Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol
Dicopper-substituted polyoxovanadate [Cu<sub>2</sub>V<sub>16</sub>O<sub>44</sub>(NO<sub>3</sub>)]<sup>5−</sup> (Cu2V16) was synthesized through the reaction of [Cu<sub>2</sub>V<sub>8</sub>O<sub>24</sub>]&...
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MDPI AG
2024-02-01
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| Series: | Inorganics |
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| Online Access: | https://www.mdpi.com/2304-6740/12/2/61 |
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| author | Isshin Yoshida Ryoji Mitsuhashi Yuji Kikukawa Yoshihito Hayashi |
| author_facet | Isshin Yoshida Ryoji Mitsuhashi Yuji Kikukawa Yoshihito Hayashi |
| author_sort | Isshin Yoshida |
| collection | DOAJ |
| description | Dicopper-substituted polyoxovanadate [Cu<sub>2</sub>V<sub>16</sub>O<sub>44</sub>(NO<sub>3</sub>)]<sup>5−</sup> (Cu2V16) was synthesized through the reaction of [Cu<sub>2</sub>V<sub>8</sub>O<sub>24</sub>]<sup>4−</sup> and [V<sub>4</sub>O<sub>12</sub>]<sup>4−</sup> in the presence of nitrate salt. From single crystal X-ray analysis, Cu2V16 exhibited the same helical structure as that of nitrate-incorporated polyoxovanadate, [V<sub>18</sub>O<sub>46</sub>(NO<sub>3</sub>)]<sup>5−</sup> (V18). Both complexes had the same framework with the same guest anion and are considered to be substituted isomers for each other by replacing two Cu<sup>2+</sup> ions and two [VO]<sup>2+</sup> ions. The incorporated nitrate showed short and long N–O bond lengths (1.14, 1.26 and 1.30 Å) as in the case of V18 (1.09, 1.16 and 1.28 Å). Reflecting the inequivalent bond lengths of the nitrate, the IR spectrum of V18 shows split peaks at 1359 and 1342 cm<sup>−1</sup>. But the Cu2V16 spectrum showed a single peak due to the presence of nitrate at 1353 cm<sup>−1</sup>. When the temperature was lowered, the nitrate peak in Cu2V16 was split into two positions at 1354 and 1345 cm<sup>−1</sup> when the temperature reached −140 °C. These results indicate that the nitrate incorporated in Cu2V16 rotates relatively easily in the Cu2V16 cavity at room temperature compared to V18. In addition, the oxidation of 1-phenyl ethanol to acetophenone with Cu2V16 smoothly proceeded in comparison with V18. By taking advantage of the same framework in both catalysts, we can deduce the position of potential active sites in the oxidation reaction. We have concluded that the most active site is not on the peripheral of the vanadate framework, but it is reasonable to suggest that the active site is on the substituted copper atoms rather than the polyoxovanadate framework. |
| first_indexed | 2024-03-07T22:28:05Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-07T22:28:05Z |
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| spelling | doaj.art-de23c3bfaa254891bf90d6cbdfd40fd72024-02-23T15:21:23ZengMDPI AGInorganics2304-67402024-02-011226110.3390/inorganics12020061Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl EthanolIsshin Yoshida0Ryoji Mitsuhashi1Yuji Kikukawa2Yoshihito Hayashi3Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, JapanInstitute of Liberal Arts and Science, Kanazawa University, Kakuma, Kanazawa 920-1192, JapanDepartment of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, JapanDepartment of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, JapanDicopper-substituted polyoxovanadate [Cu<sub>2</sub>V<sub>16</sub>O<sub>44</sub>(NO<sub>3</sub>)]<sup>5−</sup> (Cu2V16) was synthesized through the reaction of [Cu<sub>2</sub>V<sub>8</sub>O<sub>24</sub>]<sup>4−</sup> and [V<sub>4</sub>O<sub>12</sub>]<sup>4−</sup> in the presence of nitrate salt. From single crystal X-ray analysis, Cu2V16 exhibited the same helical structure as that of nitrate-incorporated polyoxovanadate, [V<sub>18</sub>O<sub>46</sub>(NO<sub>3</sub>)]<sup>5−</sup> (V18). Both complexes had the same framework with the same guest anion and are considered to be substituted isomers for each other by replacing two Cu<sup>2+</sup> ions and two [VO]<sup>2+</sup> ions. The incorporated nitrate showed short and long N–O bond lengths (1.14, 1.26 and 1.30 Å) as in the case of V18 (1.09, 1.16 and 1.28 Å). Reflecting the inequivalent bond lengths of the nitrate, the IR spectrum of V18 shows split peaks at 1359 and 1342 cm<sup>−1</sup>. But the Cu2V16 spectrum showed a single peak due to the presence of nitrate at 1353 cm<sup>−1</sup>. When the temperature was lowered, the nitrate peak in Cu2V16 was split into two positions at 1354 and 1345 cm<sup>−1</sup> when the temperature reached −140 °C. These results indicate that the nitrate incorporated in Cu2V16 rotates relatively easily in the Cu2V16 cavity at room temperature compared to V18. In addition, the oxidation of 1-phenyl ethanol to acetophenone with Cu2V16 smoothly proceeded in comparison with V18. By taking advantage of the same framework in both catalysts, we can deduce the position of potential active sites in the oxidation reaction. We have concluded that the most active site is not on the peripheral of the vanadate framework, but it is reasonable to suggest that the active site is on the substituted copper atoms rather than the polyoxovanadate framework.https://www.mdpi.com/2304-6740/12/2/61polyoxovanadatesmetal-substitutionnitratealcohol oxidationsupra-ceramics |
| spellingShingle | Isshin Yoshida Ryoji Mitsuhashi Yuji Kikukawa Yoshihito Hayashi Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol Inorganics polyoxovanadates metal-substitution nitrate alcohol oxidation supra-ceramics |
| title | Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol |
| title_full | Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol |
| title_fullStr | Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol |
| title_full_unstemmed | Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol |
| title_short | Synthesis of Copper-Substituted Polyoxovanadate and Oxidation of 1-Phenyl Ethanol |
| title_sort | synthesis of copper substituted polyoxovanadate and oxidation of 1 phenyl ethanol |
| topic | polyoxovanadates metal-substitution nitrate alcohol oxidation supra-ceramics |
| url | https://www.mdpi.com/2304-6740/12/2/61 |
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