Síntese e caracterização óptica de derivados de acetofenona iodados

Abstract

Iodo-functionalized aromatic compounds have been the subject of numerous studies to be present in a variety of biologically active substances, natural products, agricultural chemicals and compounds used in developing new materials. In the present study, aromatic compounds functionalized with iodine by using I2 and H2O2 30% (m/v) in water at room temperature were prepared. A mixture containing 4-hydroxyacetophenone (4-HA), 1.5 equivalent of I2 and 3 equivalent of H2O2 30% (m/v) in water was submitted to an iodation reaction, producing 4-hydroxy-3-iodoacetophenone (4-HAM) and 4-hydro-3,5 diiodoacetophenone (4-HAD). From 4-HAD, 5-acetyl-1,3-diiodo-2- phenoxybenzene (5AcD) was produced by an O-arylation reaction promoted by 2-(trimethylsilyl) phenyl triflates under mild reaction conditions in the presence of CsF in acetonitrile at room temperature. Then, UV-Vis absorption, molecular fluorescence, FT-IR and Raman spectroscopy were performed in order to determine the optical properties these molecules. These characterizations were motivated by the fact that, to the best of our knowledge, there is no paper reporting the optical properties of these iodinated acetophenones. In summary, our results shown that the presence of the iodine, as a substituent in the aromatic ring, induced a significant modification in the optical proprieties of the studied compounds. Alterations in the absorption, fluorescence, infrared and Raman spectra were observed with the addition of the iodine in the molecular structure. Nevertheless, a huge change in the optical response was detected for the 4-HAD molecules, where an increase in fluorescence quantum yield was determined.