1. Graduate School for Integrative Sciences & Engineering (NGS); National University of Singapore; 28 Medical Drive 117456 Singapore Singapore
2. Department of Chemistry; National University of Singapore; 3 Science Drive 3 117543 Singapore Singapore
3. National University of Singapore (Suzhou) Research Institute; 377 Lin Quan Street, Suzhou Industrial Park Suzhou Jiangsu 215123 P. R. China
4. Department of chemistry; Zhejiang Sci-Tech University; Hangzhou Zhejiang 310018 P. R. China
5. Chemistry Department; King Fahd University of Petroleum and Materials; Dhahran 31261 Saudi Arabia