BSc, MSc, PhD
Inorganic Chemistry

Projects

• Porphyrin complexes: designing new chemical bonds, sugar sensors, and anticancer agents.

  Metalloporphyrin complexes occur naturally in hemoglobin, myoglobin and cytochromes. Synthetic porphyrin complexes are used widely as catalysts, in new materials, and as potential therapeutic agents. These applications are possible because the porphyrin ligand imparts interesting and unusual properties to the chemistry of the central atom. An important recent area of chemistry concerns compounds containing bonds between transition metals and the heavier main group elements. One reason for this interest is the quest to understand the extent and nature of transition metal - main group element multiple bonds. This chemistry can be approached by using the porphyrin ligand to define the coordination sphere of either the main group or the transition metal fragment. This project involves the synthesis and characterisation of new main group porphyrin complexes, and of heterobimetallic porphyrin complexes containing both transition metal and main group elements.
  
  Our research group is the first in the world to prepare complexes containing boron coordinated to the porphyrin ligand. They are very unusual in that they contain two boron atoms coordinated in the porphyrin cavity, in contrast to almost every other porphyrin complex which contains only one coordinated atom. The resulting compounds could be useful in two areas, as sugar sensors, in which sugar molecules form covalent links to boronic acid groups, and in Boron Neutron Capture Therapy. BNCT utilizes the capture of slow thermal neutrons by ¹⁰B atoms located in the vicinity of tumour cells. Porphyrins are known to localize on the surface of solid tumours, and so a porphyrin or related expanded porphyrin containing coordinated boron atoms would be a useful target for BNCT. This project involves both fundamental studies directed at learning more about boron poprhyrin complexes, and also specific experiments designed to test their feasibility for use as sugar sensors or BNCT anticancer agents.



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• The chemistry of new materials for a sustainable future

  Advances in chemistry are essential to the design and synthesis of new materials and the development of new practices that will enable our current civilization to become sustainable. The concepts of Green Chemistry provide important guiding principles in this endeavor. Three research projects are offered under this umbrella. The first is concerned with solar energy conversion, and will involve the design and construction of supramolecular assemblies of photoactive molecules. The second project will be concerned with the utilization of atmospheric CO₂ as a renewable chemical feedstock. Carbon dioxide is one of the major greenhouse gases, and an important frontier in current research is the search for methods not only to reduce or eliminate net CO₂ emissions, but also to convert CO₂ into useful chemicals. The approach taken here will involve synthesis of metal complexes designed to chemically activate CO₂ and its subsequent conversion to useful molecules. The aim of the third project is to design and synthesis a metal complex which can act as an electrode catalyst for the reduction of oxygen in a fuel cell. A fuel cell is an electrochemical cell which derives energy from the reduction of O₂ and the oxidation of H₂, both of which give water as the product. A catalyst is required for the oxygen reduction process in order for the fuel cell to operate at maximum efficiency.These projects will be co-supervised by Assoc Prof Peter Boyd, Assoc Prof Penny Brothers, and Assoc Prof James Wright.

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• Metal complexes as potential imaging agents and anti-cancer drugs

  Inorganic medicinal chemistry is a rapidly developing field, spurred largely by the tremendous success of the Pt-based anti-cancer drugs like Cisplatin. The unique complexing and redox properties of metal centres can be exploited in the rational design and synthesis of new metal-based anti-cancer drugs. Hypoxia-selective and radiation activated anti-cancer drugs, in which the drug is activated either in the oxygen-deficient, chemically reducing environment of solid tumour cells, or during radiation therapy, are a particular target in this project. The synthesis and chemistry of new complexes of cobalt, chromium or ruthenium, containing small bioactive organic groups as ligands, will be explored. This project is in collaboration with Dr David Ware of the Auckland Cancer Research Centre (Faculty of Medicine), and new complexes will be screened for anti-cancer activity.
  
  Metal complexes containing encapsulating ligands are becoming increasingly important in medical imaging and therapeutic applications. Recent work from our group on the reactions of ligands coordinated to cobalt has led to the development of synthetic routes to new polydentate ligands which encapsulate the metal ion. This project will explore the extension of this chemistry to main group metals such as bismuth and antimony, in order to prepare kinetically inert complexes of these usually labile elements. The project is in collaboration with Dr David Ware.

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More Publications   

Recent Publications

Albrett, A.M.; Conradie, J.; Boyd, P. D. W.; Clark, G. R.; Ghosh, A.; Brothers, P. J.   Corrole as a binucleating ligand: preparation, molecular structure and DFT study of diboron corroles    J. Am. Chem. Soc. 2008, 130, 2888-2889  

Albrett, A.M.; Conradie, J.; Ghosh, A.; Brothers, P. J.   DFT survey of monoboron and diboron corroles: regio- and stereochemical preferences for a constrained, low-symmetry macrocycle.   Dalton Trans. 2008, 4464 - 4473  

Belcher, W. J.; Hodgson, M. C.; Sumida, K.; Torvisco, A.; Ruhlandt-Senge, K.; Ware, D. C.; Boyd, P. D. W.; Brothers, P. J.   Porphyrin complexes containing coordinated BOB groups: synthesis, chemical reactivity and the structure of [BOB(tpClpp)]2+    Dalton Trans. 2008, 1602-1614  

Brothers, P. J.   Boron complexes of porphyrins and related polypyrrole ligands: unexpected chemistry for both boron and the porphyrin    Chem. Commun. 2008, 2090 – 2102  

Hodgson, M. C.; Brothers, P. J.; Clark, G. R.; Ware, D.C.    Synthetic routes to mixed-ligand cobalt(III) dithiocarbamato complexes containing imidazole, amine and pyridine donors and the X-ray crystal structure of a cobalt(III) bis(dithiocarbamato) histamine complex.    J. Inorg. Biochem. 2008, 102, 789-797.  

Bollwein T, Brothers P J, Hermann H L, Schwerdtfeger P   Theoretical investigations into transition metal-group 13 element bonding: Comparison between ruthenium porphyrin and ruthenium carbonyl diyl compounds.   Organometallics. 21(24):5236-5242, 2002 Nov 25.   View Abstract

Brothers PJ   Organoelement chemistry of main-group porphyrin complexes [Review].   ADVANCES IN ORGANOMETALLIC CHEMISTRY, VOL 48. 48 PG. 289-342. 2001 [Figures].  

Brothers PJ   Organometallic chemistry of transition metal porphyrin complexes [Review].   ADVANCES IN ORGANOMETALLIC CHEMISTRY, VOL. 46. 46 PG. 223-321. 2001 [Figures].  

Grubisha DS, Guzei IA, Al-Salim N, Boyd PDW, Brothers PJ and Woo LK   Novel coordination in the first tellurium porphyrin complex: Synthesis and crystal structure of [Te(ttp)Cl-2].   Angewandte Chemie-International Edition. 40(24):4743-+, 2001.  

Weiss A, Pritzkow H, Brothers PJ and Siebert W   Coordinated B-2 bridges in porphyrins - Unexpected formation of a diborane(4)- from a diborylporphyrin.   Angewandte Chemie-International Edition. 40(22):4182-4184, 2001.  

Ware DC, Brothers PJ, Clark GR, Denny WA, Palmer BD and Wilson WR   Synthesis, structures and hypoxia-selective cytotoxicity of cobalt(III) complexes containing tridentate amine and nitrogen mustard ligands.   Journal of the Chemical Society-Dalton Transactions. (6):925-932, 2000.   View Abstract

Belcher WJ, Brothers PJ, Meredith AP, Rickard CEF and Ware DC   Tin complexes of tetramethyltetraazadibenzo[14]annulene: organometallic derivatives.   Journal of the Chemical Society-Dalton Transactions. (16):2833-2836, 1999.   View Abstract

Boyd PDW, Hodgson MC, Rickard CEF, Oliver AG, Chaker L, Brothers PJ, Bolskar RD, Tham FS and Reed CA   Selective supramolecular porphyrin/fullerene interactions.   Journal of the American Chemical Society. 121(45):10487-10495, 1999 Nov 17.   View Abstract

Belcher WJ, Breede M, Brothers PJ and Rickard CEF   A PORPHYRIN AS A BINUCLEATING LIGAND - PREPARATION AND CRYSTAL STRUCTURE OF A PORPHYRIN COMPLEX CONTAINING A COORDINATED B2O2 RING.   Angewandte Chemie (International Edition in English). 37(8):1112-1114, 1998 May 4.  

Tonei DM, Baker LJ, Brothers PJ, Clark GR and Ware DC   Decarboxylation of an alpha-amino acid coordinated to cobalt(III): kinetic stabilisation and molecular structure of a Co-C-N three-membered ring incorporated into a cobalt(III) macrocyclic ligand complex.   Chemical Communications. (23):2593-2594, 1998 Dec 7.   View Abstract

Ware DC, Palmer HR, Pruijn FB, Anderson RE, Brothers PJ, Denny WA and Wilson WR   BIS(DIALKYL)DITHIOCARBAMATO COBALT(III) COMPLEXES OF BIDENTATE NITROGEN MUSTARDS - SYNTHESIS, REDUCTION CHEMISTRY AND BIOLOGICAL EVALUATION AS HYPOXIA-SELECTIVE CYTOTOXINS.   Anti-Cancer Drug Design. 13(2):81-103, 1998 Mar.   View Abstract

Belcher WJ, Brothers PJ and Rickard CEF   BIS(PROPIONATO-O)[5,10,15,20-TETRA(P-CHLOROPHENYL)PORPHYRINATO-KAPPA-N-4]TIN(IV) DICHLOROMETHANE SOLVATE.   Acta Crystallographica - Section C - Crystal Structure Communications. 53(Part 6):725-726, 1997 Jun 15.   View Abstract

Brothers PJ, Clark GR, Palmer HR and Ware DC   CONDENSATION REACTIONS OF COBALT AMINO ACID COMPLEXES WITH FORMALDEHYDE - PREPARATION AND CRYSTAL STRUCTURES OF COBALT COMPLEXES CONTAINING NEW HEXADENTATE, PENDANT-ARM MACROCYCLIC AND ACYCLIC LIGANDS.   Inorganic Chemistry. 36(24):5470-5477, 1997 Nov 19.   View Abstract

Brothers PJ, Rickard CEF, Strange CM and Ware DC   TWO NEW TRIPODAL LIGANDS WITH AN N4S3 DONOR SET - THE X-RAY CRYSTAL STRUCTURE OF 4,4',4''-[NITRILOTRIS(ETHYLENEIMINO)]TRIS(PENT-3-ENE-2-THIONE).   Australian Journal of Chemistry. 50(4):373-378, 1997.   View Abstract

Craig PR, Clark GR, Palmer BD, Brothers PJ, Denny WA and Ware DC   MONO- AND BIDENTATE COORDINATION OF N,N-DIALKYLATED 1,3-PROPANEDIAMINES TO COBALT(III) - A STRUCTURAL AND SPECTROSCOPIC STUDY.   Inorganica Chimica Acta. 260(1):43-52, 1997 Jul 15.   View Abstract

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Teaching

Course		Role
CHEM 220	Inorganic Compounds Structure, Bonding and Reactivity	Coordinator
CHEM 701	PG Topics in Chemistry 1	Coordinator
CHEM 702	PG Topics in Chemistry 2	Coordinator
CHEM 793	BSc(Hons) Dissertation in Chemistry	Coordinator