1. State Key Laboratory of Medicinal Chemical biology College of Chemistry Nankai University Tianjin 300071 China
2. Department of Chemistry University of South Florida 4202 East Fowler Avenue Tampa FL 33620 USA
3. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center Frontiers Science Center for New Organic Matter Nankai University Tianjin 300071 China