Vibrational (Raman and SERS) and electronic UV study on triazine herbicides.

The triazine group is a well known class of herbicides and has been widely used for more than 40 years; these chemicals inhibit photosynthesis in plants by blocking the electron transfer at the reducing site of chloroplast photosystem II. Atrazine, and the later introduced simetryn and prometryn are the most used triazine herbicides. In this paper we studied the SERS spectra on a Ag colloidal suspension, resulting from the controlied citrate reduction of silver nitrate, of all considered herbicides together with the Raman and UV spectra of the considered herbicides both pure as well in solution. To a better explanation of the binding mechanism of herbicides to a metal (Ag) surface we made a theoretical extensive ab initio calculations, performed at the HF/6-31G** level on triazines alone as well on the same compounds in solution and adsorbed on a Ag metal cluster.