1. Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan
2. Department of Chemistry, Liverpool University, Liverpool, L69 7ZD, U.K., LE11
3TU, U.K.
3. Department of chemistry,
Faculty
of Science, University of Malaya, Kuala
Lumpur-50600, Malaysia
4. School of Chemistry and Materials
Science Centre, The University of Manchester, Oxford Road, Manchester, M13 9PL U.K.