1. Tianjin Key Laboratory of Structure and Performance for Functional MoleculesKey Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry (Ministry of Education)College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
2. Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University 21 Nanyang Link 637371 Singapore Singapore