FTIR/PCA study of propanol in argon matrix: The initial stage of clustering and conformational transitions

Abstract

FTIR spectra of 1-propanol in an argon matrix were studied in the range 11 to 30 K. Principal component analysis of dynamic FTIR spectra and nonlinear band shape fitting has been carried out. The peaks of monomer, open dimer, mixed propanol-water dimer and those of higher H-bond clusters have been resolved and analyzed. The attribution of certain FTIR peaks has been supported by proper density functional theory calculations. Analyzing dependences of the integral band intensities of various aggregates on temperature it has been deduced that in the initial stage of clustering monomers and dimers are the basic building blocks forming higher H-bond clusters. The peaks assigned to two conformers of monomers and mixed propanol-water dimers were investigated processing the temperature dependences of their integral intensities in Arrhenius plot. The obtained values of 0.18 kJ⋅mol -1 for propanol monomer and 0.26 kJ⋅mol -1 for mixed dimer are well comparable with the energy differences between the global minimum conformation of 1-propanol (Gt) and some other energetically higher structures (Tt or Tg). PACS

Solid-state 1H and 31P NMR and FTIR spectroscopy study of static and dynamic structures in sol-gel derived calcium hydroxyapatites

“…6). This observation reminds us of the behaviour of νO-H bandwidths in the FTIR spectra of propanol H-bond aggregates isolated in the cavities of argon matrix [23] and shows that the molecules of ad- Fig. 6.…”

Molecular Isomerization in n-Propanol Dimers

“…As mentioned in different works [2][3][4][5][6][11][12][13][14], the clusterization of molecules in condensed alcohols leads to red shifts of the spectral bands corresponding to the frequencies of stretching O-H vibrations. The authors of those works tried to compare the vibrational spectra obtained by quantum chemistry calculations with experimental ones using only one structure of each size.…”

“…Alcohols belong to the class of partially ordered liquids. Due to the presence of a hydroxyl group in their molecules, alcohols can form various cluster structures in condensed phases [1][2][3] and inert matrix isolation [3][4][5][6], in helium nanodroplets [7,8], in solutions [9], and even in the gas phase [10]. Clusterization processes are intensively studied with different experimental and theoretical techniques [3][4][5][6][7][8][9][10][11][12][13][14].…”

“…Due to the presence of a hydroxyl group in their molecules, alcohols can form various cluster structures in condensed phases [1][2][3] and inert matrix isolation [3][4][5][6], in helium nanodroplets [7,8], in solutions [9], and even in the gas phase [10]. Clusterization processes are intensively studied with different experimental and theoretical techniques [3][4][5][6][7][8][9][10][11][12][13][14]. In addition to the formation of molecular structures with various sizes, the important role in investigations of a cluster structure of alcohols is played by the molecular isomerization [15][16][17][18][19][20][21][22][23][24].…”

“…Propanol is widely studied, as it is one of the most useable alcohol for various applications. Its conformational properties were studied in supersonic jets [17,21], cryogenic matrices [6,17], gas and liquid phases [16], and CCl 4 solutions at low concentrations [25]. This research is aimed to determine, if molecular isomerization could lead to a non-uniform distribution of n-propanol dimers consisting of different molecular isomers.…”