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Professor G.M. Watkins

Professor G.M. Watkins BSc(Hons); PhD (University of Cape Town); MSACI
Associate Professor of Inorganic Chemistry & 3rd Year Course Coordinator

 

TEACHING

    : current


1st Year: Chemical & physical equilibria

3rd Year: Coordination compounds & transition metal chemistry: Theoretical aspects, application in magnetism and spectroscopy

Honours Year: Group theory;

                      Advanced applied vibrational spectroscopy;

                      Inorganic reaction mechanisms.

    : previous

2nd Year: Foundational Chemical Principles: Periodic trends of the main group elements

 

 RESEARCH INTERESTS


“Thermal and spectroscopic studies of transition metal complexes & applied chemical technology”.
As a physical inorganic chemist, my areas of interest are molecular spectroscopy, coordination chemistry and bioinorganic chemistry, applied to areas such as nanotechnology, medicinal and industrial uses. The group works with nmr, infrared and Raman spectroscopy, UV-visible spectroscopy, XRD(P), thermal analysis (TG, DSC and TG-FTIR) BET and molecular modelling.  The group currently consists of six PhD, three MSc and two Honours students.
Current Research Areas:


1. Nanomaterials: Metal Organic Framework materials (MOF’s);
MOFs may be formed in the crystalline phase by the self- assembly of structurally defined molecular modules possessing translational symmetry of one or more dimensionality. Such open framed network nano-materials have a wide variety of structural diversity and are expected to exhibit novel properties such as inclusion behaviour.   This behaviour has application in two areas of interest; in environmental applications and in separation science. In the area of environmental impact, there are two foci for MOFs relating to the adsorption of hydrogen, and of carbon monoxide. Currently MOFs are the only materials that meet the US Department of Energy targets for hydrogen storage devices, but at present at economically unfavourable pressure and temperature conditions.  Certain MOFs have also been shown to have carbon dioxide adsorption characteristics double that of current commercial absorbers. Alternate MOFs are under investigation to identify candidates with better gas adsorption characteristics and selectivity for separation science.


2. Bioinorganic metal complexes
Metal Schiff base complexes have recently been shown to demonstrate antiplasmodial activity; the proposed activity of octahedral metal complexes containing N4O2 donors thought to occur by steric inhibition of haemozoin formation, thereby preventing the biomineralisation of the haeme which is toxic to the parasite. An alternative mechanism proposed for the antimalarial activity of four coordinate copper(II) complexes is the facile reduction to the cuprous species with subsequent activation of intracellular oxygen. Both mechanisms are targets of approach in this antimalarial study. This project involves the synthesis, characterization and in vitro and in vivo biological evaluation screening of different classes of Co(II), Co(III), Ni(II) and Cu(II) complexes with ligands containing ONO, ONS or NNS as donor atoms. Key biological techniques for the proposed study involve the use of antimicrobial bioassay, cell proliferation assays and antiplasmodial assays. 


3. Ligand isotope studies of transition metal complexes.
Isotopic labelling of ligands is an important tool in identifying vibrational spectroscopic interactions within metal complexes; it is essential in vibrational analysis, and may provide relevant information in determining reaction mechanisms, amongst other things. These studies are allied with molecular modelling (DFT, CPMD, etc.)


Past Postgraduate Students:

PhD:

  • Dr N.P. Magwa. “The development of amine-based extractants for separation of base metals in a sulfate medium.”(2015) (Co-supervisor)
  • Dr. T.E.  Olalekan. “Synthesis, Characterisation and biological activity of 2-(methylthiomethyl) anilines, 2-(methylthio)anilines, their Schiff base derivatives and Metal(II) (Co, Ni, Cu) complexes” (2013) 
  • Dr. A.O. Sobola. “Synthesis, characterisation and antimicrobial activity of Cu(II) complexes of some hydroxybenzaldimines and their derivatives.” (2012) 
  • Dr. R.O. Shaibu. “A bioinorganic study of some cobalt(II) complexes of variously substituted hydroxybenzaldimines.” (2008)
  • Dr. E. Lamprecht. “Thermal, spectroscopic and X-ray diffraction studies of copper(II) 1, 2, 4, 5- benzenetetracarboxylates and copper(II) oxalate: A study of metal-organic frameworks.”( 2008) 
  • Dr.  J.J. Guthrie Strachan. “The investigation, development and characterisation of novel zirconium-based tanning agents.” (2006) 
  • Dr. A. Dairam. “An investigation into the neuroprotective properties of the non-steroidal anti-inflammatory agent tolmetin, sulindac and tumeric.” (2006)(Co-supervisor). 
  • Dr. G.J.M. Medina. “Ligand isotope vibrational spectroscopic and DFT studies of Pt(II) & Cu(I) complexes.”  (2005)  
  • Dr. A.P.M. Antunes. “Removal and recovery of Gold and Platinum from aqueous solutions utilizing the non-viable biomass Azolla filiculoides.” (2002)(Joint supervisor).

MSc:

  • Mr W. Moloto.“A bulk and fraction-specific geochemical study of the origin of diverse high-grade hematitic iton ores from the Transvaal Supergroup, Northern Cape Province, South Africa.” (2017) (Co-supervisor)
  • Mr W. Feldmann. “Study into the Synthesis, Characterisation and Applications of Vanadium-based Metal Organic Frameworks, using 1, 2, 4, 5-Benzenetetracarboxylic acid.” (2016)
  • Mr. M.J. Coombes  “A Comparative Study  of Two  Copper(II) Based Metal-Organic Frameworks:  Cu2¼(OH)½B4C•8H2O and Cu2Na(OH)B4C•7H2O” (2013(Distinction)
  • Mr. C.A. Makanjee “An experimental and theoretical investigation of unstable Fischer chromium carbine complexes.” (2013) (Co-supervisor)
  • Ms. N.P. Magwa “A spectroscopic study of the electronic effects on copper(II) and copper(I) complexes of ligands derived from variously substituted benzaldehyde- and cinnamaldehyde-based Schiff bases.” (2010)
  • Ms. E. Mopp “An bioinorganic investigation of some metal complexes of the Schiff base N,N’-bis(3-methoxysalicylaldimine)propan-2-ol.” (2010)

PUBLICATIONS:

  •  “Spectroscopic, structural and theoretical studies of copper(II) complexes  of tridentate NOS Schiff bases” Temitope E. Olalekan, Adeniyi S. Ogunlaja , Bernardus Van Brecht , Gareth M. Watkins Journal of Molecular Structure. (2016) 1122, Pages 72–79. http://dx.doi.org/10.1016/j.molstruc.2016.05.098
  •  “Dimethylammonium 2,4,5-tricarboxybenzoate. An example of the decarbonylation of N,N-dimethylformamide in the presence of a metal and a benzenepolycarboxylic acid. Is zirconium(IV) the Tsotsi?” S. T.  Hulushe, E. C. Hosten and G. M. Watkins Acta Cryst. E Research Communications (2016). E72. 1521-1525.
  • “Sorption of trioctyl amine to kaolinite.” F Moyo, R Tandlich, P Madikizela, E Chifunda and GM Watkins Fresenius Environmental Bulletin, (2016) 25 (1), 78-88.
  •  “Synthesis, Structure and Theoretical Studies of  bis(pentacoordinated) μ-o-[CuL2]2: Predicting Distortion towards Trigonality.” A.O. Sobola, G.M Watkins, B. Van Brecht and I.A. Adejoro. J. Coord. Chem. (2016) 69(1), 81-89 DOI:    10.1080/00958972.2015.1110853.
  •  “Synthesis And Spectroscopic Studies Of Schiff Bases From Variously Substituted Benzaldhydes And 2-Aminomethyl Pyridine.” Rafiu O Shaibu and Gareth M Watkins. Ife Journal of Science (2015) 17(1)31-39.
  •  “Crystal structures, spectroscopic and theoretical studies of novel Schiff bases of 2-(methylthiomethyl) anilines” by Temitope Elizabeth Olalekan, Isaiah Adejoro, Bernardus Van Brecht and Gareth Mostyn Watkins. Spectrochim Acta A, (2015) 139, 385-395.
  • “Copper(II) complexes of 2-(methylthiomethyl)anilines: Spectral, structural properties and in vitro antimicrobial activity," by Temitope Elizabeth Olalekan, Denzil Ronald Beukes, Bernardus Van Brecht and Gareth Mostyn Watkins  Journal of Inorganic Chemistry, (2014), 2014, Article ID 769573, 10 pages http://dx.doi.org/10.1155/2014/769573
  • “Synthesis, Characterisation and antimicrobial activity of Copper(II) complexes of some o-substituted aniline Schiff bases; Crystal structure of bis(2-methoxy-6-imino)methylphenol copper(II) complex”     AO Sobola, GM Watkins and B van Brecht. South African Journal of Chemistry (2014) 67, 45-51  ( ISSN 03794350)
  • “Antimicrobial activity and Cu(II) complexes of Schiff bases derived from ortho-aminophenol and salicylaldehyde derivatives” Abdullahi Owolabi Sobola and Gareth Mostyn Watkins Journal of Chemical and Pharmaceutical Research, 2013, 5(10):147-154 (ISSN : 0975-7384 CODEN(USA) : JCPRC5)
  • “The coordination and extractive chemistry of the later 3d transition metals with bis((1R-benzimidazol-2-yl)methyl)sulphide” N. Magwa, E. Horsten, G.M Watkins and Z. R. Tshentu   Journal of Coordination Chemistry Vol. 66, No. 1, 10 January 2013, 114–125(DOI:  10.1080/00958972.2012.748192)
  • “An Exploratory Study of Tridentate Amine Extractants: Solvent Extraction and Coordination Chemistry of Base Metals with Bis((1R-benzimidazol-2-yl)methyl)amine” N. Magwa, E. Horsten, G.M Watkins and Z. R. Tshentu International Journal of Nonferrous Metallurgy, 1 (2012) 49-58.
  •  "Introducing Chemistry Students to the "Real World" of Chemistry" Michael E. Brown, Ronald C. Cosser, Michael T. Davies-Coleman, Perry T. Kaye, Rosalyn Klein, Emmanuel Lamprecht, Kevin Lobb, Tebello Nyokong, Joyce D. Sewry, Zenixole R. Tshentu, Tino van der Zeyde, and Gareth M. Watkins. J. Chemical Education, 87 (2010) 500-3.
  •  “Designer ligands. Part 15. Synthesis and characterisation of Novel Mn(II), Ni(II) and Zn(II) complexes of 1, 10 phenathroline-derived ligands” K.W. Wellington, P.T. Kaye and  G.M. Watkins, ARKIVOC, xiv (2009) 301-313.
  • ““Designer ligands. Part 14. Novel Mn(II), Ni(II) and Zn(II) complexes of benzamide- and  biphenyl-derived ligands” K.W. Wellington, P.T. Kaye and  G.M. Watkins, ARKIVOC, xvii (2008) 248-264.
  • Curcuminoids,  curcumin and demethoxycurcumin, reduce lead (Pb) induced memory deficits in male Wistar  rats.” A. Dairam, J.L. Limson G.M. Watkins, E. Antunes and S. Daya, J. Agri.  Food Chem. 55 (2007) 1039-44.
  • “Thermal decomposition of copper(II) oxalate revisited.” E. Lamprecht, G.M. Watkins and M.E. Brown. Thermochim. Acta, 446 (2006) 91-100.
  • “Designer Ligands. Part 13. Synthesis and catalytic activity of transition metal complexes of a multidentate macrocyclic ligand.”  Perry T. Kaye, Gareth M. Watkins and Kevin W. Wellington,  S. Af. J. Chem., 58 (2005), 1-3.
  •  “100 years of chemistry at Rhodes University.”  Brown, M.E. and Eve, D.J. and Kaye, Perry T. , Rivett, D.E.A. and Watkins, G.M. South African Journal of Science, 100  (2004) 530-538
  •  “Designer Ligands. Part 9. Catalytic activity of biomimetic copper(II) and cobalt(II) complexes of multidentate ligands. ”  Perry T. Kaye, Tebello Nyokong, Gareth M. Watkins and Kevin W. Wellington, ARKIVOC, 9 (2002)  9 - 18.
  • "Through metal binding curcumin protects against lead- and cadmium-induced lipid peroxidation in rat brain homogenates and against lead-induced tissue damage in rat brain." S.Daniel, J.L. Limson, A. Dairam, G.M. Watkins and S. Daya, J. Inorg. Biochem., 98 (2004) 266-275.
  • “The removal of Gold from aqueous solution by the viable microbial biomass Phoma sp.” A.P.M. Antunes J.R. Duncan  , G. M. Watkins and A. Maclear,, Res. & Environ. Biotech. 3 (2002) 219-228.
  • "Batch studies on the removal of Gold(III) from aqueous solution by Azolla filiculoides. ”  A.P.M. Antunes, G. M. Watkins and J.R. Duncan, Biotech. Letters, 23 (2001) 249-251.
  • . "Thermal and structural studies of amide complexes of transition metal(II) chlorides. I: Stoichiometry."  A.N. Nelwamondo, D.J. Eve, G.M. Watkins and M.E. Brown, Thermochimica Acta, 318 (1998) 165-175.
  • "The infrared spectra of the square planar rhodium(I) complexes cis-[Rh(CO)2(pyridine)(X)](X = Cl, Br).  Isotopic labelling studies and normal co-ordinate analysis."  P.S. Hall, G.E. Jackson, J.R. Moss, D.A. Thornton, P.F.M. Verhoeven and G.M. Watkins,  Spectrosc. Letters, 26 (1993) 1247-1267. 
  • "Vibrational conformational-analysis of methyl fluoroacetate and methyl difluoroacetate."  B.J. Van der Veken, S. Truyens, W.A. Herrebou and G. Watkins, J. Mol. Struct., 293 (1993) 55-58. 
  • "The infrared spectra (4000 - 50 cm-1) of quinoline N-oxide and its perdeuterated analogue with metal(II) perchlorates of the first transition series."  D.A. Thornton and G.M. Watkins,  J. Coord. Chem., 29 (1993) 45-56.
  • "The limitations to employing the vibrational assignment notation of an aromatic homocycle to its heterocyclic analogues."  D.A. Thornton and G.M. Watkins,  Spectrosc. Letters, 26 (1993) 887-895.
  • "The infrared, nmr (1H, 13C) and electronic spectra of the complexes cis-[Rh(CO)2(pyridine N-oxide)(X)](X = Cl, Br)."  P.S. Hall, G.E. Jackson, J.R. Moss, D.A. Thornton and G.M. Watkins,  J. Alloys and Compounds, 197 (1993) 67-74. 
  • "Ligand isotope studies of Zeise's salt derivatives (and their CO analogues) with some aza-heterocycles and their N-oxides. II.  Their preparation, characterization and use in developing 1H nmr and infrared spectra as a diagnostic tool."  P.S. Hall, G.A. Foulds, D.A. Thornton and G.M. Watkins,  Spectrochim. Acta, 48A (1992) 597-604. 
  • "An assessment of the assignment of characteristic N-O vibrations in aromatic N-oxides."  D.A. Thornton and G.M. Watkins, Spectrosc. Letters, 25 (1992) 1023-1036. 
  • "Ligand isotope studies of Zeise's salt derivatives (and their CO analogues) with some aza-heterocycles and their N-oxides. I.  Full infrared spectral assignments (4000 - 50 cm-1)."  G.A. Foulds, D.A. Thornton and G.M. Watkins,  Spectrochim. Acta, 48A (1992) 577-596.
  • "The infrared spectra (4000 - 50 cm-1) of 2,2'-bipyridine N,N'-dioxide and its perdeuterated analogue with metal(II) perchlorates of the first transition series."  D.A. Thornton and G.M. Watkins,  J. Coord. Chem., 25 (1992) 317-326.
  • "The infrared spectra (4000 - 50 cm-1) of 2,2'-bipyridine, 1,10-phenanthroline and their perdeuterated analogues with metal(II) perchlorates of the first transition series."  D.A. Thornton and G.M. Watkins,  J. Coord. Chem., 25 (1992) 299-315. 
  • "A full vibrational assignment (4000 - 50 cm-1) of 1,10-phenanthroline and its perdeuterated analogue."  D.A. Thornton and G.M. Watkins,  Spectrochim. Acta, 47A (1991) 1085-1096. 
  • "Isotopic labelling studies of some aromatic N-oxides IV.  A full vibrational assignment of the infrared spectra (4000 -50 cm-1) of quinoline N-oxide  dihydrate and its fully deuterated analogue."  D.A. Thornton and G.M. Watkins,  Bull. Chim. Soc. Belg., 100 (1991) 235-245. . 
  • "Isotopic labelling studies of some aromatic N-oxides III.  A full vibrational assignment of the infrared spectra (4000 - 50 cm-1) of 2,2'-bipyridine N,N'-dioxide and its fully deuterated analogue."  D.A. Thornton and G.M. Watkins,  Bull. Chim. Soc. Belg., 100 (1991) 221-234. 
  • "Isotopic labelling studies of some aromatic N-oxides II.  A full vibrational assignment of the infrared and Raman spectra (4000 - 50 cm-1) of pyrazine N-oxide and its fully deuterated analogue."  D.A. Thornton, P.F. Verhoeven, G.M. Watkins, H.O. Desseyn and B.J. van der Veken,  Bull. Chim. Soc. Belg., 100 (1991) 211-220.
  • "The infrared spectra of ethylenediamine complexes IITris-, bis- and mono-(ethylenediamine) complexes of metal(II) halides."  A.M.A. Bennett, G.A. Foulds, D.A. Thornton and  G.M. Watkins,  Spectrochim. Acta, 46A (1990) 13-22.
  • "Isotopic labelling studies of some aromatic N-oxides I.  A full vibrational assignment of the infrared and Raman spectra (4000 - 50 cm-1) of pyrazine N,N'-dioxide and its fully deuterated analogue."  D.A. Thornton, P.F. Verhoeven, G.M. Watkins, H.O. Desseyn and B.J. van der Veken,  Spectrochim. Acta, 46A (1990) 1439-1451.
  • "A re-examination of the infrared spectra of first transition series metal(II) and metal(III) tropolonates."  K.J. Burden, D.A. Thornton and G.M. Watkins,  Spectrochim. Acta, 45A (1989) 1179-1186.
  • A double isotopic labelling study of the infrared spectra of the linkage isomers [Pd(bipy)(SCN)2], [Pd(bipy)(NCS)2] and related complexes."  C. Engelter, D.A. Thornton and G.M. Watkins,  Spectrosc. Letters, 22 (1989) 935-944.
  •   Cisplatin.  Synthesis of some 2,3-diaminopropionic ester analogues: dichloro(hexadecyl 2,3- diaminoproprionato) platinum(II) and dichloro(cyclohexyl 2,3- diaminoproprionato) platinum(II)."  D.B. Firfiray, R.G.F. Giles, D.A. Thornton, G.M. Watkins, G.C. Yorke, A. Becker and R.R. Levitt, S. Afr. J. Chem., 40 (1987) 149-150.  
  •  "The infrared spectra of complexes of variously substituted anilines with platinum(II) halides."  T.P.E. Auf der Heyde, G.A. Foulds, D.A. Thornton and G.M. Watkins,  Spectrosc. Letters, 14 (1981) 455-462.
  • "The infrared spectra of aniline complexes of platinum(II) halides and nitrite."  T.P.E. Auf der Heyde, G.A. Foulds, D.A. Thornton and G.M. Watkins,  J. Molec. Struct., 77 (1981) 19-24.
  • "The infrared spectra (600 - 150 cm-1) of pyridine N-oxide complexes of metal(II) halides and mixed-ligand (pyridine N-oxide / dimethylsulphoxide) complexes of copper(II) halides."  T.P.E. Auf der Heyde, C.S. Green, D.E. Needham, D.A. Thornton and G.M. Watkins,  J. Molec. Struct., 70 (1981) 121-126. 

Contact Information:
Telephone: +27 46 603 8923
Fax: +27 46 622 5109
Secretary: +27 46 603 8254
Email: g.watkins@ru.ac.za

Postal Address:
Department of Chemistry
Chemical and Pharmaceutical Sciences Building
Corner of University and Artillery Roads
Grahamstown
6140   

Courier Address:
Department of Chemistry
Cnr of University and Artillery Roads
Rhodes University
Grahamstown
6140
South Africa

Last Modified :Tue, 08 Aug 2017 14:22:58 SAST