^a Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
E-mail: berg@mail.chem.sc.edu
Tel: +1-803-777-1514

^b Department of Chemistry, Ohio State University, Columbus, USA
E-mail: coleman@chemistry.ohio-state.edu
Fax: +1-614-292-1685
Tel: +1-614-292-4548

^c Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
E-mail: murphy@mail.chem.sc.edu
Fax: +1-803-777-9521
Tel: 803-777-3628