Rapid Induced Aggregation of Gold Nanoparticles by Diolefinic Dyes

Rapid Induced Aggregation of Gold Nanoparticles by Diolefinic Dyes

Aggregation kinetics of gold nanoparticles (Au NPs) interaction in the presence of some diolefinic dyes, namely 1,4-bis (β-pyridyl-2-vinyl) benzene (P2VB), 1,4 bis(2-methylstyryl) benzene (MSB) and 2,5 distyrylpyrazine (DSP), were studied in methanol using steady state UV-Vis spectrophotometry and stopped-flow spectrophotometry. All three dyes induced the aggregation of Au NPs, but with different rates. The rate of interaction of P2VB and MSB with Au NPs were in time-scale of milliseconds, 6 ms-1 and 3.25 ms-1, respectively, while the interaction between DSP and Au NPs occurred in time-scale of minutes. The rates of interaction between Au NPs and these dyes go in the order of P2VB > MSB » DSP. The density functional theory (CAM-B3LYP) predicted that the dye with higher group charge on the terminal moieties possess higher affinity toward the aggregation as it strengthen its electrostatic interactions with the citrate-capped Au NPs.