Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect
The century-old, well-known odd–even effect phenomenon is still a very attractive and intriguing topic in supramolecular and nano-scale organic chemistry. As a part of our continuous efforts in the study of supramolecular chemistry, we have prepared three novel aromatic alcohols (1,2-bis[2-(hydroxym...
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MDPI AG
2022-06-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/12/3781 |
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| author | Tomislav Balić Marija Paurević Marta Počkaj Martina Medvidović-Kosanović Dominik Goman Aleksandar Széchenyi Zsolt Preisz Sándor Kunsági-Máté |
| author_facet | Tomislav Balić Marija Paurević Marta Počkaj Martina Medvidović-Kosanović Dominik Goman Aleksandar Széchenyi Zsolt Preisz Sándor Kunsági-Máté |
| author_sort | Tomislav Balić |
| collection | DOAJ |
| description | The century-old, well-known odd–even effect phenomenon is still a very attractive and intriguing topic in supramolecular and nano-scale organic chemistry. As a part of our continuous efforts in the study of supramolecular chemistry, we have prepared three novel aromatic alcohols (1,2-bis[2-(hydroxymethyl)phenoxy]butylene (<b>Do4OH</b>), 1,2-bis[2-(hydroxymethyl)phenoxy]pentylene (<b>Do5OH</b>) and 1,2-bis[2-(hydroxymethyl)phenoxy]hexylene (<b>Do6OH</b>)) and determined their crystal and molecular structures by single-crystal X-ray diffraction. In all compounds, two benzyl alcohol groups are linked by an aliphatic chain of different lengths (CH<sub>2</sub>)<sub>n</sub>; <i>n</i> = <b>4</b>, <b>5</b> and <b>6</b>. The major differences in the molecular structures were found in the overall planarity of the molecules and the conformation of the aliphatic chain. Molecules with an even number of CH<sub>2</sub> groups tend to be planar with an all-<i>trans</i> conformation of the aliphatic chain, while the odd-numbered molecule is non-planar, with partial <i>gauche</i> conformation. A direct consequence of these structural differences is visible in the melting points—odd-numbered compounds of a particular series display systematically lower melting points. Crystal and molecular structures were additionally studied by the theoretical calculations and the melting points were correlated with packing density and the number of CH<sub>2</sub> groups. The results have shown that the generally accepted rule, higher density = higher stability = higher melting point, could not be applied to these compounds. It was found that the denser packaging causes an increase in the percentage of repulsive H‧‧‧H interactions, thereby reducing the stability of the crystal, and consequently, the melting points. Another interesting consequence of different molecular structures is their electrochemical and antioxidative properties—a non-planar structure displays the highest oxidation peak of hydroxyl groups and moderate antioxidant activity. |
| first_indexed | 2024-03-09T22:56:40Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-09T22:56:40Z |
| publishDate | 2022-06-01 |
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| series | Molecules |
| spelling | doaj.art-f08abfd005694c0ebf0a8eae5a8163f32023-11-23T18:11:12ZengMDPI AGMolecules1420-30492022-06-012712378110.3390/molecules27123781Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even EffectTomislav Balić0Marija Paurević1Marta Počkaj2Martina Medvidović-Kosanović3Dominik Goman4Aleksandar Széchenyi5Zsolt Preisz6Sándor Kunsági-Máté7Department of Chemistry, Josip Juraj Strossmayer University of Osijek, Cara Hadrijana 8/A, 31000 Osijek, CroatiaDepartment of Chemistry, Josip Juraj Strossmayer University of Osijek, Cara Hadrijana 8/A, 31000 Osijek, CroatiaFaculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, SloveniaDepartment of Chemistry, Josip Juraj Strossmayer University of Osijek, Cara Hadrijana 8/A, 31000 Osijek, CroatiaDepartment of Chemistry, Josip Juraj Strossmayer University of Osijek, Cara Hadrijana 8/A, 31000 Osijek, CroatiaDepartment of Chemistry, Josip Juraj Strossmayer University of Osijek, Cara Hadrijana 8/A, 31000 Osijek, CroatiaFaculty of Pharmacy, Institute of Organic and Medicinal Chemistry, University of Pécs, Szigeti 12, 7624 Pécs, HungaryFaculty of Pharmacy, Institute of Organic and Medicinal Chemistry, University of Pécs, Szigeti 12, 7624 Pécs, HungaryThe century-old, well-known odd–even effect phenomenon is still a very attractive and intriguing topic in supramolecular and nano-scale organic chemistry. As a part of our continuous efforts in the study of supramolecular chemistry, we have prepared three novel aromatic alcohols (1,2-bis[2-(hydroxymethyl)phenoxy]butylene (<b>Do4OH</b>), 1,2-bis[2-(hydroxymethyl)phenoxy]pentylene (<b>Do5OH</b>) and 1,2-bis[2-(hydroxymethyl)phenoxy]hexylene (<b>Do6OH</b>)) and determined their crystal and molecular structures by single-crystal X-ray diffraction. In all compounds, two benzyl alcohol groups are linked by an aliphatic chain of different lengths (CH<sub>2</sub>)<sub>n</sub>; <i>n</i> = <b>4</b>, <b>5</b> and <b>6</b>. The major differences in the molecular structures were found in the overall planarity of the molecules and the conformation of the aliphatic chain. Molecules with an even number of CH<sub>2</sub> groups tend to be planar with an all-<i>trans</i> conformation of the aliphatic chain, while the odd-numbered molecule is non-planar, with partial <i>gauche</i> conformation. A direct consequence of these structural differences is visible in the melting points—odd-numbered compounds of a particular series display systematically lower melting points. Crystal and molecular structures were additionally studied by the theoretical calculations and the melting points were correlated with packing density and the number of CH<sub>2</sub> groups. The results have shown that the generally accepted rule, higher density = higher stability = higher melting point, could not be applied to these compounds. It was found that the denser packaging causes an increase in the percentage of repulsive H‧‧‧H interactions, thereby reducing the stability of the crystal, and consequently, the melting points. Another interesting consequence of different molecular structures is their electrochemical and antioxidative properties—a non-planar structure displays the highest oxidation peak of hydroxyl groups and moderate antioxidant activity.https://www.mdpi.com/1420-3049/27/12/3781aromatic alcoholsaliphatic chainodd–even effectmelting point deviationcrystal structures |
| spellingShingle | Tomislav Balić Marija Paurević Marta Počkaj Martina Medvidović-Kosanović Dominik Goman Aleksandar Széchenyi Zsolt Preisz Sándor Kunsági-Máté Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect Molecules aromatic alcohols aliphatic chain odd–even effect melting point deviation crystal structures |
| title | Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect |
| title_full | Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect |
| title_fullStr | Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect |
| title_full_unstemmed | Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect |
| title_short | Influence of Aliphatic Chain Length on Structural, Thermal and Electrochemical Properties of <i>n</i>-alkylene Benzyl Alcohols: A Study of the Odd–Even Effect |
| title_sort | influence of aliphatic chain length on structural thermal and electrochemical properties of i n i alkylene benzyl alcohols a study of the odd even effect |
| topic | aromatic alcohols aliphatic chain odd–even effect melting point deviation crystal structures |
| url | https://www.mdpi.com/1420-3049/27/12/3781 |
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