Ishenkumba A. Kahwa

Deputy Principal
B.Sc.(Hons.), M.Sc., Dar es Salam, Ph.D., Louisiana

Research Interests
We have research interest in polynuclear compounds of lanthanide(III), p- and d-block ions with potential biomedical, extractive metallurgical and catalytic applications. Their preparation, structures and luminescence spectroscopy and decay dynamics as well as electron paramagnetic resonance behavior are the main focus. Lasers ( 1J YAG and 1 mJ nitrogen and their matching dye lasers) along with a helium refrigerator, luminescence spectrometer and accompanying electronics are the major instrumentation. Ligands of interest are aromatic Schiff's bases, crown ethers, phthalamates and alkylamine dendrimers and their derivatives.We also have interests in solid waste and environmental pollution, especially asbestos waste. Waste disposal, polluted sites, their public health effects and policy issues are of interest.
 
Research in the Kahwa group is in the general areas of  inorganic chemistry, with an emphasis on the creation of new coordination compounds. The long-term goal of the programme is to develop new materials for nano devices and for application in bio-medicine and catalysis.
 
Generally, the group prepares and characterises new compounds of  rare earths, transition metals and S and P block elements. A phenomenon of interest has been the clustering of metal species and the  interactions arising therefrom or responsible for the aggregation. Metal-metal and other interactions are probed using a variety of lasers and equipment capable of probing temperature-dependent phenomena  between 8K and 400K. 
 
The current focus is on rare earth elements, transition metals, S and P block elements and the metal-metal interactions within their clusters. The aim is to decide the cluster materials needed, how they should be structured and who the neighbours should be for them to be effectively assembled. Studies are underway towards developing the chemical glues needed to bind the metals in the clusters together to maximise the applications in biomedical diagnostics and therapeutics.
 
The approach is exploratory, and the primary research tools used include X-ray diffraction machines and tunable laser sources, as well as NMR and luminescence spectrometers.
 
As a minor research interest, the group delves into environmental issues, especially those involving toxic or hazardous materials such as asbestos and mold. Public policies related to science, technology and innovation are also of interest.
 
Prof. Kahwa has published approximately 70 journal articles on his research, most of which are well cited
 
Selected Publications
    I A Kahwa, C.A.Duncan, E.P.Copeland, A.Quick, D.J.Williams, "Unusual formation and crystal structure of a new stable dinuclear vanadium (V) amino-imino-acetal". Journal of the Chemical Society, Dalton Transactions 1997, 917.

  •     I A Kahwa, E P Copeland, J.T.Mague and G.L.McPherson, "A novel mixed-valence vanadium(IV/V) molecule exhibiting unusual electron delocalization over the [V2O3]3+ core", Journal of the Chemical Society, Dalton Transactions, 1997, 2849.
  •     I A Kahwa, N.F.Fender, F.R.Fronczek, V.John, and G.L.McPherson, "The preparation, structures and unusual luminescence characteristics of supramolecular [(A18C6)4MBr4] [TlBr4]2(A = Rb,K; M = Mn, Zn) complexes", Inorganic Chemistry 1997, 37, 5539.
  •     I A Kahwa, D.M.Y. Barrett, B. Radüchel, A.J.P.White and D.J.Williams, "Hydrolytic products of diphthalimidodiethylamine and temperature independent sensitized luminescence of their lanthanide(III) complexes", Journal of the Chemical Society, Perkin Transactions 2, 1998, 1851.
  •    I A Kahwa, A.S. Gajadhar-Plummer, A.J.P.White and D.J.Williams, "Chemistry of rare earth hypoco-ordinated cluster cations: Formation of novel oxoacetate clusters", Inorganica Chimica Acta 1998, 281, 201.
  •     I A Kahwa, H.O.N.Reid, A.J.P.White and D.J.Williams, "Intense photosensitized emission from stoichiometric compounds featuring Mn2+ in seven and eight coordination environments", Inorganic Chemistry 1998, 37, 386.
  •      I A Kahwa, R.C.Howell, K.V.N.Spence, and D.J.Williams, " Structure and luminescence of the neutral dinuclear lanthanide(III) complexes [Ln(api)]2", Journal of the Chemical Society, Dalton Transactions 1998, 2727.
  •     I A Kahwa, N.S.Fender, A.J.P. White and D.J.Williams, "Extraordinary bromide anion templated self assembly of the [(Na(15C5))4Br]3- trication", Journal of the Chemical Society, Dalton Transactions 1998, 1729.
  •     I A Kahwa, D.M.Y.Barrett, and J.T.Mague, "One pot atmospheric carbon dioxide fixation and nitrate anion inclusion in cylindrical micropores of resulting lanthanide(III) oxalates", New Journal of Chemistry 1998, 919.