1. École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR-UMR 6226, Université de Rennes, F-35000 Rennes, France
2. College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, P. R. China
3. Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden