1. Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
2. Division of Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
3. Department of Chemistry and Nanomaterials Science, Bogdan Khmelnitsky National University, Cherkasy 18031, Ukraine
4. College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, P. R. China