1. Section of Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
2. Aristotle University of Thessaloniki, Faculty of Chemistry, Inorganic Chemistry Laboratory, P. O. Box 135, 54124 Thessaloniki, Greece
3. School of Pharmacy, The Robert Gordon University, Schoolhill, Aberdeen AB10 1FR, Scotland