Preparation and linear/nonlinear optical properties of a gold-terpyridine nanohybrid constructed through thiocyanate coordinating bridge

Abstract In this study, a gold-based nanohybrid was designed and prepared, which was constructed through interfacial coordination interaction between gold nanoparticals (Au NPs) and terpyridine-Zn (II) complexes (L-Zn(NCS)2, L = N,N-diphenyl-4-(2,2':6′,2″-tepyridin-4-yl)aniline) with thiocyanate unit as the coordination bridge. The optimized molar ratio of L-Zn(NCS)2 to chloroauric acid was selected as 1:15 through UV-vis absorption spectra. Compared with that of pure Au NPs or free L-Zn(NCS)2, the electron absorption of the nanohybrid was enhanced and the single photon excited fluorescence was weakened. Enhanced nonlinear optical properties and enlarged two-photon absorption cross section (δTPA = 21870.56 GM) were also captured. Furthermore, the nanohybrid exhibited excellent photothermal conversion performance, which was beneficial to be applied in phototherapy against living cancer cells. HeLa cells co-cultivated with the nanohybrid were gradually apoptotic within 10 min irradiation at 860 nm.