Primary research interest

Inorganic Chemistry - Spectroscopic properties of new materials

Additional role

Chief Examiner of Chemistry

Research focus and collaborations

Summary

  • Molecular spectroscopy
  • Low temperature (1.8-300K), High field (+/-7 Tesla), Linear/Circular polarised, 300-3000 nm
  • Electron paramagnetic resonance and Magnetic Circular Dichroism
  • Electronic and magnetic properties of inorganic complexes
  • Theoretical electronic structure calculations
  • Vibronic coupling and the Jahn-Teller effect
     

The pseudo-Jahn-Teller effect

Our contribution in this area has been to extend the theory of the Jahn-Teller effect to the low symmetry situations, which are more commonly realised in nature. I developed both the formalism and the computer code, resulting in some 40 publications on applications to EPR, XAFS and cystallographic experiments. This approach has now been adopted by others and is widely.

  • C. J. Simmons, H. Stratemeier, M. A. Hitchman, D. Reinen, V. M. Masters, M. J. Riley, “Temperature Dependence of the Crystal Structure and g-Values of trans-Diaqua Bis(methoxyacetato)Copper(II): Evidence for a Thermal Equilibrium Between Complexes with Tetragonally Elongated and Compressed Geometries.”, Inorganic Chemistry, 2011, 50, 4900-16.
  • K. S. Hadler, J. R. Kilmartin, G. R. Hanson, M. A. Hitchman, C. J. Simmons, M. J. Riley, “Vibronic Effects in Cu(II) doped Ba2Zn(HCO2)6.4H2O”, Inorganic Chemistry, 2008, 47; 8188-8196.

Six coordinate Cu(II) complexes

We have had a long interest in the spectroscopy of copper(II) compounds. We were the first reported fluorescence of a Cu(II) complex, and have recently studied the CuO6centre in Cu(II) doped MgO. This is the only known example of a Cu(II) system which displays a true dynamic Jahn-Teller effect.

  • M. J. Riley, C. Noble, P. L. W. Tregenna-Piggott, “The dynamic Jahn-Teller effect in Cu(II)/MgO”, in: Vibronic Interactions and the Jahn-Teller Effect, Eds C. Daul; M. Atanasov, Springer-Verlag, Heidelberg, 2012, pp. 85-103.
  • A. K. Dick, E. R. Krausz, K. S. Hadler, C. J. Noble, P. L. W. Tregenna-Piggott, M. J. Riley , “The Jahn-Teller effect in Cu(II) doped MgO”, Journal of Physical Chemistry C, 2008, 112, 14555-14562.

Bioinorganic spectroscopy

Recently I have been applying spectroscopic techniques such as Magnetic Circular Dichroism to the study of bioinorganic and bio-mimetic systems. Of particular interest are systems that have multiple metal centres that are magnetically coupled, or heme proteins.

  • S.J. Smith, R.A. Peralta, R. Jovito, A. Horn, A.J. Bortoluzzi, C.J. Noble, G.R. Hanson, R. Stranger, V. Jayaratne, G.  Cavigliasso, L.R. Gahan, G. Schenk, O.R. Nascimento, A. Cavalett, T. Bortolotto, G. Razzera, H. Terenzi, A. Neves, M.J. Riley, “Spectroscopic and Catalytic Characterization of a Promiscuous Functional Fe(III)Fe(II) Biomimetic for the Active Site of Uteroferrin and Protein (BSA) Cleavage”, Inorganic  Chemistry, 2012, 51, 2065–78
  • J. R. Kilmartin, M. J. Maher, K. Krusong, C. J. Noble, G. R. Hanson, P.V. Bernhardt, M. J. Riley, Ulrike Kappler, “Insights into Structure and Function of the Active Site of SoxAX Cytochromes”, Journal of Biological Chemistry, 286, 24872-81, 2011.

Iridium complexes

Organometallic Ir(III) complexes can have highly efficient luminescence that make them ideal in organic light emitting diode (OLED) applications. We have been using Magnetic Circular Dichroism (MCD) and Magnetic Circularly Polarised Luminescence (MCPL) to study the nature of the emitting states.

  • A. R. G. Smith, M. J. Riley, S.-C. Lo, I. R. Gentle, P. L. Burn, B. J. Powell, “Effects of Fluorination on Phosphorescent Iridium(III) Complexes Explored by Magnetic Circular Dichroism and Relativistic Time Dependant Density Functional Theory”, Inorganic  Chemistry, 2012, 51, 2821-31.
  • A. R. G. Smith, M. J. Riley, S.-C. Lo, P. L. Burn, I. R. Gentle, B. J. Powell, “Relativistic Effects in Phosphorescent Iridium(III) Complexes”, Physical Review B, 2011, 83, 041105/1-4.

Nanowires

Materials in lower dimensions can have interesting electronic structures and spectroscopic properties. We have used MCD and MCPL to study the spectra of impurity transitions metal ions as probes of the nanowires.

  • Z. Li, L. Cheng, Q. Sun, Z. Zhu, M. J. Riley, M. Aljada, Z. Cheng, X. Wang, G. R. Hanson, S. Qiao, S. C. Smith, G. Q. Lu,, "Diluted Magnetic Semiconductor Nanowires Prepared by the Solution–Liquid–Solid Method", Angewandte Chemie, 2010, 49, 2777-81.
  • Z. Li, A. Du, Q. Sun, M. Aljada, L. Cheng, M. J. Riley, Z. Zhu, Z. Cheng, X. Wang, J. Hall, E.R. Krausz, S. Qiao, S. C. Smith, G. Q. Lu, “Cobalt-doped Cadmium Selenide Diluted Magnetic Semiconductor Colloidal Nanowires” Chem. Comm. 2011, 47, 11894-6.

Lanthanide energy levels

We are developing a computer program to calculate the electronic energy levels and magnetic properties of ions with an open f-shell.

Teaching interests

  • CHEM1020 Chemistry for Science & Engineering
  • CHEM1021 General Chemistry
  • CHEM1022 Chemisty for Health Professions
  • CHEM2002 Physical Chemistry
  • CHEM2054 Experimental Chemistry
  • CHEM3010 Advanced Inorganic Chemistry

Achievements and awards 

  • 2009 - Member PAC XAFS committee, Australian Synchrotron.
  • 1995 - Member Australian Optical Society
  • 1995 - Member Optical Society of America.
  • 1985 - Member Royal Australian Chemical Institute

Selected publications