Abstract

Silver nanoparticles(AgNPs) were synthetized and employed in surface-enhancedRaman scattering measurements to study the chemical behavior whenthiacloprid (Thia) interacts with the surface of Ag nanospheres (AgNSp)and Ag nanostars (AgNSt) upon excitation of the system with a 785nm laser. Experimental results show that the deactivation of the localizedsurface plasmon resonance induces structural changes in Thia. WhenAgNSp are used, it is possible to observe a mesomeric effect in thecyanamide moiety. On the other hand, when AgNSt are employed, it promotesthe cleavage of the methylene (-CH2-) bridgein Thia to produce two molecular fragments. To support these results,theoretical calculations based on topological parameters describedby the atoms in molecules theory, Laplacian of the electron densityat the bond critical point ( backward difference (2)rho BCP), Laplacianbond order, and bond dissociation energies were made, confirming thatthe bond cleavage is centered at the -CH2-bridge in Thia.