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Professor Cameron J Kepert

ARC Future Fellow and Professor of Chemistry

Contact Details

School of Chemistry, Building F11
The University of Sydney, NSW, 2006
Australia
Email address: cameron.kepert@sydney.edu.au
Telephone: +61 (2) 9351-5741
Fax: +61 (2) 9351-3329
Home Page: http://sydney.edu.au/science/chemistry/~cjkgroup/

Career Profile

BSc (Hons. I), University of Western Australia

PhD, Royal Institution of Great Britain/University of London

Junior Research Fellow (Christ Church), University of Oxford

Appointed at the University of Sydney, 1999

Rennie Medal, RACI, 2003

Le Fèvre Prize, Australian Academy of Science, 2004

Edgeworth David Medal, Royal Society of NSW, 2004

Malcolm McIntosh Prize for Physical Scientist of the Year, 2005

ARC Federation Fellowship, 2005

Alan Sargeson Award, RACI, 2006

Liversidge Lectureship, RSNSW, 2008

Australasian Lectureship, RSC, 2009

Areas of interest

  • Materials chemistry

  • Molecular framework materials

  • X-ray diffraction

  • Nanoporosity

  • Electronic and magnetic properties of solids

  • Phase transitions (structural, electronic and magnetic)

Research

Coordination Framework Materials

Coordination frameworks are crystalline solids that contain extended networks constructed by the linkage of metal atoms by multiply-coordinating polydentate ligands. A rapid growth in the study of these materials has arisen from the realisation that metal-organic framework synthesis offers considerable flexibility and control over structure and properties, thereby offering rare pathways to rational materials design. This flexibility originates from the enormous structural and chemical diversities afforded by molecular systems, features that are less prevalent in many other branches of materials chemistry.

The recent emergence of nanoporosity in molecular frameworks has led to widespread speculation that such materials may be ideally suited for applications such as molecular separation, sensing and heterogeneous catalysis. Our primary research efforts are being directed towards exploring these issues, addressing, in particular, whether there are any limitations to this porosity and to what extent the frameworks may be thought of as rigid. Experimentation involves the synthesis of new materials by diffusion-controlled and solvothermal methods, and structural and physical characterisations using techniques that include single crystal and powder X-ray diffraction, vibrational spectroscopy (IR and Raman), TGA/DSC of guest desorption and sorption, NMR, SQUID magnetometry, EPR and theoretical modelling of guest molecule docking and packing.

Chiral Phases: The search for chiral nanoporous materials, widely regarded as a Holy Grail within solid state chemistry, is driven by the potential application of such materials for chiral separations and enantioselective syntheses. We have recently made significant in-roads into this area by developing a large and diverse array of porous, chiral molecular framework solids, including some that are the only such materials known that can be synthesised homochirally. Experiments show that these materials display a high degree of selectivity to molecular guest-exchange, as well as retaining structural framework integrity with guest removal. Investigations into the direct application of these phases for enantioseparation are underway, with an aim towards designing systems for the separation of small drug-precursor molecules.

In-situ Structural Investigations: We have recently performed unique in-situ single crystal X-ray diffraction experiments of guest desorption and sorption to demonstrate the nanoporosity of specific molecular framework materials. These studies are noteworthy in providing the first quantitative proof that desolvated phases of both co-ordination and hydrogen-bonded framework lattices may be robust enough to support large regions of complete void, thereby drawing a direct link with more conventional nanoporous materials such as zeolites. Such studies are being combined with in-situ techniques such as DSC/TGA, vibrational spectroscopy, NMR and molecular modelling to generate an overall picture that combines structural information with an understanding of the selectivity, dynamics and energetics of guest-exchange.

Electronic and Magnetic Properties: The incorporation of atomic or molecular constituents with electronic or magnetic function (e.g., localised electrons, delocalised pI-systems, redox-active species, etc.) into molecular frameworks is being investigated with an aim towards constructing materials with novel electronic and magnetic properties. The vast control over structure and chemical functionality that is afforded by this molecular approach allows the property-directed design and synthesis of new magnetic and electronic materials, including, importantly, the possible combination of these properties with nanoporosity.

Hydrogen Storage: The safe and efficient storage of hydrogen gas represents one of the central challenges on the road to the proposed Hydrogen Economy. Nanoporous coordination framework materials have recently been shown to sorb large volumes of hydrogen gas at low temperature and high pressure, a property that may be attributed to their very high surface areas. Two principal challenges exist to optimise the extent and conditions of loading: 1) maximisation of surface area per mass and volume, thereby maximising potential uptake, and 2) maximisation of the dihydrogen physisorption interaction energy, thereby favouring loading at higher temperatures and lower pressures. Our investigations in this area have uncovered very high hydrogen uptakes in Prussian Blue materials and a range of highly porous metal-organic frameworks.

Negative Thermal Expansion: We have recently discovered that a broad family of coordination frameworks undergo negative thermal expansion (NTE, ie. contraction upon warming) over broad temperature ranges. We attribute this highly unusual and potentially useful property to the existence of low energy transverse vibrations of molecular bridges within the open framework structures, the amplitude of which increase with increasing temperature. Through tuning the energy of these vibrational modes we have achieved both unprecedented NTE and approximate zero thermal expansion (ZTE) behaviour.

Publications (2009 to 2011)

  1. Li, F; Clegg, JK; D'Alessandro, DM; Goux-Capes, L; Sciortino, NF; Keene, TD and Kepert, CJ. Self-assembled Co(II) molecular squares incorporating the bridging ligand 4,7-phenanthrolino-5,6:5´,6´-pyrazine. Dalton Transactions, 40 (45), 12388-12393, 2011. DOI: 10.1039/c1dt11254f

  2. Li, F; Clegg, JK and Kepert, CJ. Structural diversity in coordination polymers constructed from a naphthalene-spaced dipyridyl ligand and iron(II) thiocyanate. Journal of Inclusion Phenomena and Macrocyclic Chemistry, 71 (3-4), 381-388, 2011. DOI: 10.1007/s10847-011-0016-5

  3. Mulyana, Y; Lindoy, LF; Kepert, CJ; McMurtrie, J; Parkin, A; Turner, P; Wei, G and Wilson, JG. New metal organic frameworks incorporating the ditopic macrocyclic ligand dipyridyldibenzotetraaza[14]annulene. Journal of Inclusion Phenomena and Macrocyclic Chemistry, 71 (3-4), 455-462, 2011. DOI: 10.1007/s10847-011-0007-6

  4. Keene, TD; Murphy, MJ; Price, JR; Price, DJ and Kepert, CJ. A new modification of an old framework: Hofmann layers with unusual tetracyanidometallate groups. Dalton Transactions, 40 (43), 11621-11628, 2011. DOI: 10.1039/c1dt11183c

  5. Dunstan, MT; Southon, PD; Kepert, CJ; Hester, J; Kimpton, JA and Ling, CD. Phase diagram, chemical stability and physical properties of the solid-solution Ba4Nb2-xTaxO9. Journal of Solid State Chemistry, 184 (10), 2648-2654, 2011. DOI: 10.1016/j.jssc.2011.07.036
  6. Southon, PD; Price, DJ; Nielsen, PK; McKenzie, CJ and Kepert, CJ. Reversible and selective O2 chemisorption in a porous metal–organic host material. Journal of the American Chemical Society, 133 (28), 10885-10891, 2011. DOI: 10.1021/ja202228v

  7. Keene, TD; Price, DJ; Kepert, CJ. Laboratory-based separation techniques for insoluble compound mixtures: Methods for the purification of metal-organic framework materials. Dalton Transactions, 40 (27), 7122-7126, 2011. DOI: 10.1039/c1dt10251f

  8. Peterson, VK; Brown, CM; Liu, Y and Kepert, CJ. Structural study of D2 within the trimodal pore system of a metal organic framework. The Journal of Physical Chemistry C, 115 (17), 8851-8857, 2011. DOI: 10.1021/jp2010937

  9. Li, F; Clegg, JK; Goux-Capes, L; Chastanet, G; D'Alessandro, DM; Létard, J-F and Kepert, CJ. A mixed-spin molecular square with a hybrid [2x2]grid/metallocyclic architecture. Angew. Chem. Int. Ed., 50 (12), 2820-2823, 2011. DOI: 10.1002/anie.201007409

  10. Kepert, CJ. Metal-organic framework materials. Book chapter in: Porous Materials. ISBN: 978-0-470-99749-9. Editors: Bruce, DW; O'Hare, D and Walton, RI. Published by John Wiley & Sons, Ltd, Chapter 1, pp. 1-67, 2011.

  11. Li, F; Clegg, JK; Price, D and Kepert, CJ. Self-assembly of a metallomacrocycle templated by iron(II). Inorganic Chemsitry, 50 (3), 726-728, 2011. DOI: 10.1021/ic102350t

  12. Lock, N; Wu, Y; Christensen, M; Cameron, SL; Peterson, VK; Bridgeman, AJ; Kepert, CJ and Iversen, BB. Elucidating negative thermal expansion in MOF-5. Journal of Physical Chemistry C, 114 (39), 16181-16186, 2010. DOI: 10.1021/jp103212z

  13. Yuan, A-H; Southon, PD; Price, DJ; Kepert, CJ; Zhou, H and Liu, W-Y. Syntheses, crystal structures, and the phase transformation of octacyanometallate-based LnIII–WV bimetallic assemblies with two-dimensional corrugated layers. Eur. J. Inorg. Chem., (23), 3610-3614, 2010. DOI: 10.1002/ejic.201000320

  14. Wu, H; Simmons, JM; Liu, Y; Brown, CM; Wang, X-S; Ma, S; Peterson, VK; Southon, PD; Kepert, CJ; Zhou, H-C; Yildirim, T and Zhou, W. Metal-organic frameworks with exceptionally high methane uptake: Where are how is methane stored? Chem. Eur. J., 16 (17), 5205-5214, 2010. DOI: 10.1002/chem.200902719

  15. Peterson, VK; Kearley, GJ; Wu, Y; Ramirez-Cuesta, AJ; Kemner, E and Kepert, CJ. Local vibrational mechanism for negative thermal expansion: A combined neutron scattering and first-principles study. Angew. Chem. Int. Ed., 49 (3), 585-588, 2010. DOI: 10.1002/anie.200903366

  16. Phillips, AE; Halder, GJ; Chapman, KW; Goodwin, AL and Kepert, CJ. Zero thermal expansion in a flexible, stable framework: Tetramethylammonium copper(I) zinc(II) cyanide. J. Am. Chem. Soc., 132 (1), 10-11, 2010. DOI: 10.1021/ja906895j

  17. Clegg, JK; Iremonger, SS; Hayter, MJ; Southon, PD; Macquart, RB; Duriska, MB; Jensen, P; Turner, P; Jolliffe, KA; Kepert, CJ; Meehan, GV and Lindoy, LF. Hierarchical self-assembly of a chiral metal-organic framework displaying pronounced porosity. Angew. Chem. Int. Ed., 49 (6), 1075-1078, 2010. DOI: 10.1002/anie.200905497

  18. Amoore, JJM; Neville, SM; Moubaraki, B; Iremonger, SS; Murray, KS; Létard, J-F and Kepert, CJ. Thermal- and light-induced spin crossover in a guest-dependent dinuclear iron(II) system. Chem. Eur. J., 16 (6), 1973-1982, 2010. DOI: 10.1002/chem.200901809

  19. Duriska, MB; Neville, SM; Lu, J; Iremonger, SS; Boas, JF; Kepert, CJ and Batten, SR. Systematic metal variation and solvent and hydrogen-gas storage in supramolecular nanoballs. Angew. Chem. Int. Ed., 48 (47), 8919-8922, 2009. DOI: 10.1002/anie.200903863

  20. Kepert, CJ. Supramolecular magnetic materials. Aust. J. Chem., 62 (9), 1079-1080, 2009. DOI: 10.1071/CH09399

  21. Neville, SM; Halder, GJ; Chapman, KW; Duriska, MB; Moubaraki, B; Murray, KS and Kepert, CJ. Guest tunable structure and spin crossover properties in a nanoporous coordination framework material. J. Am. Chem. Soc., 131 (34), 12106-12108, 2009. DOI: 10.1021/ja905360g

  22. Southon, PD; Liu, L; Fellows, EA; Price, DJ; Halder, GJ; Chapman, KW; Moubaraki, B; Murray, KS; Letard, JF and Kepert, CJ. Dynamic interplay between spin-crossover and host-guest function in a nanoporous metal-organic framework material. Journal of the American Chemical Society, 131 (31), 10998-11009, 2009.

  23. Kumagai, H; Akita-Tanaka, M; Kawata, S; Inoue, K; Kepert, CJ and Kurmoo, M. Synthesis, crystal structures, and properties of molecular squares displaying hydrogen and pi-pi bonded networks. Crystal Growth & Design, 9 (6), 2734-2741, 2009. DOI: 10.1021/cg801369u

  24. Goodwin, AL; Kennedy, BJ and Kepert, CJ. Thermal expansion matching via framework flexibility in zinc dicyanometallates. Journal of the American Chemical Society, 131 (18), 6334, 2009. DOI: 10.1021/ja901355b

  25. Brown, CM; Liu, Y; Yildirim, T; Peterson, VK and Kepert, CJ. Hydrogen adsorption in HKUST-1: a combined inelastic neutron scattering and first-principles study. Nanotechnology, 20 (20), 204025, 2009. DOI: 10.1088/0957-4484/20/20/204025

  26. Duriska, MB; Neville, SM; Moubaraki, B; Cashion, JA; Halder, GJ; Chapman, KW; Balde, C; Letard, JF; Murray, KS; Kepert, CJ and Batten, SR. A nanoscale molecular switch triggered by thermal, light, and guest perturbation. Angewandte Chemie-International Edition, 48 (14), 2549-2552, 2009. DOI: 10.1002/anie.200805178