Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis
Liquid coordination complexes (LCCs), which are formed between metal halides and donor molecules, represent promising catalysts. Six amide-AlCl<sub>3</sub> LCCs were successfully synthesized, followed by their characterization through NMR, Raman, and UV-visible spectroscopy. The acidity...
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MDPI AG
2023-11-01
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| Online Access: | https://www.mdpi.com/1420-3049/28/23/7857 |
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| author | Hao Li Qiong Wu Ying Liu Jinrong Bao |
| author_facet | Hao Li Qiong Wu Ying Liu Jinrong Bao |
| author_sort | Hao Li |
| collection | DOAJ |
| description | Liquid coordination complexes (LCCs), which are formed between metal halides and donor molecules, represent promising catalysts. Six amide-AlCl<sub>3</sub> LCCs were successfully synthesized, followed by their characterization through NMR, Raman, and UV-visible spectroscopy. The acidity of these LCCs was quantified by performing computational modelling of fluoride ion affinities (FIA) and experimental Gutmann–Beckett measurements. Spectroscopic analysis indicated bidentate coordination between amide ligands and Al, which induced asymmetric splitting of Al<sub>2</sub>Cl<sub>6</sub> into diverse ions such as [AlCl<sub>2</sub>L<sub>2</sub>]<sup>+</sup>, [AlCl<sub>4</sub>]<sup>−</sup>, [AlCl<sub>3</sub>L], and [Al<sub>2</sub>Cl<sub>6</sub>L]. The computed FIA was found to align well with the experimental acidity trends, thereby confirming the proposed structure of the LCC. In the alkylation tests, the LCC with a high acidity demonstrated an increase in the yields of C<sub>5</sub>-C<sub>7</sub> alkylates. These results provide an in-depth understanding of the tuneable structures of amide-AlCl<sub>3</sub> LCCs. The acidity of LCCs can be controlled by tuning the ratio of the organic ligand to AlCl<sub>3</sub>, which allows bidentate coordination to facilitate asymmetric splitting of Al<sub>2</sub>Cl<sub>6</sub>. The LCCs demonstrate a high degree of potential as versatile and sustainable acid catalysts in alkylation reactions. These findings may advance the foundational knowledge of LCCs for the purpose of targeted acid catalyst design. |
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| last_indexed | 2024-03-09T01:45:38Z |
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| spelling | doaj.art-0f46011012464dccbbd07adab838949c2023-12-08T15:22:33ZengMDPI AGMolecules1420-30492023-11-012823785710.3390/molecules28237857Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation CatalysisHao Li0Qiong Wu1Ying Liu2Jinrong Bao3School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, ChinaSchool of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, ChinaSchool of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, ChinaSchool of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, ChinaLiquid coordination complexes (LCCs), which are formed between metal halides and donor molecules, represent promising catalysts. Six amide-AlCl<sub>3</sub> LCCs were successfully synthesized, followed by their characterization through NMR, Raman, and UV-visible spectroscopy. The acidity of these LCCs was quantified by performing computational modelling of fluoride ion affinities (FIA) and experimental Gutmann–Beckett measurements. Spectroscopic analysis indicated bidentate coordination between amide ligands and Al, which induced asymmetric splitting of Al<sub>2</sub>Cl<sub>6</sub> into diverse ions such as [AlCl<sub>2</sub>L<sub>2</sub>]<sup>+</sup>, [AlCl<sub>4</sub>]<sup>−</sup>, [AlCl<sub>3</sub>L], and [Al<sub>2</sub>Cl<sub>6</sub>L]. The computed FIA was found to align well with the experimental acidity trends, thereby confirming the proposed structure of the LCC. In the alkylation tests, the LCC with a high acidity demonstrated an increase in the yields of C<sub>5</sub>-C<sub>7</sub> alkylates. These results provide an in-depth understanding of the tuneable structures of amide-AlCl<sub>3</sub> LCCs. The acidity of LCCs can be controlled by tuning the ratio of the organic ligand to AlCl<sub>3</sub>, which allows bidentate coordination to facilitate asymmetric splitting of Al<sub>2</sub>Cl<sub>6</sub>. The LCCs demonstrate a high degree of potential as versatile and sustainable acid catalysts in alkylation reactions. These findings may advance the foundational knowledge of LCCs for the purpose of targeted acid catalyst design.https://www.mdpi.com/1420-3049/28/23/7857liquid coordination complexesLewis aciditydensity functional theoryNMRC<sub>4</sub> alkylation catalysts |
| spellingShingle | Hao Li Qiong Wu Ying Liu Jinrong Bao Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis Molecules liquid coordination complexes Lewis acidity density functional theory NMR C<sub>4</sub> alkylation catalysts |
| title | Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis |
| title_full | Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis |
| title_fullStr | Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis |
| title_full_unstemmed | Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis |
| title_short | Acidity Quantification and Structure Analysis of Amide-AlCl<sub>3</sub> Liquid Coordination Complexes for C<sub>4</sub> Alkylation Catalysis |
| title_sort | acidity quantification and structure analysis of amide alcl sub 3 sub liquid coordination complexes for c sub 4 sub alkylation catalysis |
| topic | liquid coordination complexes Lewis acidity density functional theory NMR C<sub>4</sub> alkylation catalysts |
| url | https://www.mdpi.com/1420-3049/28/23/7857 |
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