Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy
The rotational spectrum of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>2</mn><mo>′</mo></msup></semantics></math></inline-formula>-hydroxyacetophenon...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
|
| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/29/24/5842 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846103523402448896 |
|---|---|
| author | Salvatore Boi Sonia Melandri Luca Evangelisti Assimo Maris |
| author_facet | Salvatore Boi Sonia Melandri Luca Evangelisti Assimo Maris |
| author_sort | Salvatore Boi |
| collection | DOAJ |
| description | The rotational spectrum of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>2</mn><mo>′</mo></msup></semantics></math></inline-formula>-hydroxyacetophenone has been recorded and assigned for the first time using a Stark-modulated free-jet absorption millimeter-wave (FJ-AMMW) spectrometer in the 59.6–74.5 GHz frequency range. The most stable conformer has been detected and assigned: <i>A</i> = 2277.076(11), <i>B</i> = 1212.113(5) and <i>C</i> = 795.278(5) MHz. It is characterized by a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>s</mi></msub></semantics></math></inline-formula> symmetry where a strong hydrogen bond between the acetyl oxygen atom and the hydroxyl atom takes place. The transition lines show a fine structure due to the internal rotation of the methyl group, which allowed the determination of a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>V</mi><mn>3</mn></msub></semantics></math></inline-formula> = 565.1(5) <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>cm</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> barrier. The corresponding tunneling splittings have been estimated to be 51 MHz. Calculations at the B3LYP-D3(BJ)/Def2-TZVP level underestimate the height of the barrier by about 156 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>cm</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>. This value decreases to 25 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>cm</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> with MP2/aug-cc-pVTZ. |
| format | Article |
| id | doaj-art-a90a0205974b4161bae6373486c51aaf |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj-art-a90a0205974b4161bae6373486c51aaf2024-12-27T14:42:25ZengMDPI AGMolecules1420-30492024-12-012924584210.3390/molecules29245842Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave SpectroscopySalvatore Boi0Sonia Melandri1Luca Evangelisti2Assimo Maris3Department of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, ItalyDepartment of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, ItalyInterdepartmental Centre for Industrial Aerospace Research (CIRI Aerospace), University of Bologna, 47521 Cesena, ItalyDepartment of Chemistry G. Ciamician, University of Bologna, 40126 Bologna, ItalyThe rotational spectrum of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>2</mn><mo>′</mo></msup></semantics></math></inline-formula>-hydroxyacetophenone has been recorded and assigned for the first time using a Stark-modulated free-jet absorption millimeter-wave (FJ-AMMW) spectrometer in the 59.6–74.5 GHz frequency range. The most stable conformer has been detected and assigned: <i>A</i> = 2277.076(11), <i>B</i> = 1212.113(5) and <i>C</i> = 795.278(5) MHz. It is characterized by a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>s</mi></msub></semantics></math></inline-formula> symmetry where a strong hydrogen bond between the acetyl oxygen atom and the hydroxyl atom takes place. The transition lines show a fine structure due to the internal rotation of the methyl group, which allowed the determination of a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>V</mi><mn>3</mn></msub></semantics></math></inline-formula> = 565.1(5) <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>cm</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> barrier. The corresponding tunneling splittings have been estimated to be 51 MHz. Calculations at the B3LYP-D3(BJ)/Def2-TZVP level underestimate the height of the barrier by about 156 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>cm</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>. This value decreases to 25 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>cm</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> with MP2/aug-cc-pVTZ.https://www.mdpi.com/1420-3049/29/24/5842rotational spectroscopymethyl internal rotationmolecular structurearomatic moleculessupersonic expansion |
| spellingShingle | Salvatore Boi Sonia Melandri Luca Evangelisti Assimo Maris Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy Molecules rotational spectroscopy methyl internal rotation molecular structure aromatic molecules supersonic expansion |
| title | Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy |
| title_full | Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy |
| title_fullStr | Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy |
| title_full_unstemmed | Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy |
| title_short | Molecular Structure and Internal Dynamics of 2<sup>′</sup>-Hydroxyacetophenone by Free-Jet Absorption Millimeter-Wave Spectroscopy |
| title_sort | molecular structure and internal dynamics of 2 sup sup hydroxyacetophenone by free jet absorption millimeter wave spectroscopy |
| topic | rotational spectroscopy methyl internal rotation molecular structure aromatic molecules supersonic expansion |
| url | https://www.mdpi.com/1420-3049/29/24/5842 |
| work_keys_str_mv | AT salvatoreboi molecularstructureandinternaldynamicsof2supsuphydroxyacetophenonebyfreejetabsorptionmillimeterwavespectroscopy AT soniamelandri molecularstructureandinternaldynamicsof2supsuphydroxyacetophenonebyfreejetabsorptionmillimeterwavespectroscopy AT lucaevangelisti molecularstructureandinternaldynamicsof2supsuphydroxyacetophenonebyfreejetabsorptionmillimeterwavespectroscopy AT assimomaris molecularstructureandinternaldynamicsof2supsuphydroxyacetophenonebyfreejetabsorptionmillimeterwavespectroscopy |