BSc Hons (UQ), PhD (UQ) Chemistry
Position: 
Senior Lecturer and ARC Future Fellow
Room: 
838
Phone: 
+61 7 336 53862
Biography: 

After completing undergraduate and postgraduate studies at The University of Queensland in 2004, I undertook postdoctoral research at the University of California, Berkeley, with Prof. Kenneth N. Raymond. I returned to Australia in mid 2008, after being awarded an ARC Postdoctoral Fellowship at the University of Melbourne. In 2011, I was appointed as an Adjunct Lecturer at UQ, and was also awarded a Marie-Curie International Fellowship, undertaken in the Photochemical Nanosciences Laboratory at the Università di Bologna, Italy. In May 2012, I returned to Brisbane, rejoining the University of Queensland as a Lecturer and ARC Future Fellow.

Brief Research Description: 
Lanthanide metal ions properties
Research Focus and Collaborations: 

 

Our research is focused on exploiting the unique luminescent and magnetic properties of the Lanthanide (Lanthanoid - IUPAC) series of metal ions. These metals, together with Y and Sc, are known as the rare earths, and are increasing utilised in high-end technological applications, which include high strength magnets (Nd), contrast agents for medical imaging (Gd), rechargeable batteries (La) and as catalytic converters for vehicle exhaust (Ce) to name a few.

"Lanthanons - these elements perplex us in our researches, baffle us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us; mocking, mystifying and murmuring strange revelations and possibilities."

- Sir William Crookes, address to the Royal Society (February 1887)

 

The unusual properties of the Ln(III) series can be traced to their electronic structures, which are characterised by the progressive filling of 4f atomic orbitals from Z = 57 (Lanthanum) to Z = 71 (Lutetium). The trivalent (+3) oxidation state is most common, and organic complexes of these oxophilic metals (hard Lewis acids) display large and variable coordination numbers (>6, typically 8-12). Bonding in their coordination complexes is primarily electrostatic, and non-directional, which results in variable coordination geometries that are principally governed by steric factors. Obtaining the desired control over this variability remains a challenging area of coordination chemistry.

Our current research projects relate to the development of organic lanthanide complexes for applications in several different areas, as summarised below.

Luminescent Imaging
Trivalent lanthanide cations have well known luminescence properties. Their Laporte forbidden emission bands are characteristically sharp and atom-like, as a result of the core nature of the 4f electronic orbitals involved. Moreover, their emission is much longer lived (μsec to msec) when compared to organic chromophores (nsec), allowing for improved sensitivity using time gating techniques. In particular, we are interested in further developing complexes of Yb(III) and Nd(III), which demonstrate emission in the Near Infra-Red (NIR) region. These wavelengths allow for the improved depth penetration of light through biological tissues, and emissive complexes are candidates for applications in NIR imaging using optical tomography.

Photodynamic Therapy
Due to their high atomic mass and paramagnetism, trivalent lanthanide cations exert a strong influence on the efficiency of intersystem crossing (eg. excited singlet to triplet state conversion) for organic molecules, via the enhancement of spin-orbit coupling. The long-lived excited triplet state of organic molecules can act as a photosensitiser for triplet ground state (3Σg) molecular oxygen, leading to formation of excited state (1Δg) singlet oxygen, which is a highly reactive molecule. 1O2 can cause significant oxidative stress and damage to cellular structures, forming the basis of photodynamic therapy (PDT). We are exploring the use of Ln(III) complexation as a way of influencing the properties of existing organic photosensitisers used for PDT, and developing new Ln(III) based compounds with enhanced efficacy.

Lanthanide Frameworks
Coordination Polymers (CP’s) (or Metal Organic Frameworks – MOF’s) are crystalline materials built from infinitely repeating units of (typically) rigid organic ligands interconnected by metal cations to form 1-, 2-, or 3 dimensional structures. Our research in this area involves the construction of CP/MOF's utilising Ln(III) metal cations (as opposed to more commonly used transition metals), in combination with organic ligands such as aromatic N-oxides. We are interested in the structural, magnetic, and luminescent properties of these materials, together with their applications in important industrial processes such as gas sorption, separation and storage.

 

 

Collaborators:
Dr. Colette Boskovic, University of Melbourne, Australia
Dr. Brendan Abrahams, University of Melbourne, Australia
Prof. Ken Ghiggino and A/Prof. Trevor Smith, University of Melbourne, Australia

International Collaborators:
Prof. Paola Ceroni, Università di Bologna, Italy
Prof. Kenneth N. Raymond, University of California, Berkeley, USA
Prof. Eric Vauthey, University of Geneva, Switzerland

Funded Projects: 

 

UQ Major Equipment and Infrastructure (MEI) Grant, 2012
Facilities for Integrated Bioinorganic and Materials Chemistry Research
Total Value of grant: A$267,000

ARC Future Fellowship Project, 2010-2013
Caged Lanthanides for use in Photo-Dynamic Therapy and Near Infra-Red imaging
Total value of grant: A$700,000

Marie-Curie International Incoming Research Fellowship, 2011-2012
Lanthanide Dendrimer-Polymer Hybrids (LN-DENDRI-POLS)
Total value of grant: €182,000 (~A$230,000)

ARC Discovery Project, 2008-2010
Novel Ln(III) Complexes & Polymeric Luminescent Chelates for Biomedical Imaging & Bioassay
Total value of grant: A$306,000

Teaching: 

Coordination chemistry, f-block chemistry, materials chemistry, spectroscopy

Significant Professional Activities and Awards: 

Chartered Chemist and Member of the Royal Australian Chemical Institute (RACI)

Member of the American Chemical Society (ACS)

Selected Publications: