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Wu B, Seifert NA, Oswald S, Jäger W, Xu Y. Rotational Spectroscopy of the 2,2,3,3,3-Pentafluoropropanol⋅⋅⋅Water Complex: Conformations and Large Amplitude Motions. Chemphyschem 2022; 23:e202200348. [PMID: 35759723 DOI: 10.1002/cphc.202200348] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/24/2022] [Indexed: 11/08/2022]
Abstract
The 2,2,3,3,3-pentafluoropropanol (PFP) monomer can exist in five conformations defined by the CCCO and CCOH dihedral angles: four mirror-imaged pairs (G+g+/G-g-, G+g-/G-g+, G+t/G-t, Tg+/Tg-) and an achiral Tt form. We examined the conformational landscape of the PFP⋅⋅⋅water complex using chirped pulsed Fourier transform microwave spectroscopy and theoretical calculations. Rotational spectra of two PFP⋅⋅⋅water conformers, PFPG+g+⋅⋅⋅WH and PFPTg+⋅⋅⋅WH , and seven deuterated isotopologues of each, were assigned. Tunneling splittings were observed for both conformers and are attributed to the exchange of the bonded and non-bonded hydrogen atoms of water. On the other hand, the tunneling splitting associated with the OH flipping motion in PFPTg+/Tg- appears to be quenched upon hydrogen bonding with water. The large amplitude motions associated with the water subunits were examined in detail to explain the very different magnitudes of the experimental and theoretical permanent electric dipole moment components. The study highlights the challenge in correctly identifying the conformers observed when large amplitude motions are involved. Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analyses, as well as electrostatic potential (ESP) calculations were carried out to explore the nature of the non-covalent interactions and to appreciate the effects of fluorination.
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Affiliation(s)
- Bowei Wu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Nathan A Seifert
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.,Chemistry and Chemical & Biomedical Engineering Department University of New Haven, 300 Boston Post Rd, West Haven, CT, 06516, USA
| | - Sönke Oswald
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.,Institut für Physikalische Chemie, Georg-August-Universität Göttingen, Tammannstraße 6, 37077, Göttingen, Germany
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
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Wu B, Seifert NA, Insausti A, Ma J, Oswald S, Jaeger W, Xu Y. 2,2,3,3,3-pentafluoro-1-propanol and its dimer: structural diversity, conformational conversion, and tunnelling motion. Phys Chem Chem Phys 2022; 24:14975-14984. [DOI: 10.1039/d2cp01895k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rotational spectra of the 2,2,3,3,3-pentafluoro-1-propanol (PFP) were measured using cavity and chirped pulse Fourier transform microwave spectrometers. Of the nine possible PFP configurations which include four mirror-imaged pairs and an...
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Udayakumar V, Periandy S, Karabacak M, Ramalingam S. Experimental (FT-IR, FT-Raman) and theoretical (HF and DFT) investigation and HOMO and LUMO analysis on the structure of p-fluoronitrobenzene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 83:575-586. [PMID: 21955946 DOI: 10.1016/j.saa.2011.09.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/19/2011] [Accepted: 09/01/2011] [Indexed: 05/31/2023]
Abstract
FT-IR and FT-Raman spectra of p-fluoronitrobenzene (FNO(2)C(6)H(4)) have been recorded in the region 4000-100 cm(-1). In this work, the experimental and theoretical spectra of p-fluoronitrobenzene (p-FNBz) are studied. The molecular geometry and vibrational frequencies are calculated in the ground state of molecule using ab initio Hartree-Fock (HF) and DFT (B3LYP and LSDA) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets. The computed values of frequencies are scaled to yield good coherence with observed values by using suitable factor. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The observed and calculated frequencies are found to be in very good agreement. The alteration of vibration bands due to the substitutions at the first and fourth position of the skeletal ring is also investigated from their characteristic region of linked spectrum. A study on the electronic properties, such as absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by time dependent DFT (TD-DFT) approach. The electronic structure and the assignment of the absorption bands in the electronic spectra of steady compounds are discussed. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The thermodynamic properties of the title compound at different temperatures have been calculated in gas phase, revealing the correlations between standard heat capacities (C) standard entropies (S), standard enthalpy changes (H) and temperatures.
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Affiliation(s)
- V Udayakumar
- Department of Physics, Thiru A. Govindaswamy Arts College, Tindivanam, Tamilnadu, India
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