amine and alcohol donors. P.G. Edwards, P.D. Newman, A. Stasch, J. Organomet. Chem., 2011, 696, 1652-1658. DOI: 10.1016/j.jorganchem.2011.01.031
Iron(II) template synthesis of benzannulated triphospha- and triarsamacrocycles. T.Albers, J. Baker (ne´e Johnstone), S.J. Coles, P. G. Edwards, B. Kariuki and P.D. Newman, Dalton Trans., 2011, 40, 9525-9532. DOI: 10.1039/c0dt01724h
Evaluation of a Fluorescent Derivative of AMD3100 and its Interaction with the CXCR4 Chemokine Receptor. J.C. Knight, A.J. Hallett, A. Brancale, S.J. Paisey, R.W. E. Clarkson, and P. G. Edwards, ChemBioChem 2011, 12, 2692-2698. DOI: 10.1002/cbic.201100441
Synthesis and coordination chemistry of macrocyclic ligands featuring NHC donor groups. P.G. Edwards and F. Ekkehardt Hahn, Dalton Trans., 2011, 40, 10278-10288. DOI: 10.1039/C1DT10864F
Structure & EPR characterization of N,N’-bis(5-tert-butylsalicylidene)-1,2-cyclohexanediamino-vanadium (IV) oxide and its adducts with propylene oxide. E. Carter, I. A. Fallis, B. M. Kariuki, I. R. Morgan, D. M. Murphy, T. Tatchell, S. Van Doorslaer, E. Vinck. Dalton Trans., 2011, 40, 7454-7462. DOI: 10.1039/c1dt10378d
Visualising diastereomeric interactions of chiral amine-chiral copper Salen adducts by EPR spectroscopy and DFT. D. M. Murphy, I. Caretti, E. Carter, I. A. Fallis, M. C. Göbel, J. Landon, S. Van Doorslaer and D.J. Willock. Inorg. Chem., 2011, 50, 6944-6955. DOI: 10.1021/ic200113u
Interactions of an asymmetric amine with a non-C2 symmetric Cu-salen complex: An EPR/ ENDOR and HYSCORE Investigation. Caretti, E. Carter, I. A. Fallis, D. M. Murphy, S. Van Doorslaer, Phys. Chem. Chem. Phys., 2011, 13, 20427-20434. DOI: 10.1039/c1cp22522g
Structural, spectroscopic and redox properties of uranyl complexes with a maleonitrile containing ligand. H.C. Hardwick, D.S. Royal, M. Helliwell, S.J.A. Pope, C.A. Sharrad, Dalton Trans., 2011, 40, 5939. DOI: 10.1039/c0dt01580f
Luminescent probes based on water-soluble, dual-emissive lanthanide complexes: metal ion-induced modulation of near-IR emission. M. Andrews, J.E. Jones, L.P. Harding, S.J.A. Pope, Chem. Commun. 2011, 47, 206. DOI: 10.1039/c0cc00210k
Amino-anthraquinone chromophores functionalised with 3-picolyl units: structures, luminescence, DFT and their coordination chemistry with Re(I) di-imine complexes. J.E. Jones, B.M. Kariuki, B.D. Ward, S.J.A. Pope, Dalton Trans., 2011, 40, 3498. DOI: 10.1039/c0dt01383h
Towards near-IR emissive rhenium tricarbonyl complexes: synthesis and characterisation of unusual 2,2¢-biquinoline complexes. A.J. Hallett, S.J.A. Pope, Inorg. Chem. Commun., 2011, 14, 1606. DOI: 10.1016/j.inoche.2011.06.021
New 2,3-disubstituted-5-hydroxyquinoxaline ligands and their coordination chemistry with cyclometallated Ir(III): synthesis, structures and tunable electronic properties. A.J. Hallett, B.M. Kariuki, S.J.A. Pope, Dalton Trans., 2011, 40, 9474. DOI: 10.1039/c1dt10707k
Functional luminescent lanthanide complexes: metal ion induced modulation of visible luminescence from Eu(III) complexes. M. Andrews, B.M. Kariuki, S.J.A. Pope, Polyhedron. 2011, 30, 2055. DOI: 10.1016/j.poly.2011.05.008
Chiral Calcium Catalysts for Asymmetric Hydroamination/Cyclisation. J. S. Wixey and B. D. Ward, Chem. Commun., 2011, 47, 5449. DOI: 10.1039/c1cc11229e
Modular Ligand Variation in Calcium Bisimidazoline Complexes: Effects on Ligand Redistribution and Hydroamination Catalysis. J. S. Wixey and B. D. Ward Dalton Trans., 2011, 40, 7693. DOI: 10.1039/c1dt10732a
The Coordination Chemistry of Tris(3,5-dimethylpyrazolyl)methane Manganese Carbonyl Complexes: Synthetic, Electrochemical and DFT Studies A.J. Hallett, R. A, Baber, A. G. Orpen, and B. D. Ward Dalton Trans., 2011, 40, 9276. DOI: 10.1039/c1dt10828j
Cytotoxic activity, cell imaging and photocleavage of DNA induced by a Pt(II) cyclophane bearing 1,2 diamino ethane as a terminal ligand. N. Kumari, B. K. Maurya, R. K. Koiri, S. K. Trigun, S. Saripella, M. P. Coogan and L. Mishra, Med. Chem. Commun., 2011, 2, 1208-1216. DOI: 10.1039/C1MD00159K
The importance of cellular localisation of probes: synthesis, photophysical properties, DNA interactions and cellular imaging properties of rhenium dppz complexes with known cellular localisation vectors. F. L. Thorp-Greenwood, M. P. Coogan, L. Mishra, N. Kumari, G. Rai and S. Saripella, New J. Chem., 2012, 36, 64-72. DOI: 10.1039/C1NJ20662A