Factor analysis as a complement to band resolution techniques. VI. Complex formation between pentachlorophenol-OD and acetone

Complex formation between pentachlorophenol-OD (PCP-OD) and acetone and acetone-d6 in CCl4 solution has been studied. Digitized infrared spectra in the O—D stretching region ν(OD) of PCP-OD and the C—O stretching region ν(CO) of acetone have been recorded from solutions of various concentrations. The present results are compared with previous work on complex formation between PCP and the same acceptor molecules. In the ν(OD) region, factor analysis (principal component analysis) and a concentration study of the areas of the resolved band components suggest that two (1:1) complexes occur in solution. The equilibrium constant obtained for one of the complexes shows an isotope effect due to deuteration of the proton donor. In the ν(CO) region, only one band due to complexed species was resolved. Equilibrium constants calculated using the results from the ν(OD) and ν(CO) regions are in good agreement with each other.