|
Prof HM Marques, Dr AS de Sousa, Dr CB Perry
The research interests of this group focus on the inorganic chemistry of biological systems with particular emphasis on the chemistry of cobalt, iron and the lanthanides.
 Work in progress includes
______________________________________________________________
Exploring the kinetic lability of Co(III) in vitamin B12 systems
The synthesis and molecular modelling of metalloporphyrins
Macrocyclic chemistry focussing on structural features in ligand architecture that can be used to alter ligand selectivity towards metal ions.
Porphyrins are widely distributed in nature where they perform an almost bewildering variety of function. This is a strong indication that the fundamental properties of the porphyrin can be controlled and modified by a protein. Delineating how nature utilise a limited number of metal cofactors and the twenty-odd amino acids that constitute proteins, and manipulates the fundamental chemical properties of the metal ion to coerce diverse behaviour is one of the questions we are exploring.
The cobalamins are biologically related to the porphyrins and two organometallic species, methylcobalamin and adenosylcobalamin (coenzyme B12) function as cofactors for enzymatic reactions. That Co(III), which is the classic example of a hard, inert, d6 metal ion, is used by nature as a catalyst (but only in combination with the macrocycle corrin) is witness to nature s ability to manipulate fundamental chemical properties of metal ions. What aspects of the corrin macrocycle are responsible for this remarkable manipulation of Co(III) chemistry, for conferring on this normally inert metal ion such astonishing lability?
The idea of synthesising organic molecules with a predisposition for the encapsulation of metal ions has given rise to rewarding research endeavours in various fields of chemistry. We are interested in the design of new lanthanide metal complexes with macrocyclic and acyclic chelating ligands as suitable contrast agents in magnetic resonance imaging (MRI) or as luminescent devices in biomedical applications.Work in progress explores the grafting of aliphatic groups onto the backbone of the pendent moieties of macrocyclic ligands in order to tune the selectivity of the ligand towards the metal ion of choice, as well as altering the substitution kinetics of coordinated water molecules at the metal site. These are both crucial parameters in developing an MRI agent. The chelating agents under investigation may also prove to be useful in other areas. They may be excellent chelating agents for radionuclides and hence prove to be useful chelates for radiopharmaceuticals used in nuclear medicine. Also these chelating agents, behaving as luminescent probes, can be used for diagnostic applications such as the detection of microdamage in bone.
|
