Magnetic field-dependent magnetization of highly crystalline Fe3O4 magnetic nanoparticles has been carried out to understand surface canting structures at low and room temperatures. The exchange bias (HEB) values of ∼18 to 27 Oe at 300 K for three samples prepared from different precursors are observed; and a decrease in value is obtained when the samples are measured at 5 K. However, with a decrease in temperature, coercivity (Hc) increases. This is related to an increase in the percentage of magnetization in the core of the particles and a decrease in the percentage of antiferromagnetic contribution on the surface of the particles when the sample is cooled from 300 K to 5 K. At low concentrations of magnetic particles and low power of the alternating current (AC) magnetic field, heat generation from the three samples is found to vary. In the case of high concentrations of magnetic particles and high power of the AC magnetic field, heat generation from the samples is almost the same. This is due to the saturation of AC magnetic field absorption by the magnetic nanoparticles at such high power and high concentration, irrespective of the samples. These findings are very interesting. The microstructures of the magnetic nanoparticles are studied through tilting from 0° to 14°. Agglomeration, non-agglomeration, porosity, etc. can be distinguished. From dark field (DF) and bright field (BF) images, we were able to resolve many mysterious microstructures, without which many properties would be interpreted wrongly.
{"title":"Heat-generation behavior of Fe3O4 particles in AC magnetic fields: analysis of microstructures through tilting","authors":"Manas Srivastava, Ruchi Agrawal, Atom Rajiv Singh, Leishangthem Sanatombi Devi, Rashmi Joshi, Bheeshma Pratap Singh, D. Sarkar, Rakesh Kumar Singhal, Raghumani Singh Ningthoujam","doi":"10.1039/d4dt02448f","DOIUrl":"https://doi.org/10.1039/d4dt02448f","url":null,"abstract":"Magnetic field-dependent magnetization of highly crystalline Fe<small><sub>3</sub></small>O<small><sub>4</sub></small> magnetic nanoparticles has been carried out to understand surface canting structures at low and room temperatures. The exchange bias (<em>H</em><small><sub>EB</sub></small>) values of ∼18 to 27 Oe at 300 K for three samples prepared from different precursors are observed; and a decrease in value is obtained when the samples are measured at 5 K. However, with a decrease in temperature, coercivity (<em>H</em><small><sub>c</sub></small>) increases. This is related to an increase in the percentage of magnetization in the core of the particles and a decrease in the percentage of antiferromagnetic contribution on the surface of the particles when the sample is cooled from 300 K to 5 K. At low concentrations of magnetic particles and low power of the alternating current (AC) magnetic field, heat generation from the three samples is found to vary. In the case of high concentrations of magnetic particles and high power of the AC magnetic field, heat generation from the samples is almost the same. This is due to the saturation of AC magnetic field absorption by the magnetic nanoparticles at such high power and high concentration, irrespective of the samples. These findings are very interesting. The microstructures of the magnetic nanoparticles are studied through tilting from 0° to 14°. Agglomeration, non-agglomeration, porosity, <em>etc</em>. can be distinguished. From dark field (DF) and bright field (BF) images, we were able to resolve many mysterious microstructures, without which many properties would be interpreted wrongly.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"31 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rosa Maria Dell'Acqua, Francesco Fagnani, Monika Wojciechowska, Daniele Marinotto, Graziano Colombo, Isabella Delle Donne, Joanna Trylska, Silvia Cauteruccio, Alessia Colombo
The synthesis of novel highly phosphorescent N^C^N tridentate platinum(II)-complex-peptide nucleic acid (PNA) bioconjugates was accomplished through the solid-phase approach. Melting temperature measurements and circular dichroism spectroscopy studies demonstrated that these conjugates maintain the PNA ability to recognize complementary ssDNA and ssRNA, though the length of the spacer between the metal center and the PNA sequence affects their hybridization properties. Noteworthy, the conjugation of PNA to this family of Pt(II) complexes significantly enhanced the luminescent features of the organometallic moiety, leading to increased quantum yields (82.8%, 105 M), even in the presence of oxygen (48.6%, 105 M). An in vitro cytotoxicity study of Pt(II)-PNA conjugates on HeLa cells showed no significative effect on cell growth in the dark (1 μM for 72 h).
{"title":"Highly phosphorescent N^C^N platinum(II)-peptide nucleic acid conjugates: synthesis, photophysical studies and hybridization behaviour","authors":"Rosa Maria Dell'Acqua, Francesco Fagnani, Monika Wojciechowska, Daniele Marinotto, Graziano Colombo, Isabella Delle Donne, Joanna Trylska, Silvia Cauteruccio, Alessia Colombo","doi":"10.1039/d4dt03366c","DOIUrl":"https://doi.org/10.1039/d4dt03366c","url":null,"abstract":"The synthesis of novel highly phosphorescent N^C^N tridentate platinum(II)-complex-peptide nucleic acid (PNA) bioconjugates was accomplished through the solid-phase approach. Melting temperature measurements and circular dichroism spectroscopy studies demonstrated that these conjugates maintain the PNA ability to recognize complementary ssDNA and ssRNA, though the length of the spacer between the metal center and the PNA sequence affects their hybridization properties. Noteworthy, the conjugation of PNA to this family of Pt(II) complexes significantly enhanced the luminescent features of the organometallic moiety, leading to increased quantum yields (82.8%, 105 M), even in the presence of oxygen (48.6%, 105 M). An in vitro cytotoxicity study of Pt(II)-PNA conjugates on HeLa cells showed no significative effect on cell growth in the dark (1 μM for 72 h).","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"52 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photocatalytic degradation of the azo dye orange II using NdVO4/V2O5/BiVO4 under visible light is reported here, and this oxygen-rich defect three-phase heterojunction structure is constructed using a two-step cation exchange method. This heterojunction significantly enhances the separation and migration efficiency of photo-induced charges, while the accompanying oxygen defects effectively capture photogenerated electrons, thereby suppressing the recombination of electrons and holes. Experimental characterization and theoretical calculations demonstrate the efficient separation and transfer capabilities of photogenerated carriers and their excellent photocatalytic degradation performance. Particularly, when treating the anionic dye orange II, this heterojunction structure achieves a degradation efficiency of up to 96.15%. Cycling tests show that NVB-24 exhibits good stability during the reaction process. This research provides a promising photocatalyst for the efficient degradation of anionic azo dyes and offers new insights for developing high-quality photocatalytic materials.
{"title":"Synthesis of a three-phase heterojunction NdVO4/V2O5/BiVO4 by cation exchange method for the degradation of anionic azo dye orange II","authors":"Liyang Li, Zixi Liao, Jianhong Yi, Dong Fang","doi":"10.1039/d4dt03092c","DOIUrl":"https://doi.org/10.1039/d4dt03092c","url":null,"abstract":"Photocatalytic degradation of the azo dye orange II using NdVO<small><sub>4</sub></small>/V<small><sub>2</sub></small>O<small><sub>5</sub></small>/BiVO<small><sub>4</sub></small> under visible light is reported here, and this oxygen-rich defect three-phase heterojunction structure is constructed using a two-step cation exchange method. This heterojunction significantly enhances the separation and migration efficiency of photo-induced charges, while the accompanying oxygen defects effectively capture photogenerated electrons, thereby suppressing the recombination of electrons and holes. Experimental characterization and theoretical calculations demonstrate the efficient separation and transfer capabilities of photogenerated carriers and their excellent photocatalytic degradation performance. Particularly, when treating the anionic dye orange II, this heterojunction structure achieves a degradation efficiency of up to 96.15%. Cycling tests show that NVB-24 exhibits good stability during the reaction process. This research provides a promising photocatalyst for the efficient degradation of anionic azo dyes and offers new insights for developing high-quality photocatalytic materials.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"36 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reaction between [VO(acac)2] and two valproic acid hydrazide ligands, H2L1 and H2L2 leads to the formation of two mononuclear dioxido complexes [VV(O2)HL1-2] (1, 2) in acetonitrile, two oxidomethoxido complexes [VVO(L1-2)(OMe)(OHMe)] (3, 4) in methanol and the corresponding dinuclear μ-oxidodivanadium complexes [{VVOL1-2}2 μ -O] (5, 6) in dichloromethane. Here H2L1 is valproic acid hydrazone of salicylaldehyde and H2L2 is that of 2-hydroxy naphthaldehyde. X-ray crystallographic studies revealed the dual binding mode of the ligands e.g. neutral amido form in dioxoido complex 1 and dianionic iminolato form the oxidomethoxido complex 3. The redox behaviour of all the complexes were investigated using a combination of experimental and theoretical approaches. Partial reduction of 5, 6 by constant potential electrolysis (CPE) conforming to a Robin–Day type II mixed-valence species 5a and 6a of general formula (L)(O)VIV−O−VV(O)(L). The Complexes catalytically oxidized pyrogallol to purpurogallin and catechol like system to quinone under ambient condition. Catecholase like activity was found to follow a very rare semiquinone radical intermediate for vanadium model system.
{"title":"New VVO2,VVO, VVOVVO and electrogenerated VIVOVVO systems of valproic acid hydrazones: Study of catalytic activity","authors":"Roumi Patra, Debopam Sinha, Sandip Mondal, Kajal Krishna Rajak","doi":"10.1039/d4dt02030h","DOIUrl":"https://doi.org/10.1039/d4dt02030h","url":null,"abstract":"Reaction between [VO(acac)<small><sub>2</sub></small>] and two valproic acid hydrazide ligands, H<small><sub>2</sub></small>L<small><sup>1</sup></small> and H<small><sub>2</sub></small>L<small><sup>2</sup></small> leads to the formation of two mononuclear dioxido complexes [V<small><sup>V</sup></small>(O<small><sub>2</sub></small>)HL<small><sup>1-2</sup></small>] (<strong>1</strong>, <strong>2</strong>) in acetonitrile, two oxidomethoxido complexes [V<small><sup>V</sup></small>O(L<small><sup>1-2</sup></small>)(OMe)(OHMe)] (<strong>3</strong>, <strong>4</strong>) in methanol and the corresponding dinuclear μ-oxidodivanadium complexes [{V<small><sup>V</sup></small>OL<small><sup>1-2</sup></small>}<small><sub>2</sub></small> μ -O] (<strong>5</strong>, <strong>6</strong>) in dichloromethane. Here H<small><sub>2</sub></small>L<small><sup>1</sup></small> is valproic acid hydrazone of salicylaldehyde and H<small><sub>2</sub></small>L<small><sup>2</sup></small> is that of 2-hydroxy naphthaldehyde. X-ray crystallographic studies revealed the dual binding mode of the ligands e.g. neutral amido form in dioxoido complex <strong>1</strong> and dianionic iminolato form the oxidomethoxido complex <strong>3</strong>. The redox behaviour of all the complexes were investigated using a combination of experimental and theoretical approaches. Partial reduction of <strong>5</strong>, <strong>6</strong> by constant potential electrolysis (CPE) conforming to a Robin–Day type II mixed-valence species <strong>5a</strong> and <strong>6a</strong> of general formula (L)(O)V<small><sup>IV</sup></small>−O−V<small><sup>V</sup></small>(O)(L). The Complexes catalytically oxidized pyrogallol to purpurogallin and catechol like system to quinone under ambient condition. Catecholase like activity was found to follow a very rare semiquinone radical intermediate for vanadium model system.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"12 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Five new alkyl zinc complexes supported by different formylfluorenimide ligands were prepared and characterized. Complex 1 was obtained by the reaction of 9-[N(CH3)2-Cy-N=CH]Fl (Cy = 2-cyclohexyl) (Fl = Fluorenyl) (L1) with diethylzinc (ZnEt2) in tetrahydrofuran. By reacting 9-[2-pyridyl-CH-N=CH]Fl (L2) with ZnEt2 in tetrahydrofuran to yield complex 2. Under analogous conditions, complexes 3 and 4 were obtained through the reaction of 9-[2-pyridyl-CH(CH3)-N=CH]Fl (L3) and 9-[8-quinoline-CH-N=CH]Fl(L4) with ZnEt2 in tetrahydrofuran, respectively. The above ligands formed a tridentate four-coordinate structure by introduction of THF molecule along with the elimination of one ethyl group during its coordination with zinc. Notably, the formylfluorenimide ligand 9-[2-phenoxy-Ph-N=CH]Fl(Ph = phenyl) (L5) bearing a phenoxy group exhibited unique reactivity compared to the other ligands, which formed a bidentate three-coordinated structure when reacting with ZnEt2 in THF. All complexes were characterized via 1H NMR, 13C NMR spectroscopy, and elemental analysis, with structural determination confirmed through single-crystal X-ray diffraction. Furthermore, the catalytic properties of these complexes were investigated. All these complexes exhibited excellent catalytic activities for hydroboration of benzaldehyde, among which complex 5 demonstrating excellent catalytic performance (up to 99% yield) with a versatile substrates scope and high tolerance to functional groups (27 substrates) at low catalyst loading (0.8 mol%) under mild reaction conditions.
{"title":"Alkylzinc complexes derived from formylfluorenimide ligands: Synthesis, characterization and catalysis for hydroboration of aldehydes and ketones","authors":"Biao Wei, Zhibiao Qin, Hui Miao, Chaoqun Wang, Mengna Huang, Chengxu Liu, Cui-Bing Bai, Zheng Chen","doi":"10.1039/d4dt03395g","DOIUrl":"https://doi.org/10.1039/d4dt03395g","url":null,"abstract":"Five new alkyl zinc complexes supported by different formylfluorenimide ligands were prepared and characterized. Complex 1 was obtained by the reaction of 9-[N(CH3)2-Cy-N=CH]Fl (Cy = 2-cyclohexyl) (Fl = Fluorenyl) (L1) with diethylzinc (ZnEt2) in tetrahydrofuran. By reacting 9-[2-pyridyl-CH-N=CH]Fl (L2) with ZnEt2 in tetrahydrofuran to yield complex 2. Under analogous conditions, complexes 3 and 4 were obtained through the reaction of 9-[2-pyridyl-CH(CH3)-N=CH]Fl (L3) and 9-[8-quinoline-CH-N=CH]Fl(L4) with ZnEt2 in tetrahydrofuran, respectively. The above ligands formed a tridentate four-coordinate structure by introduction of THF molecule along with the elimination of one ethyl group during its coordination with zinc. Notably, the formylfluorenimide ligand 9-[2-phenoxy-Ph-N=CH]Fl(Ph = phenyl) (L5) bearing a phenoxy group exhibited unique reactivity compared to the other ligands, which formed a bidentate three-coordinated structure when reacting with ZnEt2 in THF. All complexes were characterized via 1H NMR, 13C NMR spectroscopy, and elemental analysis, with structural determination confirmed through single-crystal X-ray diffraction. Furthermore, the catalytic properties of these complexes were investigated. All these complexes exhibited excellent catalytic activities for hydroboration of benzaldehyde, among which complex 5 demonstrating excellent catalytic performance (up to 99% yield) with a versatile substrates scope and high tolerance to functional groups (27 substrates) at low catalyst loading (0.8 mol%) under mild reaction conditions.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"92 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paddlewheel-type diruthenium(II,II) complexes are paramagnetic with two unpaired electrons (S = 1) and can be utilized as versatile building blocks for higher-order structures, such as supramolecular complexes, coordination polymers, and metal-organic frameworks, although they are generally highly air-sensitive. In this study, we developed an air-stable paddlewheel-type diruthenium(II,II) complex with two electron-withdrawing 1,8-naphthyridine-2-carboxylate (npc) ligands, [Ru2(μ-npc)2(O2CMe)2] (1). The two acetate ligands in 1 can be replaced by other carboxylate ligands; the solvothermal reactions of 1 with benzoic acid (HO2CPh) yields the heteroleptic [Ru2(μ-npc)2(O2CPh)2] (2), whereas its reaction with 1,8-naphthyridine-2-carboxylic acid (Hnpc) produces the homoleptic [Ru2(μ-npc)2(η2-npc)2] (3). The molecular structures of 1-3 were characterized using paramagnetic 1H NMR, ESI-TOF-MS, elemental analyses, and single-crystal X-ray diffraction, which revealed that 1 and 2 form conventional paddlewheel-type structures, where two npc and two carboxylate ligands coordinate to the Ru2 core in a cis-2:2 arrangement, whereas 3 forms a half-paddlewheel-type structure, with the Ru2 core coordinated by two bridging μ-npc and two chelating η2-npc ligands. Temperature-dependent magnetic susceptibility measurements of 1-3 showed large zero-field splittings (D = 227, 238, and 240 cm-1, respectively) due to the Ru24+ center, and their effective magnetic moments at 300 K, ranging from 2.78 to 2.90 μB, are consistent with the spin-only value of 2.83 μB for an S = 1 system. Electrochemical analyses revealed that 1-3 are redox-active and undergo reversible redox processes; their cyclic voltammetry (CV) diagrams showed an oxidation wave associated with the Ru25+/Ru24+ process and two sequential reduction waves corresponding to the reduction of two npc ligands. Notably, 1-3 show intense broad absorption bands at approximately 500 – 800 nm, theoretically assigned to the metal-ligand charge transfers (MLCTs) from the d(Ru2) to π*(npc) orbitals.
{"title":"Paddlewheel-type and half-paddlewheel-type diruthenium(II,II) complexes with 1,8-naphthyridine-2-carboxylate","authors":"Yusuke Kataoka, Nozomi Tada, Naoki Masamori, Natsumi Yano, Chikako Moriyoshi, Makoto Handa","doi":"10.1039/d4dt03321c","DOIUrl":"https://doi.org/10.1039/d4dt03321c","url":null,"abstract":"Paddlewheel-type diruthenium(II,II) complexes are paramagnetic with two unpaired electrons (S = 1) and can be utilized as versatile building blocks for higher-order structures, such as supramolecular complexes, coordination polymers, and metal-organic frameworks, although they are generally highly air-sensitive. In this study, we developed an air-stable paddlewheel-type diruthenium(II,II) complex with two electron-withdrawing 1,8-naphthyridine-2-carboxylate (npc) ligands, [Ru2(μ-npc)2(O2CMe)2] (1). The two acetate ligands in 1 can be replaced by other carboxylate ligands; the solvothermal reactions of 1 with benzoic acid (HO2CPh) yields the heteroleptic [Ru2(μ-npc)2(O2CPh)2] (2), whereas its reaction with 1,8-naphthyridine-2-carboxylic acid (Hnpc) produces the homoleptic [Ru2(μ-npc)2(η2-npc)2] (3). The molecular structures of 1-3 were characterized using paramagnetic 1H NMR, ESI-TOF-MS, elemental analyses, and single-crystal X-ray diffraction, which revealed that 1 and 2 form conventional paddlewheel-type structures, where two npc and two carboxylate ligands coordinate to the Ru2 core in a cis-2:2 arrangement, whereas 3 forms a half-paddlewheel-type structure, with the Ru2 core coordinated by two bridging μ-npc and two chelating η2-npc ligands. Temperature-dependent magnetic susceptibility measurements of 1-3 showed large zero-field splittings (D = 227, 238, and 240 cm-1, respectively) due to the Ru24+ center, and their effective magnetic moments at 300 K, ranging from 2.78 to 2.90 μB, are consistent with the spin-only value of 2.83 μB for an S = 1 system. Electrochemical analyses revealed that 1-3 are redox-active and undergo reversible redox processes; their cyclic voltammetry (CV) diagrams showed an oxidation wave associated with the Ru25+/Ru24+ process and two sequential reduction waves corresponding to the reduction of two npc ligands. Notably, 1-3 show intense broad absorption bands at approximately 500 – 800 nm, theoretically assigned to the metal-ligand charge transfers (MLCTs) from the d(Ru2) to π*(npc) orbitals.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"17 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ying Zheng, Zhiyou Wang, Qianju Song, Zao Yi, Shubo Cheng, You-Gen Yi
Mid infrared thermal radiation has attracted attention due to its wide range of applications. Compared to the static process of thermal emission, the dynamic control of it is more suitable for practical applications. Based on phase change materials, this article designs a controllable thermal emitter. When the temperature changes from low to high, VO2 transitions from a dielectric state to a metallic state, and its imaginary part of dielectric constant significantly increases, leading to differences in emission characteristics. At low temperatures, the device is in a low dielectric state and has weak resonance with incident light. The main emission comes from the bottom of the grating structure, with an emissivity of 0.21. At high temperatures, the structure is in a high dielectric state, and multiple resonance modes are excited within the structure, such as cavity resonance and surface plasmon resonance, which increases the emissivity to 0.95 and achieves effective heat dissipation. To sum up, by utilizing the phase change material VO2, this structure possesses thermal management capability and thermal stability, and has broad application prospects.
{"title":"Thermal management broadband emitting device based on VO2 applied in the mid infrared band","authors":"Ying Zheng, Zhiyou Wang, Qianju Song, Zao Yi, Shubo Cheng, You-Gen Yi","doi":"10.1039/d4dt03422h","DOIUrl":"https://doi.org/10.1039/d4dt03422h","url":null,"abstract":"Mid infrared thermal radiation has attracted attention due to its wide range of applications. Compared to the static process of thermal emission, the dynamic control of it is more suitable for practical applications. Based on phase change materials, this article designs a controllable thermal emitter. When the temperature changes from low to high, VO2 transitions from a dielectric state to a metallic state, and its imaginary part of dielectric constant significantly increases, leading to differences in emission characteristics. At low temperatures, the device is in a low dielectric state and has weak resonance with incident light. The main emission comes from the bottom of the grating structure, with an emissivity of 0.21. At high temperatures, the structure is in a high dielectric state, and multiple resonance modes are excited within the structure, such as cavity resonance and surface plasmon resonance, which increases the emissivity to 0.95 and achieves effective heat dissipation. To sum up, by utilizing the phase change material VO2, this structure possesses thermal management capability and thermal stability, and has broad application prospects.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"74 6 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The physical separation of C2H2 from CO2 on metal–organic frameworks (MOFs) has received a substantial amount of research interest due to its advantages of simplicity, security, and energy efficiency. However, the exploitation of ideal MOF adsorbents for C2H2/CO2 separation remains a challenging task due to their similar physical properties and molecular sizes. Herein, we report a unique C2H2 nano-trap constructed using accessible oxygen and nitrogen sites, which exhibits energetic favorability toward C2H2 molecules. This material exhibits a good acetylene capacity of 55.31 cm3 g−1 and high C2H2/CO2 selectivity of 7.0 under ambient conditions. We have combined in situ IR spectroscopy and in-depth theoretical calculations to unravel the synergistic interactions driven by the high density of accessible oxygen and nitrogen sites. Furthermore, dynamic breakthrough experiments confirmed the capability of TUTJ-201Ni for the separation of binary C2H2/CO2 mixtures. This study on Ni-based MOFs will enrich Lewis basic site rich MOFs for gas adsorption and separation applications.
{"title":"A Lewis basic site rich metal–organic framework featuring a hydrogen-bonded acetylene nano-trap for the efficient separation of C2H2/CO2","authors":"Mengyue Lu, Zhiwei Zhao, Yuhao Tang, Yating Wang, Feifei Zhang, Jinping Li, Jiangfeng Yang","doi":"10.1039/d4dt03411b","DOIUrl":"https://doi.org/10.1039/d4dt03411b","url":null,"abstract":"The physical separation of C<small><sub>2</sub></small>H<small><sub>2</sub></small> from CO<small><sub>2</sub></small> on metal–organic frameworks (MOFs) has received a substantial amount of research interest due to its advantages of simplicity, security, and energy efficiency. However, the exploitation of ideal MOF adsorbents for C<small><sub>2</sub></small>H<small><sub>2</sub></small>/CO<small><sub>2</sub></small> separation remains a challenging task due to their similar physical properties and molecular sizes. Herein, we report a unique C<small><sub>2</sub></small>H<small><sub>2</sub></small> nano-trap constructed using accessible oxygen and nitrogen sites, which exhibits energetic favorability toward C<small><sub>2</sub></small>H<small><sub>2</sub></small> molecules. This material exhibits a good acetylene capacity of 55.31 cm<small><sup>3</sup></small> g<small><sup>−1</sup></small> and high C<small><sub>2</sub></small>H<small><sub>2</sub></small>/CO<small><sub>2</sub></small> selectivity of 7.0 under ambient conditions. We have combined <em>in situ</em> IR spectroscopy and in-depth theoretical calculations to unravel the synergistic interactions driven by the high density of accessible oxygen and nitrogen sites. Furthermore, dynamic breakthrough experiments confirmed the capability of TUTJ-201Ni for the separation of binary C<small><sub>2</sub></small>H<small><sub>2</sub></small>/CO<small><sub>2</sub></small> mixtures. This study on Ni-based MOFs will enrich Lewis basic site rich MOFs for gas adsorption and separation applications.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"28 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three new sodium manganese fluoro-pyrophosphate compounds, namely, Na5.5Mn1.5(P2O7)2F0.5 (I), Na7Mn0.75(P2O7)2F2 (II), and Na9Mn3(P2O7)4F (III), have been synthesized by heating a mixture of NaPF6, Na2PO3F or NaH2PO4 with different Mn sources in NaNO3 and KNO3 fluxes. The structures of the title compounds were characterized via single-crystal X-ray diffraction (XRD). II is characteristic of a shell of Na+ ions that encloses one [Mn0.75(P2O7)2F2]7− unit, whereas I and III reveal three-dimensional (3D) frameworks that consist of MnO6, Mn/NaO5F0.5 octahedra or MnO6 octahedra and distorted MnO5 square pyramids with P2O7 units, where Na+ cations reside in different-membered ring one-dimensional (1D) tunnels. The estimated total Na+ ion conductivity for a pellet of III in open air is 10−5 S cm−1 at 400 °C, which is lower than that of many NASICON-type compounds at room temperature, with a higher activation energy of 0.89 eV for III compared to the value of ∼0.4 eV for high-performance sodium ion conductors. The analysis of Na+ diffusion pathways revealed that percolation occurs through a zig-zag chain along the b axis via the bond valence energy landscape approach. Detailed characterization, such as spectroscopic and magnetic properties and specific heat for III, is also reported.
通过在 NaNO3 和 KNO3 通量下加热 NaPF6、Na2PO3F 或 NaH2PO4 与不同锰源的混合物，合成了三种新的氟焦磷酸钠锰化合物，即 Na5.5Mn1.5(P2O7)2F0.5 (I)、Na7Mn0.75(P2O7)2F2 (II) 和 Na9Mn3(P2O7)4F (III)。通过单晶 X 射线衍射 (XRD) 对标题化合物的结构进行了表征。其中，Ⅰ和Ⅲ揭示了由 MnO6、Mn/NaO5F0.5 八面体或 MnO6 八面体以及带有 P2O7 单元的变形 MnO5 正方体金字塔组成的三维（3D）框架，Na+阳离子位于不同元环的一维（1D）隧道中。与高性能钠离子导体的活化能 0.4 eV 相比，III 的活化能更高，为 0.89 eV。对 Na+ 扩散路径的分析表明，通过键价能谱方法，渗流是通过沿 b 轴的之字形链发生的。此外，还报告了详细的特性分析，如光谱和磁性能以及 III 的比热。
{"title":"Open frameworks in the NaxMny(P2O7)mFn fluoro-pyrophosphates system","authors":"Feifan Li, Yaping Li, Victor Duffort, Olivier Mentré, Claire Minaud, Qingqing Huang, Xiedong Cheng, Rui Cui, Minfeng Lü","doi":"10.1039/d4dt03027c","DOIUrl":"https://doi.org/10.1039/d4dt03027c","url":null,"abstract":"Three new sodium manganese fluoro-pyrophosphate compounds, namely, Na<small><sub>5.5</sub></small>Mn<small><sub>1.5</sub></small>(P<small><sub>2</sub></small>O<small><sub>7</sub></small>)<small><sub>2</sub></small>F<small><sub>0.5</sub></small> (<strong>I</strong>), Na<small><sub>7</sub></small>Mn<small><sub>0.75</sub></small>(P<small><sub>2</sub></small>O<small><sub>7</sub></small>)<small><sub>2</sub></small>F<small><sub>2</sub></small> (<strong>II</strong>), and Na<small><sub>9</sub></small>Mn<small><sub>3</sub></small>(P<small><sub>2</sub></small>O<small><sub>7</sub></small>)<small><sub>4</sub></small>F (<strong>III</strong>), have been synthesized by heating a mixture of NaPF<small><sub>6</sub></small>, Na<small><sub>2</sub></small>PO<small><sub>3</sub></small>F or NaH<small><sub>2</sub></small>PO<small><sub>4</sub></small> with different Mn sources in NaNO<small><sub>3</sub></small> and KNO<small><sub>3</sub></small> fluxes. The structures of the title compounds were characterized <em>via</em> single-crystal X-ray diffraction (XRD). <strong>II</strong> is characteristic of a shell of Na<small><sup>+</sup></small> ions that encloses one [Mn<small><sub>0.75</sub></small>(P<small><sub>2</sub></small>O<small><sub>7</sub></small>)<small><sub>2</sub></small>F<small><sub>2</sub></small>]<small><sup>7−</sup></small> unit, whereas <strong>I</strong> and <strong>III</strong> reveal three-dimensional (3D) frameworks that consist of MnO<small><sub>6</sub></small>, Mn/NaO<small><sub>5</sub></small>F<small><sub>0.5</sub></small> octahedra or MnO<small><sub>6</sub></small> octahedra and distorted MnO<small><sub>5</sub></small> square pyramids with P<small><sub>2</sub></small>O<small><sub>7</sub></small> units, where Na<small><sup>+</sup></small> cations reside in different-membered ring one-dimensional (1D) tunnels. The estimated total Na<small><sup>+</sup></small> ion conductivity for a pellet of <strong>III</strong> in open air is 10<small><sup>−5</sup></small> S cm<small><sup>−1</sup></small> at 400 °C, which is lower than that of many NASICON-type compounds at room temperature, with a higher activation energy of 0.89 eV for <strong>III</strong> compared to the value of ∼0.4 eV for high-performance sodium ion conductors. The analysis of Na<small><sup>+</sup></small> diffusion pathways revealed that percolation occurs through a zig-zag chain along the <em>b</em> axis <em>via</em> the bond valence energy landscape approach. Detailed characterization, such as spectroscopic and magnetic properties and specific heat for <strong>III</strong>, is also reported.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this Frontier Article, the work carried out within our research group in Bologna in the field of surface decorated metal carbonyl clusters will be outlined and put in a more general context. After a short Introduction, clusters composed of a metal carbonyl core decorated on the surface by metal-ligand fragments will be analyzed. Both metal-ligand fragments behaving as Lewis acids and Lewis bases will be considered. Then, the focus will be moved to clusters composed of a naked metal core decorated and stabilized on the surface by metal-carbonyl fragments. The structure and bonding (where theoretical studies are available) of such surface decorated metal carbonyl clusters will be presented, and compared to atomically precise ligated nanoclusters.
{"title":"Surface decorated metal carbonyl clusters: bridging organometallic molecular clusters and atomically precise ligated nanoclusters","authors":"Cristiana Cesari, Cristina Femoni, Francesca Forti, Maria Carmela Iapalucci, Giorgia Scorzoni, Stefano Zacchini","doi":"10.1039/d4dt03266g","DOIUrl":"https://doi.org/10.1039/d4dt03266g","url":null,"abstract":"In this Frontier Article, the work carried out within our research group in Bologna in the field of surface decorated metal carbonyl clusters will be outlined and put in a more general context. After a short Introduction, clusters composed of a metal carbonyl core decorated on the surface by metal-ligand fragments will be analyzed. Both metal-ligand fragments behaving as Lewis acids and Lewis bases will be considered. Then, the focus will be moved to clusters composed of a naked metal core decorated and stabilized on the surface by metal-carbonyl fragments. The structure and bonding (where theoretical studies are available) of such surface decorated metal carbonyl clusters will be presented, and compared to atomically precise ligated nanoclusters.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"21 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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