[1] UCL, Fac Math & Phys Sci, Dept Chem, London WC1E 6BT, England
[2] Univ Nigeria, Dept Pure & Ind Chem, Nsukka 410001, Nigeria
[3] Univ Canterbury, Sch Phys & Chem Sci, Dept Chem, Christchurch 8040, New Zealand
[4] Univ Canterbury, Dept Chem & Proc Engn, Christchurch 8040, New Zealand
[5] Alex Ekwueme Fed Univ Ndufu Ailke, Dept Biotechnol, PMB1010, Ikwo, Nigeria