Pietro Mariani, Jacopo Orsilli, Henk Stoffel, Simone Mascotto, Damiano Monticelli, Enrico Berretti, Alessandro Lavacchi, Luca Bignardi, Cinzia Cepek, Maria Goula, Nikolaos Charisiou, Angeliki Latsiou, Silvia Mostoni, Barbara Di Credico, Roberto Scotti, Massimiliano D'Arienzo
In this work, we examine the redox behavior and exsolution kinetics of Ni and Fe in A-site-deficient Sr 0.95 Ti 1-x+y Fe x Ni y O 3±δ , combining TPR, XAS, electron microscopy and EPR to elucidate dopant-specific contributions to defect chemistry and metal nucleation. In particular, TPR data indicated that Fe predominantly governs the formation and reducibility of oxygen-vacancy-associated defects, generating reduced Fe species at comparatively low temperature, whereas Ni dictates the overall reduction extent. In fact, as assessed by XAS, Ni-only samples exhibit relatively low conversion to Ni (0), while co-doping with Fe boosts Ni exsolution. Moreover, it turned out that even a tiny Ni amount promotes iron reduction, as unveiled by EXAFS spectra. Along this line, STEM analyses confirmed the surface segregation of well-anchored Fe-Ni co-exsolved nanoparticles for co-doped perovskites, while scarce exsolution was observed for Fe-doped samples. EPR completed the picture corroborating that Fe species, incorporated in the perovskite as highly stable Fe(III) substitutional defects, are less reducible and less mobile than Ni ones, which instead appear mostly as intercalated sites. Such Fe defects become mobile and undergo surface segregation only when Ni is incorporated in the lattice. These structure-property relationships directly translate into enhanced performance in the RWGS reaction of co-doped perovskites, where Fe drives vacancy-mediated redox processes while Ni promotes H₂ dissociation. Overall, the results indicate that the methodological approach developed here can be extended to other exsolvable dopants (e.g., Co), offering a pathway toward the rational design of exsolved catalysts with tunable structures and compositions for advanced energy-conversion applications.
在这项工作中，我们研究了Ni和Fe在a位缺陷Sr 0.95 Ti 1-x+y Fe x Ni y O 3±δ中的氧化还原行为和析出动力学，结合TPR， XAS，电子显微镜和EPR来阐明掺杂剂对缺陷化学和金属成核的特异性贡献。特别是，TPR数据表明，Fe主要控制了氧空位相关缺陷的形成和还原性，在相对较低的温度下产生了还原铁，而Ni则决定了整体的还原程度。事实上，通过XAS评估，纯Ni样品向Ni(0)的转化相对较低，而与Fe共掺杂则促进了Ni的析出。此外，正如EXAFS光谱所揭示的那样，即使是微量的Ni也会促进铁的还原。沿着这条线，STEM分析证实了共掺杂钙钛矿的铁-镍共溶纳米颗粒的表面偏析，而铁掺杂样品的表面偏析很少。EPR完成了这幅图，证实了作为高度稳定的Fe（III）取代缺陷结合在钙钛矿中的Fe物种比Ni物种更不容易被还原和迁移，而Ni则主要作为插入位点出现。只有在晶格中加入Ni时，这些Fe缺陷才会移动并发生表面偏析。这些结构-性能关系直接转化为共掺杂钙钛矿在RWGS反应中的性能增强，其中Fe驱动空位介导的氧化还原过程，而Ni促进H₂解离。总的来说，结果表明，这里开发的方法方法可以扩展到其他可溶掺杂剂（例如Co），为合理设计具有可调结构和成分的可溶催化剂提供了一条途径，用于先进的能量转换应用。
{"title":"Bimetallic Fe-Ni exsolution from A site deficient SrTiO3: insight into the reciprocal role of metal active centers","authors":"Pietro Mariani, Jacopo Orsilli, Henk Stoffel, Simone Mascotto, Damiano Monticelli, Enrico Berretti, Alessandro Lavacchi, Luca Bignardi, Cinzia Cepek, Maria Goula, Nikolaos Charisiou, Angeliki Latsiou, Silvia Mostoni, Barbara Di Credico, Roberto Scotti, Massimiliano D'Arienzo","doi":"10.1039/d5qi02469b","DOIUrl":"https://doi.org/10.1039/d5qi02469b","url":null,"abstract":"In this work, we examine the redox behavior and exsolution kinetics of Ni and Fe in A-site-deficient Sr 0.95 Ti 1-x+y Fe x Ni y O 3±δ , combining TPR, XAS, electron microscopy and EPR to elucidate dopant-specific contributions to defect chemistry and metal nucleation. In particular, TPR data indicated that Fe predominantly governs the formation and reducibility of oxygen-vacancy-associated defects, generating reduced Fe species at comparatively low temperature, whereas Ni dictates the overall reduction extent. In fact, as assessed by XAS, Ni-only samples exhibit relatively low conversion to Ni (0), while co-doping with Fe boosts Ni exsolution. Moreover, it turned out that even a tiny Ni amount promotes iron reduction, as unveiled by EXAFS spectra. Along this line, STEM analyses confirmed the surface segregation of well-anchored Fe-Ni co-exsolved nanoparticles for co-doped perovskites, while scarce exsolution was observed for Fe-doped samples. EPR completed the picture corroborating that Fe species, incorporated in the perovskite as highly stable Fe(III) substitutional defects, are less reducible and less mobile than Ni ones, which instead appear mostly as intercalated sites. Such Fe defects become mobile and undergo surface segregation only when Ni is incorporated in the lattice. These structure-property relationships directly translate into enhanced performance in the RWGS reaction of co-doped perovskites, where Fe drives vacancy-mediated redox processes while Ni promotes H₂ dissociation. Overall, the results indicate that the methodological approach developed here can be extended to other exsolvable dopants (e.g., Co), offering a pathway toward the rational design of exsolved catalysts with tunable structures and compositions for advanced energy-conversion applications.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"280 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rational design of high-performance visible-light-responsive and recyclable C-H bond activation photocatalysts represents one of the critical challenges for advancing sustainable photocatalytic chemistry. Here, we successfully obtained a novel crystalline material (CR-DT) through the self-assembly of decatungstate (DT) with Ru metalloligands, which represents the first example of the crystalline polyoxometalate@metal-organic frameworks incorporating DT with photosensitive metalloligands. CR-DT not only retains the HAT function of DT but also overcomes its limitations of effectiveness only in the ultraviolet light region and difficulty in reuse, further enhancing photocatalytic performance. When CR-DT was employed as the photocatalyst for the Baeyer-Villiger oxidation reaction, the catalytic generation of εcaprolactone was achieved in yields up to 99.5%, with TON and TOF of 995 and 678 h -1 , respectively, both of which were the highest among the photocatalysts currently used for this reaction. Remarkably, CR-DT exhibited excellent recyclability, maintained high yield even after ten cycles, providing a viable candidate for industrial applications. Recently, metal-organic frameworks (MOFs) have emerged as a distinctive class of materials with well-defined structures, large porosity, and customizable functions, which have established MOFs as a versatile platform for directional construction of high-performance photocatalysts through precise spatial organization of active sites. [23][24][25][26] Choosing a suitable secondary building unit serves as an essential strategy for achieving precise functional customization of MOFs. 27,28 The DT module with HAT
合理设计高性能可见光响应和可回收的C-H键活化光催化剂是推进可持续光催化化学的关键挑战之一。在这里，我们成功地通过十钨酸盐（DT）与Ru金属配体的自组装获得了一种新的晶体材料（CR-DT），这是将DT与光敏金属配体结合在一起的晶体polyoxometalate@metal-organic框架的第一个例子。CR-DT既保留了DT的HAT功能，又克服了其仅在紫外光区有效和难以重复使用的局限性，进一步提高了光催化性能。采用CR-DT作为Baeyer-Villiger氧化反应的光催化剂，催化生成ε己内酯的产率高达99.5%，TON和TOF分别为995和678 h -1，是目前用于该反应的光催化剂中最高的。值得注意的是，CR-DT表现出优异的可回收性，即使在10次循环后仍保持高收率，为工业应用提供了可行的候选材料。近年来，金属有机框架（mof）作为一种具有明确结构、大孔隙率和可定制功能的独特材料而出现，这使得mof成为通过精确的活性位点空间组织定向构建高性能光催化剂的通用平台。选择合适的二次建筑单元是实现mof精确功能定制的基本策略。27,28带有HAT的DT模块
{"title":"Upgraded Decatungstate: The Visible-Light-Responsive, Recyclable, and Efficient Photocatalyst Achieved via Self-Assembly","authors":"Yanan Liu, Luoning Li, Minzhen Cai, Jingping Wang, Jing Wang, Pengtao Ma, Jingyang Niu","doi":"10.1039/d5qi02558c","DOIUrl":"https://doi.org/10.1039/d5qi02558c","url":null,"abstract":"The rational design of high-performance visible-light-responsive and recyclable C-H bond activation photocatalysts represents one of the critical challenges for advancing sustainable photocatalytic chemistry. Here, we successfully obtained a novel crystalline material (CR-DT) through the self-assembly of decatungstate (DT) with Ru metalloligands, which represents the first example of the crystalline polyoxometalate@metal-organic frameworks incorporating DT with photosensitive metalloligands. CR-DT not only retains the HAT function of DT but also overcomes its limitations of effectiveness only in the ultraviolet light region and difficulty in reuse, further enhancing photocatalytic performance. When CR-DT was employed as the photocatalyst for the Baeyer-Villiger oxidation reaction, the catalytic generation of εcaprolactone was achieved in yields up to 99.5%, with TON and TOF of 995 and 678 h -1 , respectively, both of which were the highest among the photocatalysts currently used for this reaction. Remarkably, CR-DT exhibited excellent recyclability, maintained high yield even after ten cycles, providing a viable candidate for industrial applications. Recently, metal-organic frameworks (MOFs) have emerged as a distinctive class of materials with well-defined structures, large porosity, and customizable functions, which have established MOFs as a versatile platform for directional construction of high-performance photocatalysts through precise spatial organization of active sites. [23][24][25][26] Choosing a suitable secondary building unit serves as an essential strategy for achieving precise functional customization of MOFs. 27,28 The DT module with HAT","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"96 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deyue Cao, Bowen Zheng, Ningjie Xu, Xin Wang, Gen Luo
Although rare-earth-catalysed C-H addition to unsaturated hydrocarbons has emerged as a powerful and atom-economical strategy, the mechanistic principles governing selectivity in reactions involving conjugated dienes remain poorly understood. Here, density functional theory (DFT) calculations are employed to elucidate the mechanistic origins of divergent selectivity in rare-earth-catalysed pyridine C-H alkylation and aldimine annulation reactions with conjugated dienes. The results indicate that, despite producing formal 1,4-and 1,2-insertion products, respectively, both transformations proceed through a preferred 1,4-cis-insertion pathway to generate η3 -allyl intermediates. Comprehensive computational analyses reveal that the divergence arises from distinct post-insertion pathways: sterically favored protonation at the terminal carbon in pyridine alkylation, versus electronically and sterically driven cyclization at the internal carbon in aldimine annulation. These results demonstrate that product selectivity is dictated primarily by the site-selective evolution of the η3 -allyl intermediate rather than by the initial insertion event. This work establishes a unified mechanistic framework for diene-enabled rare-earthcatalysed C-H functionalization and provides theoretical insights into selectivity control through post-insertion reactivity.
{"title":"Insertion Modes and Origins of Product Selectivity in Rare-Earth-Catalysed C-H Functionalization with Conjugated Dienes","authors":"Deyue Cao, Bowen Zheng, Ningjie Xu, Xin Wang, Gen Luo","doi":"10.1039/d6qi00049e","DOIUrl":"https://doi.org/10.1039/d6qi00049e","url":null,"abstract":"Although rare-earth-catalysed C-H addition to unsaturated hydrocarbons has emerged as a powerful and atom-economical strategy, the mechanistic principles governing selectivity in reactions involving conjugated dienes remain poorly understood. Here, density functional theory (DFT) calculations are employed to elucidate the mechanistic origins of divergent selectivity in rare-earth-catalysed pyridine C-H alkylation and aldimine annulation reactions with conjugated dienes. The results indicate that, despite producing formal 1,4-and 1,2-insertion products, respectively, both transformations proceed through a preferred 1,4-cis-insertion pathway to generate η3 -allyl intermediates. Comprehensive computational analyses reveal that the divergence arises from distinct post-insertion pathways: sterically favored protonation at the terminal carbon in pyridine alkylation, versus electronically and sterically driven cyclization at the internal carbon in aldimine annulation. These results demonstrate that product selectivity is dictated primarily by the site-selective evolution of the η3 -allyl intermediate rather than by the initial insertion event. This work establishes a unified mechanistic framework for diene-enabled rare-earthcatalysed C-H functionalization and provides theoretical insights into selectivity control through post-insertion reactivity.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"236 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tatyana S. Koptseva, Evgeny V. Baranov, Sergey Yu. Ketkov, Igor L. Fedushkin
The reaction of aluminum hydride [(ArBIG-bian)AlH2]−[Li(THF)4]+ (1) (ArBIG-bian = dianion of 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene) with TM(CO)6 yields σ-complexes [(ArBIG-bian)Al(μ2-H)2TM(CO)4]−[Li(Solv)3]+ (TM = Cr, 2; Mo, 3; W, 4), in which two hydride ligands symmetrically bridge the Al and TM centers. Molybdenum hydride [(ArBIG-bian)Al(μ2-H)2Mo(CO)4Li(THF)3] 3b reacts with ammonia through H2 elimination to form an amido-bridged derivative [(ArBIG-bian)Al(μ2-NH2)2Mo(CO)4]−[Li(THF)4]+ (5). In contrast, the reactions of hydride 1 with Cp2Ni and Cp3Er (Cp = C5H5) afford a unique Ni(II)(μ2-H)2Al(III) complex [(ArBIG-bian)(THF)Al(μ2-H)2NiCp] (6) and dihydride [(ArBIG-bian)Al(μ2-H)2Er(Cp)2THF] (7), respectively. The latter represents the first crystallographically characterized Er/Al complex. Products 2–7 have been identified via IR and NMR spectroscopy, and their molecular structures were determined via single-crystal X-ray analysis. The electronic structures of 2, 3 and 6 were examined via DFT calculations, which revealed direct Al–TM bonding.
{"title":"Plural bonding interactions in Al(μ2-H)2TM species","authors":"Tatyana S. Koptseva, Evgeny V. Baranov, Sergey Yu. Ketkov, Igor L. Fedushkin","doi":"10.1039/d5qi02383a","DOIUrl":"https://doi.org/10.1039/d5qi02383a","url":null,"abstract":"The reaction of aluminum hydride [(Ar<small><sup>BIG</sup></small>-bian)AlH<small><sub>2</sub></small>]<small><sup>−</sup></small>[Li(THF)<small><sub>4</sub></small>]<small><sup>+</sup></small> (<strong>1</strong>) (Ar<small><sup>BIG</sup></small>-bian = dianion of 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene) with TM(CO)<small><sub>6</sub></small> yields σ-complexes [(Ar<small><sup>BIG</sup></small>-bian)Al(μ<small><sup>2</sup></small>-H)<small><sub>2</sub></small>TM(CO)<small><sub>4</sub></small>]<small><sup>−</sup></small>[Li(Solv)<small><sub>3</sub></small>]<small><sup>+</sup></small> (TM = Cr, <strong>2</strong>; Mo, <strong>3</strong>; W, <strong>4</strong>), in which two hydride ligands symmetrically bridge the Al and TM centers. Molybdenum hydride [(Ar<small><sup>BIG</sup></small>-bian)Al(μ<small><sup>2</sup></small>-H)<small><sub>2</sub></small>Mo(CO)<small><sub>4</sub></small>Li(THF)<small><sub>3</sub></small>] <strong>3b</strong> reacts with ammonia through H<small><sub>2</sub></small> elimination to form an amido-bridged derivative [(Ar<small><sup>BIG</sup></small>-bian)Al(μ<small><sup>2</sup></small>-NH<small><sub>2</sub></small>)<small><sub>2</sub></small>Mo(CO)<small><sub>4</sub></small>]<small><sup>−</sup></small>[Li(THF)<small><sub>4</sub></small>]<small><sup>+</sup></small> (<strong>5</strong>). In contrast, the reactions of hydride <strong>1</strong> with Cp<small><sub>2</sub></small>Ni and Cp<small><sub>3</sub></small>Er (Cp = C<small><sub>5</sub></small>H<small><sub>5</sub></small>) afford a unique Ni(<small>II</small>)(μ<small><sup>2</sup></small>-H)<small><sub>2</sub></small>Al(<small>III</small>) complex [(Ar<small><sup>BIG</sup></small>-bian)(THF)Al(μ<small><sup>2</sup></small>-H)<small><sub>2</sub></small>NiCp] (<strong>6</strong>) and dihydride [(Ar<small><sup>BIG</sup></small>-bian)Al(μ<small><sup>2</sup></small>-H)<small><sub>2</sub></small>Er(Cp)<small><sub>2</sub></small>THF] (<strong>7</strong>), respectively. The latter represents the first crystallographically characterized Er/Al complex. Products <strong>2–7</strong> have been identified <em>via</em> IR and NMR spectroscopy, and their molecular structures were determined <em>via</em> single-crystal X-ray analysis. The electronic structures of <strong>2</strong>, <strong>3</strong> and <strong>6</strong> were examined <em>via</em> DFT calculations, which revealed direct Al–TM bonding.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"41 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laura Cuevas, María Mar Quesada-Moreno, Estibaliz Ruiz-Bilbao, Juan Manuel Gutierrez-Zorrilla, Jurek Krzystek, Mykhaylo Ozerov, Juan Ramón Jiménez, Enrique Colacio
This work reports on a mononuclear trigonal prismatic complex [CoIIL](ClO4)2 (1) and a trinuclear linear phenoxido-bridged complex [(CoIIL1)2CoII] (2), where L and H3L1 are N6 and N3O3 tripodal ligands derived from the respective condensation of the cis, cis-1,3,5-tiaminocyclohexane with either 1-methylimidazol-2-carbaldehyde or salicylaldehyde. These compounds have been studied by X-ray single-crystal diffraction, dc and ac magnetism, High-Frequency and -Field Electron Paramagnetic Resonance spectroscopy (HFEPR), Far Infrared Magnetic Spectroscopy (FIRMS) and quantum chemical calculations. The results obtained for 1 show that N₆-tripodal Schiff-base ligands incorporating 1-methylimidazole donors yield trigonal-prismatic mononuclear complexes that typically display C₃ symmetry and exhibit very large, purely easy-axis magnetic anisotropy. In fact, complex 1 exhibits an energy gap between the ground and the first excited state (2D) of 228 cm-1 (directly measured by FIRMS), that can be considered as the maximum limit for the easy magnetic anisotropy in this type of complexes. The symmetry-driven large 2D value, together with the parallel alignment of the anisotropy axes, reduces QTM (Quantum Tunnelling of Magnetization) and yields mononuclear single-molecule magnet (MSMM) behaviour, with the observation of magnetic relaxation through a Raman process and open hysteresis at zero field. In compound 2, the combination of the strong easy-axis anisotropy of the local CoII ions, collinearity of the local anisotropy axes and sizable intramolecular magnetic exchange interactions between the CoII ions in triple phenoxido-bridged linear trinuclear complexes causes the full quenching to the QTM and the observation of SMM behaviour with open hysteresis at zero field. Theoretical calculations point out that the magnetic interaction between the ground Kramers doublets (KDs) of the local CoII ions generates four KDs and the magnetic relaxation occurs through the first excited KD via an Orbach process. Supporting this suggestion, the experimental value for the effective thermal energy barrier extracted from FIRMS of 76.8 cm-1is not too far from the theoretical calculated value of 59.54 cm-1.
{"title":"Symmetry control and magnetic exchange coupling in SMMs based on Co(II) complexes","authors":"Laura Cuevas, María Mar Quesada-Moreno, Estibaliz Ruiz-Bilbao, Juan Manuel Gutierrez-Zorrilla, Jurek Krzystek, Mykhaylo Ozerov, Juan Ramón Jiménez, Enrique Colacio","doi":"10.1039/d5qi02196k","DOIUrl":"https://doi.org/10.1039/d5qi02196k","url":null,"abstract":"This work reports on a mononuclear trigonal prismatic complex [CoIIL](ClO4)2 (1) and a trinuclear linear phenoxido-bridged complex [(CoIIL1)2CoII] (2), where L and H3L1 are N6 and N3O3 tripodal ligands derived from the respective condensation of the cis, cis-1,3,5-tiaminocyclohexane with either 1-methylimidazol-2-carbaldehyde or salicylaldehyde. These compounds have been studied by X-ray single-crystal diffraction, dc and ac magnetism, High-Frequency and -Field Electron Paramagnetic Resonance spectroscopy (HFEPR), Far Infrared Magnetic Spectroscopy (FIRMS) and quantum chemical calculations. The results obtained for 1 show that N₆-tripodal Schiff-base ligands incorporating 1-methylimidazole donors yield trigonal-prismatic mononuclear complexes that typically display C₃ symmetry and exhibit very large, purely easy-axis magnetic anisotropy. In fact, complex 1 exhibits an energy gap between the ground and the first excited state (2D) of 228 cm-1 (directly measured by FIRMS), that can be considered as the maximum limit for the easy magnetic anisotropy in this type of complexes. The symmetry-driven large 2D value, together with the parallel alignment of the anisotropy axes, reduces QTM (Quantum Tunnelling of Magnetization) and yields mononuclear single-molecule magnet (MSMM) behaviour, with the observation of magnetic relaxation through a Raman process and open hysteresis at zero field. In compound 2, the combination of the strong easy-axis anisotropy of the local CoII ions, collinearity of the local anisotropy axes and sizable intramolecular magnetic exchange interactions between the CoII ions in triple phenoxido-bridged linear trinuclear complexes causes the full quenching to the QTM and the observation of SMM behaviour with open hysteresis at zero field. Theoretical calculations point out that the magnetic interaction between the ground Kramers doublets (KDs) of the local CoII ions generates four KDs and the magnetic relaxation occurs through the first excited KD via an Orbach process. Supporting this suggestion, the experimental value for the effective thermal energy barrier extracted from FIRMS of 76.8 cm-1is not too far from the theoretical calculated value of 59.54 cm-1.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"89 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria-Gabriela Alexandru, Diana Visinescu, Sergiu Shova, Fernando Nicolás Moliner, Mario Pacheco, Francesc Lloret
An isostructural series of neutral cyano-bridged tetranuclear iron(III)-lanthanide(III) complexes of general formula {[Fe(htpzb)(CN)(μ-CN)2]2[Ln(dmbpy)(NO3)2(H2O)]2}·2CH3CN·2H2O [Ln = Gd (1), Tb (2), Dy (3), Ho (4), and Er (5); htpzb = hydrotris(pyrazolyl)borate and dmbpy = 4,4’-dimethyl-2,2’-bipyridine] was synthesized and structurally and magnetically characterized. Single-crystal X-ray analysis of 1-5 revealed the formation of neutral cyano-bridged {FeIII2LnIII2} complexes (Ln = Gd, Tb, Dy, Ho, and Er) of square-like topology that crystallize in the triclinic P-1 space group. Solid-state direct-current magnetic susceptibility analysis evidenced weak intramolecular antiferromagnetic FeIII-LnIII interactions in 1 (Ln = Gd) together with large local magnetic anisotropies from the LnIII ion in 2-5 (Ln = Tb, Dy, Ho, and Er). Frequency-dependent alternating current magnetic susceptibility signals occurred for 1-5 under an applied dc magnetic field of H = 1.0 (1) or 0.5 T (2-5), indicating field-induced slow magnetic relaxation effects typical of single-molecule magnets. Depending on the non-Kramer (Tb, Ho) or Kramer (Gd, Dy, Er) nature of the LnIII ion, a single magnetic relaxation process via Orbach or Raman mechanism (2 and 4) or a multiple magnetic relaxation process that combines Orbach or Raman plus quantum tunneling of magnetization and/or direct (1, 3, and 5) mechanisms occurred along this series. 1-5 showed large magnetocaloric effects with a high to moderate maximum value of the magnetic entropy change at optimum working temperatures just above He liquefaction [-ΔSmax = 16.51 (1), 5.42 (2), 6.02 (3), 4.56 (4), and 5.86 J kg-1 K-1 (5) for H = 5 T at Topt = Tmax = 2 (1), 4 (2, 3 and 5), and 6 K (4)], as well as a high to moderate magnetocaloric index at rather low optimum working fields [MCI = 6.4 (1), 3.3 (2), 4.7 (3), 0.9 (4), and 3.6 J kg−1 K−1 T−1 (5) for Hopt = Hmax = 1.0 (1), 0.6 (2), 0.4 (3), 0.8 (4), and 0.6 T (5) at T = 2 K].
{"title":"Cyano-bridged {LnIII 2 Fe III 2 } molecular squares (Ln = Gd, Tb, Dy, Ho, and Er): tuning the slow magnetic relaxation and magnetocaloric effects in zero-dimensional lanthanide Prussian blue analogues","authors":"Maria-Gabriela Alexandru, Diana Visinescu, Sergiu Shova, Fernando Nicolás Moliner, Mario Pacheco, Francesc Lloret","doi":"10.1039/d5qi02520f","DOIUrl":"https://doi.org/10.1039/d5qi02520f","url":null,"abstract":"An isostructural series of neutral cyano-bridged tetranuclear iron(III)-lanthanide(III) complexes of general formula {[Fe(htpzb)(CN)(μ-CN)2]2[Ln(dmbpy)(NO3<small><sub></sub></small>)2<small><sub></sub></small>(H2<small><sub></sub></small>O)]2<small><sub></sub></small>}·2CH3<small><sub></sub></small>CN·2H2<small><sub></sub></small>O [Ln = Gd (1), Tb (2), Dy (3), Ho (4), and Er (5); htpzb = hydrotris(pyrazolyl)borate and dmbpy = 4,4’-dimethyl-2,2’-bipyridine] was synthesized and structurally and magnetically characterized. Single-crystal X-ray analysis of 1-5 revealed the formation of neutral cyano-bridged {FeIII<small><sup></sup></small>2<small><sub></sub></small>LnIII<small><sup></sup></small>2<small><sub></sub></small>} complexes (Ln = Gd, Tb, Dy, Ho, and Er) of square-like topology that crystallize in the triclinic P-1 space group. Solid-state direct-current magnetic susceptibility analysis evidenced weak intramolecular antiferromagnetic FeIII<small><sup></sup></small>-LnIII<small><sup></sup></small> interactions in 1 (Ln = Gd) together with large local magnetic anisotropies from the LnIII<small><sup></sup></small> ion in 2-5 (Ln = Tb, Dy, Ho, and Er). Frequency-dependent alternating current magnetic susceptibility signals occurred for 1-5 under an applied dc magnetic field of H = 1.0 (1) or 0.5 T (2-5), indicating field-induced slow magnetic relaxation effects typical of single-molecule magnets. Depending on the non-Kramer (Tb, Ho) or Kramer (Gd, Dy, Er) nature of the LnIII<small><sup></sup></small> ion, a single magnetic relaxation process via Orbach or Raman mechanism (2 and 4) or a multiple magnetic relaxation process that combines Orbach or Raman plus quantum tunneling of magnetization and/or direct (1, 3, and 5) mechanisms occurred along this series. 1-5 showed large magnetocaloric effects with a high to moderate maximum value of the magnetic entropy change at optimum working temperatures just above He liquefaction [-ΔSmax<small><sub></sub></small> = 16.51 (1), 5.42 (2), 6.02 (3), 4.56 (4), and 5.86 J kg-1<small><sup></sup></small> K-1<small><sup></sup></small> (5) for H = 5 T at Topt<small><sub></sub></small> = Tmax<small><sub></sub></small> = 2 (1), 4 (2, 3 and 5), and 6 K (4)], as well as a high to moderate magnetocaloric index at rather low optimum working fields [MCI = 6.4 (1), 3.3 (2), 4.7 (3), 0.9 (4), and 3.6 J kg−1<small><sup></sup></small> K−1<small><sup></sup></small> T−1<small><sup></sup></small> (5) for Hopt <small><sub></sub></small>= Hmax<small><sub></sub></small> = 1.0 (1), 0.6 (2), 0.4 (3), 0.8 (4), and 0.6 T (5) at T = 2 K].","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"105 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Identifying the influencing factors and, consequently, manipulating the magnetic anisotropy are crucial for enhancing the performance of single-molecule magnets (SMMs). Using the rigid tetradentate macrocyclic host ligand 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane (L), a series of mononuclear six-coordinate Co(II) complexes with trigonal prismatic geometry, including various bidentate coligands NO3-, CH3COO-, dhbq2- (H2dhbq = 2,5-dihydroxy-1,4-benzoquinone), and AHA- (HAHA = acetohydroxamic acid), were synthesized. The target complexes [CoL(NO3)](NO3) (1), [CoL(CH3COO)](PF6) (2), [CoL(dhbq)]∙2CH3OH∙H2O (3) and [CoL(AHA)](BPh4) (4) were characterized by X-ray diffractometry, magnetic characterization, and first-principles calculation. The change of coligands triggers significant alterations in the trigonal prismatic geometries, which allows us to systematically evaluate the impacts of structural distortions. Direct current magnetic data revealed the large and negative axial zero-field splitting parameter, D, in all four complexes. Furthermore, theoretical calculations indicated that the trend in the absolute values of the D parameter follow the ordering of 1>2>3>4. Dynamic magnetic susceptibilities indicated that complexes 1−3 act as zero-field SMMs, whereas complex 4 shows slow relaxation of magnetization under the external direct current field. These results indicated that the O−Co−O bite angle is the primary factor affecting the magnetic anisotropy, while the longer Co−O bond lengths lead to the weaker ligand field, thus facilitating the spin−orbital coupling to enhance the magnetic anisotropy.
{"title":"Coligand-driven modulation of magnetic property in trigonal prismatic cobalt(II) single-ion magnets","authors":"Aoyun Zhang, Chennan Zhang, Junnan Qiao, Yawen Wang, Ulli Englert, Lei Chen, Shuchang Luo, Zhaoyang Li, Lizhuang Chen","doi":"10.1039/d5qi01722j","DOIUrl":"https://doi.org/10.1039/d5qi01722j","url":null,"abstract":"Identifying the influencing factors and, consequently, manipulating the magnetic anisotropy are crucial for enhancing the performance of single-molecule magnets (SMMs). Using the rigid tetradentate macrocyclic host ligand 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane (L), a series of mononuclear six-coordinate Co(II) complexes with trigonal prismatic geometry, including various bidentate coligands NO3-, CH3COO-, dhbq2- (H2dhbq = 2,5-dihydroxy-1,4-benzoquinone), and AHA- (HAHA = acetohydroxamic acid), were synthesized. The target complexes [CoL(NO3)](NO3) (1), [CoL(CH3COO)](PF6) (2), [CoL(dhbq)]∙2CH3OH∙H2O (3) and [CoL(AHA)](BPh4) (4) were characterized by X-ray diffractometry, magnetic characterization, and first-principles calculation. The change of coligands triggers significant alterations in the trigonal prismatic geometries, which allows us to systematically evaluate the impacts of structural distortions. Direct current magnetic data revealed the large and negative axial zero-field splitting parameter, D, in all four complexes. Furthermore, theoretical calculations indicated that the trend in the absolute values of the D parameter follow the ordering of 1>2>3>4. Dynamic magnetic susceptibilities indicated that complexes 1−3 act as zero-field SMMs, whereas complex 4 shows slow relaxation of magnetization under the external direct current field. These results indicated that the O−Co−O bite angle is the primary factor affecting the magnetic anisotropy, while the longer Co−O bond lengths lead to the weaker ligand field, thus facilitating the spin−orbital coupling to enhance the magnetic anisotropy.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"43 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiudi Yue, Junwei Wu, Honghai Liu, Anna Kaleta, Francesco Dalena, Diogenes Honorato Piva, Pierre Ruterana, Jiaqi Zhao, Zhengxing Qin, Xionghou Gao, Zifeng Yan, Svetlana Mintova
Catalytic efficiency in zeolite-based reactions critically depends on molecular diffusion kinetics within the confined channels. Nanosized ZSM-5 zeolites with a reduced b-axis thickness shorten the diffusion path and maximize the pore-opening configuration of the straight channels, enhancing mass transfer to active sites. However, achieving precise control over such nanostructures remains challenging. Herein, we report a urea-nanoseed-assisted synthesis of ZSM-5 nanoplates with low b-axis thickness in a sustainable, fluoride-free system. Comprehensive optimization of the synthesis yielded uniform crystals with a short b-axis (30–80 nm), a-axis (75–115 nm), and c-axis (130–210 nm). Mechanistic studies revealed a reversed crystal growth pathway: crystallization initiates at amorphous aggregate surfaces and propagates inward, critically directed by the organic template in the presence of urea. In methanol-to-olefin (MTO) reactions, these nanoplates outperformed commercial ZSM-5, delivering a 30% higher propylene/ethylene ratio and doubling the catalyst's lifespan. This work provides a rational strategy for synthesizing diffusion-optimized zeolites for applications where diffusion plays a critical role.
{"title":"Seeded growth of urea-promoted ZSM-5 nanoplates with short b-axis thickness for enhanced methanol-to-olefin reactions","authors":"Qiudi Yue, Junwei Wu, Honghai Liu, Anna Kaleta, Francesco Dalena, Diogenes Honorato Piva, Pierre Ruterana, Jiaqi Zhao, Zhengxing Qin, Xionghou Gao, Zifeng Yan, Svetlana Mintova","doi":"10.1039/d5qi01888a","DOIUrl":"https://doi.org/10.1039/d5qi01888a","url":null,"abstract":"Catalytic efficiency in zeolite-based reactions critically depends on molecular diffusion kinetics within the confined channels. Nanosized ZSM-5 zeolites with a reduced <em>b</em>-axis thickness shorten the diffusion path and maximize the pore-opening configuration of the straight channels, enhancing mass transfer to active sites. However, achieving precise control over such nanostructures remains challenging. Herein, we report a urea-nanoseed-assisted synthesis of ZSM-5 nanoplates with low <em>b</em>-axis thickness in a sustainable, fluoride-free system. Comprehensive optimization of the synthesis yielded uniform crystals with a short <em>b</em>-axis (30–80 nm), <em>a</em>-axis (75–115 nm), and <em>c</em>-axis (130–210 nm). Mechanistic studies revealed a reversed crystal growth pathway: crystallization initiates at amorphous aggregate surfaces and propagates inward, critically directed by the organic template in the presence of urea. In methanol-to-olefin (MTO) reactions, these nanoplates outperformed commercial ZSM-5, delivering a 30% higher propylene/ethylene ratio and doubling the catalyst's lifespan. This work provides a rational strategy for synthesizing diffusion-optimized zeolites for applications where diffusion plays a critical role.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"8 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Actinobacteria-derived o-aminophenol oxidases (AOs) represent a largely unexplored subclass of type-III copper enzymes with catalytic properties distinct from tyrosinases and catechol oxidases. The determination of the first crystal structure of an AO (SmNspF) displays unique loop insertions and important second-sphere amino acids in vicinity of the binuclear copper center. The substrate-guiding effect of the second activity controller (HisB2+1) influences the binding affinity for carboxylcontaining substrates in the AOs SmNspF and SgGriF. Thus, kinetic investigations reveal both overlapping and distinct substrate preferences for SmNspF and SgGriF: while both enzymes oxidize monophenols, o-aminophenols, and o-diphenols, they do so at significantly different reaction rates. SmNspF preferentially oxidizes carboxylated substrates such as 3,4dihydroxybenzoic acid and 3-amino-4-hydroxybenzoic acid, whereas SgGriF exhibits higher activity toward para-methylated analogs, including 4-methylcatechol and 2-amino-4-methylphenol. Remarkably, both enzymes display enzymatic activities beyond the known AO reactivity spectrum by oxidizing 2-aminoresorcinol and o-phenylenediamine, which underlies the high versatility of the binuclear copper center. Together, these findings provide a structural basis for AO's enzymatic activity and broaden the known catalytic spectrum, which enables the prediction of catalytic properties in type-III copper proteins based on their amino acid sequence.
{"title":"Structural Insights into ortho-Aminophenol Oxidase: Kinetic and Crystallographic Characterization of SmNspF and SgGriF","authors":"Hoa Le Xuan, Annette Rompel","doi":"10.1039/d5qi02495a","DOIUrl":"https://doi.org/10.1039/d5qi02495a","url":null,"abstract":"Actinobacteria-derived o-aminophenol oxidases (AOs) represent a largely unexplored subclass of type-III copper enzymes with catalytic properties distinct from tyrosinases and catechol oxidases. The determination of the first crystal structure of an AO (SmNspF) displays unique loop insertions and important second-sphere amino acids in vicinity of the binuclear copper center. The substrate-guiding effect of the second activity controller (HisB2+1) influences the binding affinity for carboxylcontaining substrates in the AOs SmNspF and SgGriF. Thus, kinetic investigations reveal both overlapping and distinct substrate preferences for SmNspF and SgGriF: while both enzymes oxidize monophenols, o-aminophenols, and o-diphenols, they do so at significantly different reaction rates. SmNspF preferentially oxidizes carboxylated substrates such as 3,4dihydroxybenzoic acid and 3-amino-4-hydroxybenzoic acid, whereas SgGriF exhibits higher activity toward para-methylated analogs, including 4-methylcatechol and 2-amino-4-methylphenol. Remarkably, both enzymes display enzymatic activities beyond the known AO reactivity spectrum by oxidizing 2-aminoresorcinol and o-phenylenediamine, which underlies the high versatility of the binuclear copper center. Together, these findings provide a structural basis for AO's enzymatic activity and broaden the known catalytic spectrum, which enables the prediction of catalytic properties in type-III copper proteins based on their amino acid sequence.","PeriodicalId":79,"journal":{"name":"Inorganic Chemistry Frontiers","volume":"113 1","pages":""},"PeriodicalIF":7.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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