1. State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian 116012, P. R. China, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden, KTH School of Chemical Science and Engineering, Department of Chemistry, Organic Chemistry, Royal Institute of Technology (KTH), 10044 Stockholm, Sweden