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Dutt S, Kottaichamy AR, Dargily NC, Mukhopadhyay S, Nayak B, Devendrachari MC, Vinod CP, Nimbegondi Kotresh HM, Ottakam Thotiyl M. Switchable molecular electrocatalysis. Chem Sci 2024; 15:13262-13270. [PMID: 39183932 PMCID: PMC11339944 DOI: 10.1039/d4sc01284d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 07/04/2024] [Indexed: 08/27/2024] Open
Abstract
We demonstrate a switchable electrocatalysis mechanism modulated by hydrogen bonding interactions in ligand geometries. By manipulating these geometries, specific electrochemical processes at a single catalytic site can be selectively and precisely activated or deactivated. The α geometry enhances dioxygen electroreduction (ORR) while inhibiting protium redox processes, with the opposite effect seen in the β geometry. Intramolecular hydrogen bonding in the α geometry boosts electron density at the catalytic center, facilitating a shift of ORR to a 4-electron pathway. Conversely, the β geometry promotes a 2-electron ORR and facilitates electrocatalytic hydrogen evolution through an extensive proton charge assembly; offering a paradigm shift to conventional electrocatalytic principles. The expectations that ligand geometry induced electron density modulations in the catalytic metal centre would have a comparable impact on both ORR and HER has been questioned due to the contrasting reactivity exhibited by α-geometry and β-geometry molecules. This further emphasizes the complex and intriguing nature of the roles played by ligands in molecular electrocatalysis.
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Affiliation(s)
- Shifali Dutt
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune Dr Homi Bhabha Road, Pashan Pune 411008 Maharashtra India
| | - Alagar Raja Kottaichamy
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune Dr Homi Bhabha Road, Pashan Pune 411008 Maharashtra India
- Department of Chemistry, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev Beer-Sheva 8410501 Israel
| | - Neethu Christudas Dargily
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune Dr Homi Bhabha Road, Pashan Pune 411008 Maharashtra India
| | - Sanchayita Mukhopadhyay
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune Dr Homi Bhabha Road, Pashan Pune 411008 Maharashtra India
| | - Bhojkumar Nayak
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune Dr Homi Bhabha Road, Pashan Pune 411008 Maharashtra India
| | | | | | | | - Musthafa Ottakam Thotiyl
- Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune Dr Homi Bhabha Road, Pashan Pune 411008 Maharashtra India
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Kottaichamy AR, Nazrulla MA, Parmar M, Thimmappa R, Devendrachari MC, Vinod CP, Volokh M, Kotresh HMN, Shalom M, Thotiyl MO. Ligand Isomerization Driven Electrocatalytic Switching. Angew Chem Int Ed Engl 2024; 63:e202405664. [PMID: 38695160 DOI: 10.1002/anie.202405664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Indexed: 06/21/2024]
Abstract
The prevailing view about molecular catalysts is that the central metal ion is responsible for the reaction mechanism and selectivity, whereas the ligands mainly affect the reaction kinetics. Here, we question this paradigm and show that ligands have a dramatic influence on the selectivity of the product. We show how even a seemingly small change in ligand isomerization sharply alters the selectivity of the well-researched oxygen reduction reaction (ORR) Co phthalocyanine catalyst from an indirect 2e- to a direct 4e- pathway. Detailed analysis reveals that intramolecular hydrogen-bond interactions in the ligand activate the catalytic Co, directing the oxygen binding and thus deciding the final product. The resulting catalyst is the first example of a Co-based molecular catalyst catalyzing a direct 4e- ORR via ligand isomerization, for which it shows an activity close to the benchmark Pt in an actual H2-O2 fuel cell. The effect of the ligand isomerism is demonstrated with different central metal ions, thus highlighting the generalizability of the findings and their potential to open new possibilities in the design of molecular catalysts.
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Affiliation(s)
- Alagar Raja Kottaichamy
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | | | - Muskan Parmar
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Ravikumar Thimmappa
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | | | | | - Michael Volokh
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | | | - Menny Shalom
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Musthafa Ottakam Thotiyl
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
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Mukhopadhyay S, Kottaichamy AR, Devendrachari MC, Mendhe RM, Nimbegondi Kotresh HM, Vinod CP, Ottakam Thotiyl M. Electrochemical energy storage in an organic supercapacitor via a non-electrochemical proton charge assembly. Chem Sci 2024; 15:1726-1735. [PMID: 38303938 PMCID: PMC10829031 DOI: 10.1039/d3sc05639b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 12/18/2023] [Indexed: 02/03/2024] Open
Abstract
Contrary to conventional beliefs, we show how a functional ligand that does not exhibit any redox activity elevates the charge storage capability of an electric double layer via a proton charge assembly. Compared to an unsubstituted ligand, a non-redox active carboxy ligand demonstrated nearly a 4-fold increase in charge storage, impressive capacitive retention even at a rate of 900C, and approximately a 2-fold decrease in leakage currents with an enhancement in energy density up to approximately 70% via a non-electrochemical route of proton charge assembly. Generalizability of these findings is presented with various non-redox active functional units that can undergo proton charge assembly in the ligand. This demonstration of non-redox active functional units enriching supercapacitive charge storage via proton charge assembly contributes to the rational design of ligands for energy storage applications.
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Affiliation(s)
- Sanchayita Mukhopadhyay
- Department of Chemistry, Indian Institute of Science Education and Research, Pune Dr Homi Bhabha Road Pune 411008 India
| | - Alagar Raja Kottaichamy
- Department of Chemistry, Indian Institute of Science Education and Research, Pune Dr Homi Bhabha Road Pune 411008 India
- Department of Chemistry, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev Beer-Sheva 8410501 Israel
| | | | - Rahul Mahadeo Mendhe
- Department of Chemistry, Indian Institute of Science Education and Research, Pune Dr Homi Bhabha Road Pune 411008 India
| | | | | | - Musthafa Ottakam Thotiyl
- Department of Chemistry, Indian Institute of Science Education and Research, Pune Dr Homi Bhabha Road Pune 411008 India
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Kottaichamy AR, Deebansok S, Deng J, Nazrulla MA, Zhu Y, Bhat ZM, Devendrachari MC, Vinod CP, Nimbegondi Kotresh HM, Fontaine O, Thotiyl MO. Unprecedented energy storage in metal-organic complexes via constitutional isomerism. Chem Sci 2023; 14:6383-6392. [PMID: 37325136 PMCID: PMC10266471 DOI: 10.1039/d3sc01692g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023] Open
Abstract
The essence of any electrochemical system is engraved in its electrical double layer (EDL), and we report its unprecedented reorganization by the structural isomerism of molecules, with a direct consequence on their energy storage capability. Electrochemical and spectroscopic analyses in combination with computational and modelling studies demonstrate that an attractive field-effect due to the molecule's structural-isomerism, in contrast to a repulsive field-effect, spatially screens the ion-ion coulombic repulsions in the EDL and reconfigures the local density of anions. In a laboratory-level prototype supercapacitor, those with β-structural isomerism exhibit nearly 6-times elevated energy storage compared to the state-of-the-art electrodes, by delivering ∼535 F g-1 at 1 A g-1 while maintaining high performance metrics even at a rate as high as 50 A g-1. The elucidation of the decisive role of structural isomerism in reconfiguring the electrified interface represents a major step forward in understanding the electrodics of molecular platforms.
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Affiliation(s)
- Alagar Raja Kottaichamy
- Indian Institute of Science Education and Research (IISER) Pune Dr Homi Bhabha Road Pashan Pune 411008 India
| | | | - Jie Deng
- Institute for Advanced Study, College of Food and Biological Engineering, Chengdu University Chengdu 610106 China
| | | | - Yachao Zhu
- ICGM, Univ. Montpellier, CNRS, ENSCM Montpellier France
| | - Zahid Manzoor Bhat
- Indian Institute of Science Education and Research (IISER) Pune Dr Homi Bhabha Road Pashan Pune 411008 India
| | | | | | | | - Olivier Fontaine
- Molecular Electrochemistry for Energy Laboratory, VISTEC Rayong 21210 Thailand
- Institut Universitaire de France 75005 Paris France
| | - Musthafa Ottakam Thotiyl
- Indian Institute of Science Education and Research (IISER) Pune Dr Homi Bhabha Road Pashan Pune 411008 India
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Majeed SA, Sekhosana KE, Tuhl A. Progress on phthalocyanine-conjugated Ag and Au nanoparticles: Synthesis, characterization, and photo-physicochemical properties. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2020.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Peteni S, Nyokong T. Effect of doping vs covalent linking of a low symmetry zinc phthalocyanine to silica nanoparticles on singlet oxygen production. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.06.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Nwaji N, Jones B, Mack J, Oluwole DO, Nyokong T. Nonlinear optical dynamics of benzothiazole derivatized phthalocyanines in solution, thin films and when conjugated to nanoparticles. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2017.05.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bankole OM, Nyokong T. Azide-derivatized gold nanosphere “clicked” to indium and zinc phthalocyanines for improved nonlinear optical limiting. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.01.088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Enhanced nonlinear optical responses of zinc diaminopyrimidin-2-ylthio phthalocyanine conjugated to AgxAuy alloy nanoparticles. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.06.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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