INFRARED AND RAMAN-SPECTRA OF PHTALATE, ISOPHTHALATE AND TEREPHTHALATE IONS

Infrared spectra of anhydrous dipotassic salts of phtalic, isophtalic and terephtalic acids in KBr pellets as well as their Raman spectra as microcrystalline powder and saturated aqueous solutions, have been investigated. On this basis, a tentative assignment of the observed vibrational bands is proposed for each ion, the relevant molecular point groups being C2, C2ν and D2h respectively. Characteristic COO- vibrations show frequencies which do not change noticeably from one to other ion, with the exception of γ(OCO) which appears in the spectrum of terephtalate ion some 150 cm-1 higher than in the other two cases. © 1979.