Pub Date : 2025-02-20DOI: 10.1021/acs.chemmater.4c02902
Yujin Lee, Amnon Rothman, Alexander B. Shearer, Stacey F. Bent
Area-selective atomic layer deposition (AS-ALD) has become an essential technique in precision patterning due to its ability to deposit thin films with high conformality and angstrom-level thickness control exclusively in targeted areas. This bottom-up approach offers significant advantages over conventional top-down patterning methods such as photolithography, which encounter challenges like edge placement error and require multiple processing steps. AS-ALD, with its precise control over nanostructure fabrication, supports the development of advanced devices and extends its applications to diverse fields such as sensing, catalysis, and energy. This Review considers molecular design in AS-ALD, highlighting the molecular-level interactions between atomic layer deposition (ALD) precursors and inhibitors with a focus on how variations in precursor ligands and inhibitor head and tail groups influence selectivity. Recent advancements and experimental insights are summarized to provide an understanding of the chemical mechanisms underlying AS-ALD processes. By offering detailed molecular insights, this Review aims to enhance the selection and design of precursor and inhibitor molecules, thereby advancing the development of AS-ALD across various technological fields.
{"title":"Molecular Design in Area-Selective Atomic Layer Deposition: Understanding Inhibitors and Precursors","authors":"Yujin Lee, Amnon Rothman, Alexander B. Shearer, Stacey F. Bent","doi":"10.1021/acs.chemmater.4c02902","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02902","url":null,"abstract":"Area-selective atomic layer deposition (AS-ALD) has become an essential technique in precision patterning due to its ability to deposit thin films with high conformality and angstrom-level thickness control exclusively in targeted areas. This bottom-up approach offers significant advantages over conventional top-down patterning methods such as photolithography, which encounter challenges like edge placement error and require multiple processing steps. AS-ALD, with its precise control over nanostructure fabrication, supports the development of advanced devices and extends its applications to diverse fields such as sensing, catalysis, and energy. This Review considers molecular design in AS-ALD, highlighting the molecular-level interactions between atomic layer deposition (ALD) precursors and inhibitors with a focus on how variations in precursor ligands and inhibitor head and tail groups influence selectivity. Recent advancements and experimental insights are summarized to provide an understanding of the chemical mechanisms underlying AS-ALD processes. By offering detailed molecular insights, this Review aims to enhance the selection and design of precursor and inhibitor molecules, thereby advancing the development of AS-ALD across various technological fields.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"25 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We successfully synthesized Ca-substituted B-site-ordered double perovskites La2–xCaxLiFeO6 by using high-pressure techniques and investigated site-substitution effects on the stability of unusually high valence Fe ions and their magnetic properties. Our research revealed the robust Fe5+ state against the aliovalent substitution at the A site, as seen in the actual composition La2–xCaxLiFeO6–0.5x. Introducing oxygen vacancies is a key factor in this discovery, as it significantly weakens the strong antiferromagnetic interaction for x = 0, transforming it into a weak ferromagnetic one for x > 0.3. This significant interaction change, coupled with the partial randomness of the magnetic interactions, easily releases the geometrical spin frustration of Fe5+ located on a face-centered-cubic lattice with just 5% Ca substitution. These results deepen our understanding of the site-substitution effects in geometrically frustrated B-site-ordered double perovskites.
{"title":"Robust Unusually High Valence Fe5+ State and Large Magnetic Interaction Change in the Double Perovskites La2–xCaxLiFeO6–0.5x","authors":"Masato Goto, Kazunori Sato, Wei-tin Chen, Wei-Hsiang Huang, Yuichi Shimakawa","doi":"10.1021/acs.chemmater.4c03494","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03494","url":null,"abstract":"We successfully synthesized Ca-substituted <i>B</i>-site-ordered double perovskites La<sub>2–<i>x</i></sub>Ca<i><sub><i>x</i></sub></i>LiFeO<sub>6</sub> by using high-pressure techniques and investigated site-substitution effects on the stability of unusually high valence Fe ions and their magnetic properties. Our research revealed the robust Fe<sup>5+</sup> state against the aliovalent substitution at the <i>A</i> site, as seen in the actual composition La<sub>2–<i>x</i></sub>Ca<i><sub><i>x</i></sub></i>LiFeO<sub>6–0.5<i>x</i></sub>. Introducing oxygen vacancies is a key factor in this discovery, as it significantly weakens the strong antiferromagnetic interaction for <i>x</i> = 0, transforming it into a weak ferromagnetic one for <i>x</i> > 0.3. This significant interaction change, coupled with the partial randomness of the magnetic interactions, easily releases the geometrical spin frustration of Fe<sup>5+</sup> located on a face-centered-cubic lattice with just 5% Ca substitution. These results deepen our understanding of the site-substitution effects in geometrically frustrated <i>B</i>-site-ordered double perovskites.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"31 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-20DOI: 10.1021/acs.chemmater.5c00154
Alvaro Quinteros-Sedano, Brieuc Le Besnerais, Nathan J. Van Zee, Renaud Nicolaÿ
Boronic ester-based vitrimers have garnered significant attention in the polymer science community owing to their chemical stability, ease of synthesis, and recyclability. However, like most vitrimers, these materials tend to exhibit high viscosity at high temperature, making them difficult to process. Moreover, the dynamicity of boronic ester exchange at room temperature can result in poor creep resistance under service conditions for elastomeric vitrimers. Herein, we sought to address the balance of processability and mechanical performance by exploiting dioxazaborocane groups, which are a scarcely explored class of boronic esters featuring a dative nitrogen–boron bond. Both dioxazaborocane- and dioxaborolane-based vitrimers were prepared from low glass transition temperature (Tg) polymethacrylate precursors bearing pendant complementary functional groups. Compared to dioxaborolane vitrimers, dioxazaborocane vitrimers exhibit faster relaxation dynamics at high temperatures, leading to more processable materials. The dioxazaborocane vitrimers also display improved tensile properties and competitive creep resistance, especially when using highly entangled precursors. This combination of enhanced processability and mechanical performance renders the dioxazaborocane group as an attractive motif for implementing into vitrimers.
{"title":"Exploiting Dioxazaborocane Chemistry for Preparing Elastomeric Vitrimers with Enhanced Processability and Mechanical Properties","authors":"Alvaro Quinteros-Sedano, Brieuc Le Besnerais, Nathan J. Van Zee, Renaud Nicolaÿ","doi":"10.1021/acs.chemmater.5c00154","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c00154","url":null,"abstract":"Boronic ester-based vitrimers have garnered significant attention in the polymer science community owing to their chemical stability, ease of synthesis, and recyclability. However, like most vitrimers, these materials tend to exhibit high viscosity at high temperature, making them difficult to process. Moreover, the dynamicity of boronic ester exchange at room temperature can result in poor creep resistance under service conditions for elastomeric vitrimers. Herein, we sought to address the balance of processability and mechanical performance by exploiting dioxazaborocane groups, which are a scarcely explored class of boronic esters featuring a dative nitrogen–boron bond. Both dioxazaborocane- and dioxaborolane-based vitrimers were prepared from low glass transition temperature (<i>T</i><sub>g</sub>) polymethacrylate precursors bearing pendant complementary functional groups. Compared to dioxaborolane vitrimers, dioxazaborocane vitrimers exhibit faster relaxation dynamics at high temperatures, leading to more processable materials. The dioxazaborocane vitrimers also display improved tensile properties and competitive creep resistance, especially when using highly entangled precursors. This combination of enhanced processability and mechanical performance renders the dioxazaborocane group as an attractive motif for implementing into vitrimers.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"44 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oral ulcers, prevalent lesions of the oral mucosa, often stem from trauma, viral infections, and autoimmune diseases, necessitating effective treatment strategies to address both their physical and psychological impacts. Current treatments are often limited by issues such as poor adhesion and rapid dilution within the dynamic oral environment. To overcome these challenges, we have explored the application of thermosensitive hydrogels, specifically aqueous solutions of poly(ethylene glycol)–poly(trimethylene carbonate) (PEG–PTMC) copolymers. These copolymers are noted for their biocompatibility and temperature-responsive phase transition properties. We engineered a thermosensitive drug delivery system by fine-tuning the molecular weight and segment lengths of PEG–PTMC, which gels near 32 °C and precipitates at 37 °C. Utilizing the slight temperature differential between the oral mucosa and ambient air, the system forms a Janus structure with distinct gel and precipitate layers, ensuring sustained drug release and enhanced tissue adhesion. This innovative formulation not only acts as a protective, drug-laden dressing that promotes healing but is also designed for ease of use, allowing for self-administration. This study presents a significant advancement in the treatment of oral ulcers, offering a promising solution through the in situ formation of a bilayered, drug-loaded dressing, leveraging the unique properties of thermosensitive hydrogels.
{"title":"Drug-Loaded Janus Dressings Precipitated from PEG–PTMC Thermosensitive Hydrogel for Oral Ulcer Treatment","authors":"Geng Chen, Haoming Wu, Xingchen Zhao, Zhen Zhang, Xin Hu, Peijie Hou, Chengdong Xiong, Likun Guo, Lifang Zhang","doi":"10.1021/acs.chemmater.4c03077","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03077","url":null,"abstract":"Oral ulcers, prevalent lesions of the oral mucosa, often stem from trauma, viral infections, and autoimmune diseases, necessitating effective treatment strategies to address both their physical and psychological impacts. Current treatments are often limited by issues such as poor adhesion and rapid dilution within the dynamic oral environment. To overcome these challenges, we have explored the application of thermosensitive hydrogels, specifically aqueous solutions of poly(ethylene glycol)–poly(trimethylene carbonate) (PEG–PTMC) copolymers. These copolymers are noted for their biocompatibility and temperature-responsive phase transition properties. We engineered a thermosensitive drug delivery system by fine-tuning the molecular weight and segment lengths of PEG–PTMC, which gels near 32 °C and precipitates at 37 °C. Utilizing the slight temperature differential between the oral mucosa and ambient air, the system forms a Janus structure with distinct gel and precipitate layers, ensuring sustained drug release and enhanced tissue adhesion. This innovative formulation not only acts as a protective, drug-laden dressing that promotes healing but is also designed for ease of use, allowing for self-administration. This study presents a significant advancement in the treatment of oral ulcers, offering a promising solution through the in situ formation of a bilayered, drug-loaded dressing, leveraging the unique properties of thermosensitive hydrogels.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"1 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1021/acs.chemmater.5c00053
Fei Xu, Yuyang Han, Kai Huang, Yanting Li, Qinwu Yang, Jianning Ding, Bencai Lin
A series of ether-free poly(fluorene-co-alkyl) bearing pendant piperidinium cations (PFDPE-Pi and PFDPH-Pi) was synthesized by introducing alkyl spacers into the main chain. For comparison, quaternized poly(fluorene-co-triphenyl) without alkyl spacers was prepared and characterized under the same conditions. The introduction of flexible alkyl spacers imparted excellent flexibility, high water uptake, and high conductivity to the PFDPE-Pi and PFDPH-Pi membranes. Notably, the conductivity of PFDPH-Pi decreased by only 4% after immersion in 2 M KOH at 80 °C for 30 days, indicating its excellent alkaline stability. The H2/O2 anion exchange membrane fuel cell with PFDPH-Pi exhibited a peak power density of 698 mW cm–2, which was significantly higher than that of 484 mW cm–2 observed for the cells with PFTP-Pi. This study provides an effective approach for preparing durable polyfluorene-based anion exchange membranes with satisfactory comprehensive performance, highlighting their potential for fuel cell applications.
{"title":"Poly(fluorene-co-alkyl)-based Polymers Bearing Pendant Piperidinium Cations for Alkaline Anion Exchange Membrane Fuel Cell Applications","authors":"Fei Xu, Yuyang Han, Kai Huang, Yanting Li, Qinwu Yang, Jianning Ding, Bencai Lin","doi":"10.1021/acs.chemmater.5c00053","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c00053","url":null,"abstract":"A series of ether-free poly(fluorene-<i>co</i>-alkyl) bearing pendant piperidinium cations (PFDPE-Pi and PFDPH-Pi) was synthesized by introducing alkyl spacers into the main chain. For comparison, quaternized poly(fluorene-<i>co</i>-triphenyl) without alkyl spacers was prepared and characterized under the same conditions. The introduction of flexible alkyl spacers imparted excellent flexibility, high water uptake, and high conductivity to the PFDPE-Pi and PFDPH-Pi membranes. Notably, the conductivity of PFDPH-Pi decreased by only 4% after immersion in 2 M KOH at 80 °C for 30 days, indicating its excellent alkaline stability. The H<sub>2</sub>/O<sub>2</sub> anion exchange membrane fuel cell with PFDPH-Pi exhibited a peak power density of 698 mW cm<sup>–2</sup>, which was significantly higher than that of 484 mW cm<sup>–2</sup> observed for the cells with PFTP-Pi. This study provides an effective approach for preparing durable polyfluorene-based anion exchange membranes with satisfactory comprehensive performance, highlighting their potential for fuel cell applications.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"14 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1021/acs.chemmater.4c02817
Alexandru B. Georgescu
While adding charge to semiconductors via dopants is a well-established method for tuning electronic properties, we demonstrate that introducing transition-metal impurities into certain insulators can lead to localized charge, assisted by a Jahn–Teller distortion. This leads to isolated charge and an insulating material, as opposed to emergent states, including superconductivity. We focus on Cu impurities added to Pb10(PO4)6O (“LK-99”), replacing 10% of Cu ions, as discussed in recent literature. Our calculations show that the material remains a wide bandgap insulator with isolated, S = 1/2 localized charges on the Cu ions─similar to color centers, even within standard DFT, without the need for electron correlation corrections to the Cu d-orbitals. Superconductivity is excluded by known mechanisms that require the material to be metallic. We resolve previously observed inconsistencies between density functional theory results and experimental findings related to doping site energetics, crystal structure, and transparency. We find that Cu doping either Pb site leads to CuO4 coordination and a similar unit cell volume contraction. Engineering materials with dopant sites that have different local symmetries can induce nonrelativistic spin splitting─often referred to as altermagnetism. However, in the case of localized charges, this may enable spins to be individually controlled.
{"title":"Why Charge Added Using Transition Metals to Some Insulators, Including LK-99, Localizes and Does Not Yield a Metal","authors":"Alexandru B. Georgescu","doi":"10.1021/acs.chemmater.4c02817","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02817","url":null,"abstract":"While adding charge to semiconductors via dopants is a well-established method for tuning electronic properties, we demonstrate that introducing transition-metal impurities into certain insulators can lead to localized charge, assisted by a Jahn–Teller distortion. This leads to isolated charge and an insulating material, as opposed to emergent states, including superconductivity. We focus on Cu impurities added to Pb<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>O (“LK-99”), replacing 10% of Cu ions, as discussed in recent literature. Our calculations show that the material remains a wide bandgap insulator with isolated, <i>S</i> = 1/2 localized charges on the Cu ions─similar to color centers, even within standard DFT, without the need for electron correlation corrections to the Cu d-orbitals. Superconductivity is excluded by known mechanisms that require the material to be metallic. We resolve previously observed inconsistencies between density functional theory results and experimental findings related to doping site energetics, crystal structure, and transparency. We find that Cu doping either Pb site leads to CuO<sub>4</sub> coordination and a similar unit cell volume contraction. Engineering materials with dopant sites that have different local symmetries can induce nonrelativistic spin splitting─often referred to as altermagnetism. However, in the case of localized charges, this may enable spins to be individually controlled.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"25 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143451994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Covalent organic frameworks (COFs) have recently demonstrated significant potential for photocatalysis. Optimizing the local electronic environment in COFs has been considered to be critical for enhancing photocatalytic activity. Here, we report a one-pot “grafting-to” strategy to reprogram the local electronic configurations of a series of isoreticular multicomponent COFs by introducing electron-donating or electron-withdrawing groups into the pores to transform photoinert to photoactive COFs and form intramolecular donor–acceptor (D-A) structures. Such D-A structures enhanced the overall hydrogen peroxide photoproduction by facilitating charge carrier separation and optimizing band structures to achieve the oxygen reduction reaction and water oxidation reaction simultaneously. Notably, the one incorporated with 2-aminothiazole exhibits a hydrogen peroxide production rate of 3701 μmol g–1 h–1 and solar-to-chemical conversion efficiency of 0.13% without the use of any sacrificial reagents, and it exhibits 100% bacterial killing rates and a remarkable >90% biofilm removal capability. This “grafting-to” COF modification strategy, which has not been reported before, offers a unique approach for constructing highly active COF photocatalysts containing intramolecular D-A structures and exhibits great potential in the future design of photocatalysts and antibacterial therapies.
{"title":"Reprogram Local Electronic Configuration in Multicomponent Covalent–Organic Frameworks for Efficient Hydrogen Peroxide Photoproduction","authors":"Zhaoyue Ding, Jiani Yang, Zihe Wu, Mohsen Adeli, Xianglin Luo, Xiaolin Wang, Xiaodong Xie, Xiaohui Xu, Chong Cheng, Changsheng Zhao","doi":"10.1021/acs.chemmater.4c03325","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03325","url":null,"abstract":"Covalent organic frameworks (COFs) have recently demonstrated significant potential for photocatalysis. Optimizing the local electronic environment in COFs has been considered to be critical for enhancing photocatalytic activity. Here, we report a one-pot “grafting-to” strategy to reprogram the local electronic configurations of a series of isoreticular multicomponent COFs by introducing electron-donating or electron-withdrawing groups into the pores to transform photoinert to photoactive COFs and form intramolecular donor–acceptor (D-A) structures. Such D-A structures enhanced the overall hydrogen peroxide photoproduction by facilitating charge carrier separation and optimizing band structures to achieve the oxygen reduction reaction and water oxidation reaction simultaneously. Notably, the one incorporated with 2-aminothiazole exhibits a hydrogen peroxide production rate of 3701 μmol g<sup>–1</sup> h<sup>–1</sup> and solar-to-chemical conversion efficiency of 0.13% without the use of any sacrificial reagents, and it exhibits 100% bacterial killing rates and a remarkable >90% biofilm removal capability. This “grafting-to” COF modification strategy, which has not been reported before, offers a unique approach for constructing highly active COF photocatalysts containing intramolecular D-A structures and exhibits great potential in the future design of photocatalysts and antibacterial therapies.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"7 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1021/acs.chemmater.5c00049
Nitul Kalita, Jagnyesh K. Satpathy, Rolly Yadav, Chivukula V. Sastri, Mohammad Qureshi
This study investigates the integration of two geometrically distinct nickel complexes with a heterogeneous catalytic counterpart to enhance the water oxidation performance. Bispidine-based Ni(II) complexes with a flexible backbone, NiL1Flex, and a rigid backbone, NiL2Rigid, act as homogeneous catalysts, whereas β-Ni(OH)2@NF nanoflowers serve as a heterogeneous catalyst counterpart. NiL2Rigid, featuring an octahedral geometry, exhibits superior electrocatalytic performance with an overpotential of 330 mV at 10 mA/cm2 and a Tafel slope of 97 mV/dec in 0.1 M phosphate buffer solution (pH 7), outperforming NiL1Flex with a distorted tetrahedral geometry. Single-crystal XRD reveals that the octahedral geometry with cis-positioned labile water sites of NiL2Rigid promotes O–O coupling for O2 generation, explaining its lower overpotential and enhanced charge transfer kinetics compared to the distorted tetrahedral NiL1Flex complex, which is devoid of such attached cis-labile water molecules. The enhanced activity of NiL2Rigid is attributed to its minimized potential difference across the redox couple (Ni2+/Ni3+), aiding favorable synchronization among homogeneous and heterogeneous catalytic systems. Mullikan spin density calculations reveal that the rigid complex NiL2Rigid has a highly localized spin density (∼80%) on the nickel center, whereas the spin density population mainly lies between the metal and oxygen bonds in NiL1Flex reducing the redox activity of nickel in a flexible backbone. This research work establishes a model system that integrates homogeneous and heterogeneous catalysis for efficient water oxidation, leveraging the advantages of both systems while addressing their limitations through their integration.
{"title":"Integrating Homogeneous and Heterogeneous Catalytic Systems for Synergistic Water Oxidation: Role of Geometrically Distinct Bispidine Metal Complexes","authors":"Nitul Kalita, Jagnyesh K. Satpathy, Rolly Yadav, Chivukula V. Sastri, Mohammad Qureshi","doi":"10.1021/acs.chemmater.5c00049","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c00049","url":null,"abstract":"This study investigates the integration of two geometrically distinct nickel complexes with a heterogeneous catalytic counterpart to enhance the water oxidation performance. Bispidine-based Ni(II) complexes with a flexible backbone, <b>Ni</b><sub><b>L1</b></sub><sup><b>Flex</b></sup>, and a rigid backbone, <b>Ni</b><sub><b>L2</b></sub><sup><b>Rigid</b></sup>, act as homogeneous catalysts, whereas β-Ni(OH)<sub>2</sub>@NF nanoflowers serve as a heterogeneous catalyst counterpart. <b>Ni</b><sub><b>L2</b></sub><sup><b>Rigid</b></sup>, featuring an octahedral geometry, exhibits superior electrocatalytic performance with an overpotential of 330 mV at 10 mA/cm<sup>2</sup> and a Tafel slope of 97 mV/dec in 0.1 M phosphate buffer solution (pH 7), outperforming <b>Ni</b><sub><b>L1</b></sub><sup><b>Flex</b></sup> with a distorted tetrahedral geometry. Single-crystal XRD reveals that the octahedral geometry with cis-positioned labile water sites of <b>Ni</b><sub><b>L2</b></sub><sup><b>Rigid</b></sup> promotes O–O coupling for O<sub>2</sub> generation, explaining its lower overpotential and enhanced charge transfer kinetics compared to the distorted tetrahedral <b>Ni</b><sub><b>L1</b></sub><sup><b>Flex</b></sup> complex, which is devoid of such attached cis-labile water molecules. The enhanced activity of <b>Ni</b><sub><b>L2</b></sub><sup><b>Rigid</b></sup> is attributed to its minimized potential difference across the redox couple (Ni<sup>2+</sup>/Ni<sup>3+</sup>), aiding favorable synchronization among homogeneous and heterogeneous catalytic systems. Mullikan spin density calculations reveal that the rigid complex <b>Ni</b><sub><b>L2</b></sub><sup><b>Rigid</b></sup> has a highly localized spin density (∼80%) on the nickel center, whereas the spin density population mainly lies between the metal and oxygen bonds in <b>Ni</b><sub><b>L1</b></sub><sup><b>Flex</b></sup> reducing the redox activity of nickel in a flexible backbone. This research work establishes a model system that integrates homogeneous and heterogeneous catalysis for efficient water oxidation, leveraging the advantages of both systems while addressing their limitations through their integration.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"28 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-19DOI: 10.1021/acs.chemmater.4c03411
Dominic Cudjoe Asebiah, Autumn N. Peters, Lauren Borgia, Adair Nicolson, David O. Scanlon, Obadiah G. Reid, James R. Neilson
Ordering vacancies in hybrid Sn(II) halide semiconductors provides a strategy for preventing uncontrolled oxidation and formation of mobile holes. In this study, we report the structure and optical and electronic properties of (NH3(CH2)7NH3)2Sn3I10, a vacancy-ordered perovskite derivative with three-dimensional inorganic connectivity. The crystal structure resembles that of a Dion–Jacobson layered perovskite derivative, but with [SnI5] square pyramids bridging the layers. UV–vis diffuse reflectance spectroscopy reveals a sharp onset of light absorption at 1.86(1) eV with the photoluminescence emission maximum at 1.90(1) eV. However, the maximum excitation occurs from 3.42 to 3.81 eV (325 to 370 nm), revealing a significant Stokes shift of 1.3 eV. The electronic properties determined from dark and time-resolved microwave conductivity measurements reveal a minimum carrier mobility of 4.3 × 10–2 cm2 V–1 s–1 and a maximum carrier density of 5.96 × 1016 cm–3, a uniquely low value for a hybrid Sn(II) halide semiconductor. The transport behavior in combination with first-principles calculations of the electronic band structure and dielectric permittivity suggest polaron-mediated electronic transport, yet the photogenerated carriers have a fast and fluence-dependent nonradiative recombination rate, suggestive of localized “defect-like” states at the band edge. The observed photoluminescence is most consistent with single-ion-like behavior of an asymmetric Sn(II) environment. Together, these results suggest that defect ordering presents a strategy for the reduction of mobile charge carriers at equilibrium.
{"title":"(NH3(CH2)7NH3)2Sn3I10, a Vacancy-Ordered Three-Dimensional Tin(II) Perovskite-Derived Semiconductor","authors":"Dominic Cudjoe Asebiah, Autumn N. Peters, Lauren Borgia, Adair Nicolson, David O. Scanlon, Obadiah G. Reid, James R. Neilson","doi":"10.1021/acs.chemmater.4c03411","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03411","url":null,"abstract":"Ordering vacancies in hybrid Sn(II) halide semiconductors provides a strategy for preventing uncontrolled oxidation and formation of mobile holes. In this study, we report the structure and optical and electronic properties of (NH<sub>3</sub>(CH<sub>2</sub>)<sub>7</sub>NH<sub>3</sub>)<sub>2</sub>Sn<sub>3</sub>I<sub>10</sub>, a vacancy-ordered perovskite derivative with three-dimensional inorganic connectivity. The crystal structure resembles that of a Dion–Jacobson layered perovskite derivative, but with [SnI<sub>5</sub>] square pyramids bridging the layers. UV–vis diffuse reflectance spectroscopy reveals a sharp onset of light absorption at 1.86(1) eV with the photoluminescence emission maximum at 1.90(1) eV. However, the maximum excitation occurs from 3.42 to 3.81 eV (325 to 370 nm), revealing a significant Stokes shift of 1.3 eV. The electronic properties determined from dark and time-resolved microwave conductivity measurements reveal a minimum carrier mobility of 4.3 × 10<sup>–2</sup> cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> and a maximum carrier density of 5.96 × 10<sup>16</sup> cm<sup>–3</sup>, a uniquely low value for a hybrid Sn(II) halide semiconductor. The transport behavior in combination with first-principles calculations of the electronic band structure and dielectric permittivity suggest polaron-mediated electronic transport, yet the photogenerated carriers have a fast and fluence-dependent nonradiative recombination rate, suggestive of localized “defect-like” states at the band edge. The observed photoluminescence is most consistent with single-ion-like behavior of an asymmetric Sn(II) environment. Together, these results suggest that defect ordering presents a strategy for the reduction of mobile charge carriers at equilibrium.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"31 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18DOI: 10.1021/acs.chemmater.4c03359
Felipe Quiroga-Suavita, Victor Varela-Izquierdo, Teresa Hungria, Damien Alloyeau, Nicolas Ratel-Ramond, Simon Cayez, Richard D. Tilley, Edwin A. Baquero, Bruno Chaudret, Lise-Marie Lacroix
The development of bimetallic nanomaterials with precisely controlled size, shape, and composition has emerged as a cornerstone of sustainable catalysis, offering innovative solutions for chemical valorization processes. In this work, CoPd bimetallic nanoparticles were prepared via an organometallic approach using Co[N(SiMe3)2]2(thf) and Pd(acac)2 (acac: acetylacetonate) as metal sources. Advanced structural characterization techniques, including high-resolution transmission electron microscopy, X-ray diffraction, and wide-angle X-ray scattering, revealed an icosahedral Pd-rich core with a less crystalline Co-rich shell. Thanks to a large magnetic anisotropy, these 10 nm particles are ferromagnetic at room temperature and thus can be used as efficient heating agents under an alternative magnetic field. This nanomaterial was successfully tested as a catalyst in hydrodeoxygenation reactions using induction heating for energy-efficient activation. The CoPd catalyst demonstrates the synergistic potential of the non-noble/noble metal combination, achieving challenging chemical transformations at relatively low temperatures while keeping an optimal balance between their heating capability and surface-to-volume ratio. This study underscores the potential of CoPd systems for advancing sustainable catalysis through magnetically induced reactions.
{"title":"Icosahedra CoPd Bimetallic Nanoparticles for Magnetically Induced Aromatic Ketone Hydrodeoxygenation","authors":"Felipe Quiroga-Suavita, Victor Varela-Izquierdo, Teresa Hungria, Damien Alloyeau, Nicolas Ratel-Ramond, Simon Cayez, Richard D. Tilley, Edwin A. Baquero, Bruno Chaudret, Lise-Marie Lacroix","doi":"10.1021/acs.chemmater.4c03359","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03359","url":null,"abstract":"The development of bimetallic nanomaterials with precisely controlled size, shape, and composition has emerged as a cornerstone of sustainable catalysis, offering innovative solutions for chemical valorization processes. In this work, CoPd bimetallic nanoparticles were prepared via an organometallic approach using Co[N(SiMe<sub>3</sub>)<sub>2</sub>]<sub>2</sub>(thf) and Pd(acac)<sub>2</sub> (acac: acetylacetonate) as metal sources. Advanced structural characterization techniques, including high-resolution transmission electron microscopy, X-ray diffraction, and wide-angle X-ray scattering, revealed an icosahedral Pd-rich core with a less crystalline Co-rich shell. Thanks to a large magnetic anisotropy, these 10 nm particles are ferromagnetic at room temperature and thus can be used as efficient heating agents under an alternative magnetic field. This nanomaterial was successfully tested as a catalyst in hydrodeoxygenation reactions using induction heating for energy-efficient activation. The CoPd catalyst demonstrates the synergistic potential of the non-noble/noble metal combination, achieving challenging chemical transformations at relatively low temperatures while keeping an optimal balance between their heating capability and surface-to-volume ratio. This study underscores the potential of CoPd systems for advancing sustainable catalysis through magnetically induced reactions.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"81 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143443899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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