title: Infrared and Raman spectroscopic characterization of some organic substituted hybrid silicas.
abstract: Nine hybrid silicas bearing the organic substituent groups methyl, octyl, octadecyl, vinyl, phenyl, mercaptopropyl, isocyanatopropyl, chloropropyl and glycidoxypropyl were synthesized by an acid-catalyzed, hydrolytic sol-gel process. The resulting solid materials were characterized by their absorbance and attenuated total reflection (ATR) IR and Raman spectra. The latter technique proved to be particularly useful in the identification of the organic moieties in the hybrid silicas. The effect of the presence of the organic groups on the silica networks was also investigated - there were increases observed in both the SiOSi bond angles and bond lengths. Moreover, deconvolution of the IR-active antisymmetric SiOSi stretching bands permitted detection of the four- and six-membered siloxane rings present in the silicas. There proved to be a greater number of four-membered rings on the surfaces of the particles. Both IR and Raman spectroscopy proved to be invaluable in the characterization of these hybrid materials.
authors.affiliation: Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500 Porto Alegre, Brazil.
authors.forename: Larissa B
authors.initials: LB
authors.lastname: Capeletti
authors.affiliation: Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500 Porto Alegre, Brazil.
authors.forename: Ione M
authors.initials: IM
authors.lastname: Baibich
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal H3A 2K6, Canada.
authors.forename: Ian S
authors.initials: IS
authors.lastname: Butler
authors.affiliation: Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500 Porto Alegre, Brazil. Electronic address: jhzds@iq.ufrgs.br.
authors.forename: João H Z
authors.initials: JH
authors.lastname: dos Santos
mesh_terms: D008958:Models, Molecular; D017646:Organosilicon Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D044367:Phase Transition; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D017646:Organosilicon Compounds; D012822:Silicon Dioxide
keywords: Hybrid silica; Infrared and Raman spectroscopy; Organosilanes; Sol–gel process