Silver nanoparticles
(AgNPs) were synthetized and employed in surface-enhanced
Raman scattering measurements to study the chemical behavior when
thiacloprid (Thia) interacts with the surface of Ag nanospheres (AgNSp)
and Ag nanostars (AgNSt) upon excitation of the system with a 785
nm laser. Experimental results show that the deactivation of the localized
surface plasmon resonance induces structural changes in Thia. When
AgNSp are used, it is possible to observe a mesomeric effect in the
cyanamide moiety. On the other hand, when AgNSt are employed, it promotes
the cleavage of the methylene (−CH2−) bridge
in Thia to produce two molecular fragments. To support these results,
theoretical calculations based on topological parameters described
by the atoms in molecules theory, Laplacian of the electron density
at the bond critical point (∇2ρ BCP), Laplacian
bond order, and bond dissociation energies were made, confirming that
the bond cleavage is centered at the −CH2–
bridge in Thia.