Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production

In this article, we investigate the encapsulation of K<sub>2</sub>[Ni(maleonitriledithiolate)<sub>2</sub>] (<b>1</b>) within a host molecule, β-cyclodextrin (β-CD), via single-crystal X-ray analysis. An inclusion complex, K<sub>2</sub>{[Ni(maleonitrile...

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Main Authors: Tomohiko Hamaguchi, Yuudai Iseki, Ryuta Ishikawa, Akio Mishima, Satoshi Kawata
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/29/24/5858
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author Tomohiko Hamaguchi
Yuudai Iseki
Ryuta Ishikawa
Akio Mishima
Satoshi Kawata
author_facet Tomohiko Hamaguchi
Yuudai Iseki
Ryuta Ishikawa
Akio Mishima
Satoshi Kawata
author_sort Tomohiko Hamaguchi
collection DOAJ
description In this article, we investigate the encapsulation of K<sub>2</sub>[Ni(maleonitriledithiolate)<sub>2</sub>] (<b>1</b>) within a host molecule, β-cyclodextrin (β-CD), via single-crystal X-ray analysis. An inclusion complex, K<sub>2</sub>{[Ni(maleonitriledithiolate)<sub>2</sub>]@(β-CD)<sub>2</sub>} (<b>2</b>), was constructed from <b>1</b> and two β-CDs. The anion guest Ni complex included a host cavity, constructed using two β-CDs, and the Ni atom of the anion was located between the two hydrophilic primary rims. Ultraviolet-visible absorption spectroscopy revealed that inclusion complex <b>2</b> exhibited a 2:1 (host:guest) stoichiometry in the solution, which is consistent with the result obtained from X-ray crystallography. The association of the host and guest occurred in two steps, and the association constants for the first and second steps were 1.1(7) × 10<sup>4</sup> and 1.8(5) × 10<sup>4</sup> mol<sup>−1</sup> dm<sup>3</sup>, respectively. The catalytic behavior of <b>1</b> and <b>2</b> was investigated for electrochemical hydrogen production in the aqueous solution of an acetate buffer (pH = 4.72). During the catalytic reaction, inclusion complex <b>2</b> was observed to have a better catalytic reaction rate than <b>1</b>. The study findings provide insights into the effects of the encapsulation of guest molecules within host structures.
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spelling doaj-art-c2f3f1b1cf604fedbbee3fc381d4ff8d2025-08-20T02:43:42ZengMDPI AGMolecules1420-30492024-12-012924585810.3390/molecules29245858Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen ProductionTomohiko Hamaguchi0Yuudai Iseki1Ryuta Ishikawa2Akio Mishima3Satoshi Kawata4Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, JapanDepartment of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, JapanDepartment of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, JapanDepartment of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, JapanDepartment of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, JapanIn this article, we investigate the encapsulation of K<sub>2</sub>[Ni(maleonitriledithiolate)<sub>2</sub>] (<b>1</b>) within a host molecule, β-cyclodextrin (β-CD), via single-crystal X-ray analysis. An inclusion complex, K<sub>2</sub>{[Ni(maleonitriledithiolate)<sub>2</sub>]@(β-CD)<sub>2</sub>} (<b>2</b>), was constructed from <b>1</b> and two β-CDs. The anion guest Ni complex included a host cavity, constructed using two β-CDs, and the Ni atom of the anion was located between the two hydrophilic primary rims. Ultraviolet-visible absorption spectroscopy revealed that inclusion complex <b>2</b> exhibited a 2:1 (host:guest) stoichiometry in the solution, which is consistent with the result obtained from X-ray crystallography. The association of the host and guest occurred in two steps, and the association constants for the first and second steps were 1.1(7) × 10<sup>4</sup> and 1.8(5) × 10<sup>4</sup> mol<sup>−1</sup> dm<sup>3</sup>, respectively. The catalytic behavior of <b>1</b> and <b>2</b> was investigated for electrochemical hydrogen production in the aqueous solution of an acetate buffer (pH = 4.72). During the catalytic reaction, inclusion complex <b>2</b> was observed to have a better catalytic reaction rate than <b>1</b>. The study findings provide insights into the effects of the encapsulation of guest molecules within host structures.https://www.mdpi.com/1420-3049/29/24/5858Ni complexcyclodextrininclusionelectrochemistryhydrogen evolution reaction
spellingShingle Tomohiko Hamaguchi
Yuudai Iseki
Ryuta Ishikawa
Akio Mishima
Satoshi Kawata
Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production
Molecules
Ni complex
cyclodextrin
inclusion
electrochemistry
hydrogen evolution reaction
title Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production
title_full Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production
title_fullStr Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production
title_full_unstemmed Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production
title_short Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production
title_sort structure of ni ii inclusion complex in solid solution states and the enhancement of catalytic behavior in electrochemical hydrogen production
topic Ni complex
cyclodextrin
inclusion
electrochemistry
hydrogen evolution reaction
url https://www.mdpi.com/1420-3049/29/24/5858
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