0

Solvent Dependence of Conformational Stability and Analysis of Vibrational Spectra of 2,2,3,3,3-pentafluoro-1-propanol

Hassan M Badawi, Wolfgang Förner

Spectrochim Acta A Mol Biomol Spectrosc. 2008 Nov 15;71(2):388-97.

PMID: 18280783

Abstract:

The conformational stability of 2,2,3,3,3-pentafluoro-1-propanol was investigated by the DFT-B3LYP/6-311+G** and the ab initio MP2/6-311+G** calculations. The calculated potential energy curves of 2,2,3,3,3-pentafluoro-1-propanol at both levels of theory were consistent with three distinct minima that correspond to Trans-gauche-gauche (Tgg), trans-trans-gauche (Ttg) and trans-gauche-gauche(-) (Tgg1) conformers in the order of decreasing relative stability. The equilibrium constants for the conformational interconversion of 2,2,3,3,3-pentafluoro-1-propanol were calculated and found to correspond to an equilibrium mixture of about 46% Tgg, 43% Ttg and 11% Tgg1 conformations at 298.15K. The calculated (%Ttg/%Tgg) ratio of 0.93 is consistent with the 0.85 ratio of the observed intensities of the 772 and 794 cm(-1) lines in the Raman spectrum of the liquid. The nature of the high energy Ttg conformation was verified by solvent experiments using formamide (epsilon = 109.5) and acetonitrile (epsilon = 37). The vibrational frequencies of the molecule in its stable forms were computed at B3LYP level and complete vibrational assignments were made based on normal coordinate calculations and comparison with experimental data of the molecule.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP422059 2,2,3,3,3-Pentafluoro-1-propanol 2,2,3,3,3-Pentafluoro-1-propanol 422-05-9 Price
qrcode