Synthesis and characterization of amphiphilic triazole ligand and its complex for potential application in phosphorescent temperature sensor materials

Abstract

Phosphorescent materials have attracted much attention due to their promising applications in sensors, display, and optical imaging. Extensive studies have reported on trinuclear gold (I) complexes such as imidazolate, pyrazolate and carbeniete ; however, triazolate is rarely reported. Although hydrophobic trinuclear gold (I) triazolate complex has been reported in a solid state with luminescence center at near infrared area (750 nm) at room temperature, but no example of phosphorescent amphiphilic trinuclear gold (I) triazolate complex with liquid crystalline properties has been reported for potential application in near infrared phosphorescent temperature sensor materials. Here we report the synthesis of triazole ligand bearing amphiphilic side chain and then use it for complexation with gold salt to form amphiphilic trinuclear gold (I) triazolate complex. Triazole ligand was prepared in six stepwise reactions from triethylene glycol (EG3) to tosilate ethylene glycol (TsEG3,step 1; 180g, 90%), mono substitution triethylene glycol with decanediol (C10EG3OH, step 2; 17g, 43%), bromination (C10EG3Br, step 3; 9g, 45%), Williamson ether substitution reaction (C10EG3BnCOOMe,step 4; 3.5g, 67%), carboxylation (C10EG3COOH,step 5; 2g, 80%) and amidation (C10EG3TzH,step 6; 240mg, 23%). The resulting triazole ligand will be reacted with dimethylsulfide gold (I) chloride ([Au(SMe2]Cl) in methanol in the presence of excess freshly distilled triethylamine (Et3N) to form the gold complex. The phosphorescent properties will be discussed later.