Surface Enhancement Raman Spectroscopy And Density Functional Theory Study Of Silver Nanoparticles Synthetized With D-Glucose

The role of alpha- and beta-d-glucose, and d-gluconate anion, acting as capping agent, on silver nanoparticles (AgNPs) was evaluated using both Raman and density functional theory studies. The particles were synthetized employing glucose, as reducing and blocking agent, in alkaline conditions. Capping agents were characterized through surface enhancement Raman spectroscopy together with modeling performed using silver clusters. Several geometries were optimized, and its energies and wavenumbers were calculated for each of them. Vibration normal modes from d-glucose isomers and d-gluconate were obtained and compared with those reported in bibliography, showing a satisfactory correlation. Comparison between experimental and calculated frequencies reveals a preference for d-gluconate anion acting as capping agent under the necessary presence of d-glucose on the surface of the AgNPs. The study of energies shows a greater affinity of d-gluconate for the silver atoms (above -1.3 eV for both geometries) than for other configurations of the glucose molecule (about -0.66 eV in the case of alpha-d-glucose).