1. State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology, Zhongshan Road 158-46, 116012 Dalian, People's Republic of China, and Center of Molecular Devices, Department of Chemistry, Physical Chemistry, and Center of Molecular Devices, Department of Chemistry, Organic Chemistry, Royal Institute of Technology (KTH), Teknikringen 30, 10044 Stockholm, Sweden