The particles were prepared in a one-step synthesis at room temperature. Briefly, 1 ml of 25 mM of an aqueous solution of the chloroauric acid was placed in a glass vial, and the pH was first adjusted by addition of 150 μL of 0.5 M NaOH. Finally, different volumes of 1% aqueous solution of sodium citrate (Na3Cit, 250, 700, and 1000 μL) were then added and mixed for 5 minutes. The solution was left undisturbed for 1 hour till the color changed from yellow to gray and finally dark black, confirming the reduction process. The gold particles were washed with deionized water and separated by centrifugation (6000 rpm, 12 min). The nanowires were then dispersed in an equal volume of deionized water for further use. To compare the plasmonic activity towards the crosslinking of the diazonium molecules, gold nanoparticles known as gold nanoflowers (AuNFs) and silver nanoparticles (AgNPs) have been prepared according to our recent published protocols and used as plasmonic substrates for the reaction. SERS substrate. Before the Raman measurements, the silicon substrate was cleaned in a solution of 30 wt % H2O2and 30 wt % H2SO4. The substrate was then washed with deionized water and ethanol. Afterward, 50 μl of the gold solution was placed on the cleaned substrate and dried before being used. The gold nanowires assembled on the substrate were immersed in 5 mM ethanolic solution of N2TP + BF4 -for 1 h. The sample was washed with ethanol to remove the unattached molecules and dried before being measured.