The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide
Building on our previous studies, which have demonstrated that homochiral propagating species—(<i>R</i>*,<i>R</i>*)-[Me<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R)]<sub>2</sub>—were crucial for the heteroselectivity of [Me<...
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2025-01-01
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| author | Magdalena Kaźmierczak Łukasz Dobrzycki Maciej Dranka Paweł Horeglad |
| author_facet | Magdalena Kaźmierczak Łukasz Dobrzycki Maciej Dranka Paweł Horeglad |
| author_sort | Magdalena Kaźmierczak |
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| description | Building on our previous studies, which have demonstrated that homochiral propagating species—(<i>R</i>*,<i>R</i>*)-[Me<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R)]<sub>2</sub>—were crucial for the heteroselectivity of [Me<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me)]<sub>2</sub> in the ring-opening polymerization (ROP) of racemic lactide (<i>rac</i>-LA), we have investigated the effect of alkyl groups on the structure and catalytic properties of dialkylgallium alkoxides in the ROP of <i>rac</i>-LA. Therefore, we have isolated and characterized the <i>rac</i>-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me]<sub>2</sub> (R = Et (<b>1</b>), <i><sup>i</sup></i>Pr (<b>2</b>) and <i>rac</i>-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)C<sub>5</sub>H<sub>4</sub>N]<sub>2</sub> (R = Et (<b>3</b>), <i><sup>i</sup></i>Pr (<b>4</b>)) complexes, to demonstrate the effect of alkyl groups on the chiral recognition induced the formation of the respective homochiaral species—(<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me)]<sub>2</sub> and (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)C<sub>5</sub>H<sub>4</sub>N]<sub>2</sub>. Moreover, we have investigated the structure of (<i>S</i>,<i>S</i>)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me]<sub>2</sub> (R = Et ((<i>S</i>,<i>S</i>)-<b>1</b>, R = <i><sup>i</sup></i>Pr ((<i>S</i>,<i>S</i>)-<b>2</b>,) and their catalytic activity in the ROP of <i>rac</i>-LA. With an increase in the bulkiness of alkyl substituents on gallium the following can be observed: (a) the tendency for the formation of homochiral complexes decreased, (b) the symmetry of homochiral (<i>S</i>,<i>S</i>)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me]<sub>2</sub> (M = Me, Et (<i>S</i>,<i>S</i>)-<b>1</b>), <i><sup>i</sup></i>Pr (<i>S</i>,<i>S</i>)-<b>2</b>) changed, and both have resulted in (c) lower or no heteroselectivtity across these complexes in the ROP of <i>rac</i>-LA. Importantly, the results have confirmed the crucial role of the chiral-induced formation of homochiral asymmetric dimers on the heteroselectivity of dialkylgallium alkoxides in the ROP of <i>rac</i>-LA. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-ff18a73467214f7d834a830ebbff3ce92025-01-10T13:19:09ZengMDPI AGMolecules1420-30492025-01-0130119010.3390/molecules30010190The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-LactideMagdalena Kaźmierczak0Łukasz Dobrzycki1Maciej Dranka2Paweł Horeglad3Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, PolandFaculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, PolandFaculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, PolandFaculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, PolandBuilding on our previous studies, which have demonstrated that homochiral propagating species—(<i>R</i>*,<i>R</i>*)-[Me<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R)]<sub>2</sub>—were crucial for the heteroselectivity of [Me<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me)]<sub>2</sub> in the ring-opening polymerization (ROP) of racemic lactide (<i>rac</i>-LA), we have investigated the effect of alkyl groups on the structure and catalytic properties of dialkylgallium alkoxides in the ROP of <i>rac</i>-LA. Therefore, we have isolated and characterized the <i>rac</i>-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me]<sub>2</sub> (R = Et (<b>1</b>), <i><sup>i</sup></i>Pr (<b>2</b>) and <i>rac</i>-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)C<sub>5</sub>H<sub>4</sub>N]<sub>2</sub> (R = Et (<b>3</b>), <i><sup>i</sup></i>Pr (<b>4</b>)) complexes, to demonstrate the effect of alkyl groups on the chiral recognition induced the formation of the respective homochiaral species—(<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me)]<sub>2</sub> and (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)C<sub>5</sub>H<sub>4</sub>N]<sub>2</sub>. Moreover, we have investigated the structure of (<i>S</i>,<i>S</i>)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me]<sub>2</sub> (R = Et ((<i>S</i>,<i>S</i>)-<b>1</b>, R = <i><sup>i</sup></i>Pr ((<i>S</i>,<i>S</i>)-<b>2</b>,) and their catalytic activity in the ROP of <i>rac</i>-LA. With an increase in the bulkiness of alkyl substituents on gallium the following can be observed: (a) the tendency for the formation of homochiral complexes decreased, (b) the symmetry of homochiral (<i>S</i>,<i>S</i>)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>Me]<sub>2</sub> (M = Me, Et (<i>S</i>,<i>S</i>)-<b>1</b>), <i><sup>i</sup></i>Pr (<i>S</i>,<i>S</i>)-<b>2</b>) changed, and both have resulted in (c) lower or no heteroselectivtity across these complexes in the ROP of <i>rac</i>-LA. Importantly, the results have confirmed the crucial role of the chiral-induced formation of homochiral asymmetric dimers on the heteroselectivity of dialkylgallium alkoxides in the ROP of <i>rac</i>-LA.https://www.mdpi.com/1420-3049/30/1/190biodegradable polyesterspolylactidetacticityheterotacticdimersdiastereomers |
| spellingShingle | Magdalena Kaźmierczak Łukasz Dobrzycki Maciej Dranka Paweł Horeglad The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide Molecules biodegradable polyesters polylactide tacticity heterotactic dimers diastereomers |
| title | The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide |
| title_full | The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide |
| title_fullStr | The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide |
| title_full_unstemmed | The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide |
| title_short | The Effect of Alkyl Substituents on the Formation and Structure of Homochiral (<i>R</i>*,<i>R</i>*)-[R<sub>2</sub>Ga(<i>µ</i>-OCH(Me)CO<sub>2</sub>R′)]<sub>2</sub> Species—Towards the Factors Controlling the Stereoselectivity of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide |
| title_sort | effect of alkyl substituents on the formation and structure of homochiral i r i i r i r sub 2 sub ga i µ i och me co sub 2 sub r sub 2 sub species towards the factors controlling the stereoselectivity of dialkylgallium alkoxides in the ring opening polymerization of i rac i lactide |
| topic | biodegradable polyesters polylactide tacticity heterotactic dimers diastereomers |
| url | https://www.mdpi.com/1420-3049/30/1/190 |
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