The separation and recovery of neptunium (Np) represents a critical challenge in nuclear waste reprocessing. To address the difficulty of effectively capturing Np(V) in conventional extraction systems, this study designed and constructed three hydrophobic deep eutectic solvents (DESs) using tri-n-octylphosphine oxide (TOPO) as the hydrogen bond acceptor (HBA) and dihydroxybenzene isomers (catechol, CC; resorcinol, RC; hydroquinone, HQ) as hydrogen bond donors (HBD). These DESs enabled the in-situ reduction at the liquid-liquid interface and highly efficient extraction of Np(V). Among them, the TOPO-CC DES system exhibited outstanding extraction performance for Np(V) over a broad acidity range of 10 -3 to 2.0 M HNO3, achieving a single-stage distribution ratio (DNp) up to 85 and an in-situ reduction conversion ratio from Np(V) to Np(IV) exceeding 98% within 5 minutes. Mechanistic investigations revealed that the extraction process follows a "coordinationdriven reduction" mechanism. TOPO initially forms a weak coordination intermediate with Np(V) at the interface, thereby lowering its reduction potential. Subsequently, the dihydroxybenzene component facilitates efficient electron transfer within the organic phase, reducing Np(V) to Np(IV), which is strongly complexed and extracted by TOPO, completing an integrated "coordination-reduction-extraction" process. Furthermore, this system maintained stable extraction performance under challenging conditions, including high salinity (1-5 M NaNO3), a wide temperature range (293-313 K), and significant cumulative γ irradiation doses (up to 60 kGy). This study provides a novel integrated DES strategy for the efficient and green recovery of Np(V) and lays a scientific foundation for the application of functionalized deep eutectic solvents in advanced nuclear fuel cycles.
镎（Np）的分离和回收是核废料后处理中的一个关键挑战。为了解决传统萃取体系中有效捕获Np(V)的困难，本研究设计并构建了三种疏水深共晶溶剂（DESs），以三正辛烷基膦氧化物（TOPO）为氢键受体（HBA），二羟基异构体（儿茶酚，CC；间苯二酚，RC；对苯二酚，HQ）为氢键供体（HBD）。这些DESs实现了液-液界面的原位还原和Np(V)的高效萃取。其中，TOPO-CC DES体系在10 -3 ~ 2.0 M HNO3酸性范围内对Np(V)的萃取性能优异，单级分配比（DNp）高达85,5分钟内Np(V)到Np（IV）的原位还原转化率超过98%。机理研究表明，提取过程遵循“协调驱动还原”机制。TOPO最初在界面处与Np(V)形成弱配位中间体，从而降低了其还原电位。随后，二羟基苯组分促进有机相内的高效电子转移，将Np(V)还原为Np(IV)，并被TOPO强络合提取，完成了一个完整的“配位-还原-萃取”过程。此外，该系统在高盐度（1-5 M NaNO3）、宽温度范围（293-313 K）和显著的累积γ辐射剂量（高达60 kGy）等挑战性条件下保持稳定的提取性能。本研究为高效绿色回收Np(V)提供了一种新的集成DES策略，为功能化深共晶溶剂在先进核燃料循环中的应用奠定了科学基础。
{"title":"Efficient In-Situ Reduction and Recovery of Neptunium(V) Using Redox-Functionalized Deep Eutectic Solvents","authors":"Lin Zhang, Qilong Tang, Zhipeng Wang, Chao Xu","doi":"10.1039/d5dt03100a","DOIUrl":"https://doi.org/10.1039/d5dt03100a","url":null,"abstract":"The separation and recovery of neptunium (Np) represents a critical challenge in nuclear waste reprocessing. To address the difficulty of effectively capturing Np(V) in conventional extraction systems, this study designed and constructed three hydrophobic deep eutectic solvents (DESs) using tri-n-octylphosphine oxide (TOPO) as the hydrogen bond acceptor (HBA) and dihydroxybenzene isomers (catechol, CC; resorcinol, RC; hydroquinone, HQ) as hydrogen bond donors (HBD). These DESs enabled the in-situ reduction at the liquid-liquid interface and highly efficient extraction of Np(V). Among them, the TOPO-CC DES system exhibited outstanding extraction performance for Np(V) over a broad acidity range of 10 -3 to 2.0 M HNO3, achieving a single-stage distribution ratio (DNp) up to 85 and an in-situ reduction conversion ratio from Np(V) to Np(IV) exceeding 98% within 5 minutes. Mechanistic investigations revealed that the extraction process follows a \"coordinationdriven reduction\" mechanism. TOPO initially forms a weak coordination intermediate with Np(V) at the interface, thereby lowering its reduction potential. Subsequently, the dihydroxybenzene component facilitates efficient electron transfer within the organic phase, reducing Np(V) to Np(IV), which is strongly complexed and extracted by TOPO, completing an integrated \"coordination-reduction-extraction\" process. Furthermore, this system maintained stable extraction performance under challenging conditions, including high salinity (1-5 M NaNO3), a wide temperature range (293-313 K), and significant cumulative γ irradiation doses (up to 60 kGy). This study provides a novel integrated DES strategy for the efficient and green recovery of Np(V) and lays a scientific foundation for the application of functionalized deep eutectic solvents in advanced nuclear fuel cycles.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"4 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070566","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}
Ru-based thin films are essential for electronics and catalysis. Their growth through atomic layer deposition (ALD) depends on precursors that balance reactivity, volatility, and thermal stability. We present the first Ru dicarbonyl bisamidate complexes as a new and promising class of ALD precursors for Ru-based materials. Modifying the substitution pattern of the amidate ligands yielded [Ru(CO)2(N-sBuiPrAD)2], as a volatile liquid precursor with excellent thermal properties. First principles simulations predict favorable interactions with common ALD co-reactants, indicating its potential for thin film deposition.
{"title":"Ruthenium(II) carbonyl amidates - a new class of precursors for atomic layer deposition.","authors":"Jorit Obenlüneschloß,Cara-Lena Nies,Michael Gock,Michael Unkrig-Bau,Jan-Niklas Huster,Michael Nolan,Anjana Devi","doi":"10.1039/d5dt02610e","DOIUrl":"https://doi.org/10.1039/d5dt02610e","url":null,"abstract":"Ru-based thin films are essential for electronics and catalysis. Their growth through atomic layer deposition (ALD) depends on precursors that balance reactivity, volatility, and thermal stability. We present the first Ru dicarbonyl bisamidate complexes as a new and promising class of ALD precursors for Ru-based materials. Modifying the substitution pattern of the amidate ligands yielded [Ru(CO)2(N-sBuiPrAD)2], as a volatile liquid precursor with excellent thermal properties. First principles simulations predict favorable interactions with common ALD co-reactants, indicating its potential for thin film deposition.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"87 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146056360","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}
Crystallographic databases are vital for research and increasingly serve as training data for machine learning in materials discovery, yet systematic quality assessment at database scale remains absent. Bond valence sum (BVS) analysis -testing whether calculated bond valences match expected oxidation states -provides one automated quality metric, but has not been systematically applied to quantify validation rates, characterise failure modes, or identify parameter inadequacies. Eir is an automated Python tool for high-throughput BVS analysis, applied here to 840 rock salt structures from the Inorganic Crystal Structure Database. Of 686 assessable structures, 49.5% validated under ambient data collection conditions, with systematic examination leaving no unexplained outliers. Failed structures stratify into six categories: systematic parameter inadequacy (17.1%), methodological limitations from diffraction-averaged geometries (10.5%), and database quality issues (2.4%). Three main findings emerged: (1) alkaline earth oxides exhibit systematic parameter inadequacy (CaO, SrO, BaO: 100% failure, <1.5% variance); (2) oxide-chalcogenide validation inversion demonstrates anion-specific parameter quality;(3) multi-phase refinement contamination shows structures passing peer review may prove inappropriate as computational references. The open-source tool provides validated infrastructure for maintaining database integrity as crystallographic repositories serve AI-driven materials discovery at unprecedented scale.
{"title":"Automated Bond Valence Sum Analysis for Crystallographic Database Quality Assessment: A Systematic Study of Rock Salt Oxides, Halides, and Chalcogenides","authors":"Nik Reeves-McLaren","doi":"10.1039/d5dt03003j","DOIUrl":"https://doi.org/10.1039/d5dt03003j","url":null,"abstract":"Crystallographic databases are vital for research and increasingly serve as training data for machine learning in materials discovery, yet systematic quality assessment at database scale remains absent. Bond valence sum (BVS) analysis -testing whether calculated bond valences match expected oxidation states -provides one automated quality metric, but has not been systematically applied to quantify validation rates, characterise failure modes, or identify parameter inadequacies. Eir is an automated Python tool for high-throughput BVS analysis, applied here to 840 rock salt structures from the Inorganic Crystal Structure Database. Of 686 assessable structures, 49.5% validated under ambient data collection conditions, with systematic examination leaving no unexplained outliers. Failed structures stratify into six categories: systematic parameter inadequacy (17.1%), methodological limitations from diffraction-averaged geometries (10.5%), and database quality issues (2.4%). Three main findings emerged: (1) alkaline earth oxides exhibit systematic parameter inadequacy (CaO, SrO, BaO: 100% failure, <1.5% variance); (2) oxide-chalcogenide validation inversion demonstrates anion-specific parameter quality;(3) multi-phase refinement contamination shows structures passing peer review may prove inappropriate as computational references. The open-source tool provides validated infrastructure for maintaining database integrity as crystallographic repositories serve AI-driven materials discovery at unprecedented scale.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"26 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057087","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}
Novel bifunctional nanosystems consisting of magnetic resonance imaging (MRI) nanocontrast agents and chemotherapeutic drugs have potential for detecting and treating cancers. In this study, magnetite nanoparticles were coated with an inorganic/organic (metakaolin/polyethylene glycol (PEG)) compound to prepare a bilayer nanocomposite (FKP). The nanocomposite was loaded with 5-fluorouracil (5FU) to investigate 5FU-FKP transverse relaxivity for MRI contrast enhancement and in vitro 5FU loading/release. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and thermogravimetric analyses (TGA) were used to determine the physicochemical characteristics of the nanocomposite. Cytotoxicity was investigated by the MTT assay. The 5FU loading and release studies demonstrated a high drug loading efficiency (97.4%) and sustained pH-dependent drug release of 81.3% and 91.7% at pH of 7.4 and 5.0 after 96 h, respectively. The superparamagnetic 5FU-FKP nanocomposite indicated high transverse relaxivity (r2 = 558.4 mM-1 s-1) as a negative contrast agent of MRI. The MTT evaluation revealed the cytocompatibility of the surface-coated Fe3O4 nanoparticles (FKP nanocomposite) and the higher cytotoxicity of 5FU-FKP compared to free 5FU. Therefore, the 5FU-FKP nanocomposite can be considered a potential candidate for MRI and 5FU delivery.
{"title":"Bilayer inorganic/organic metakaolin/polyethylene glycol-coated magnetite nanoparticles: MRI transverse relaxivity, cytocompatibility, and 5-fluorouracil release behavior.","authors":"Baharak Divband,Shaimaa Sabte Mutlak,Sahba Mofazal,Nahideh Gharehaghaji","doi":"10.1039/d5dt01921d","DOIUrl":"https://doi.org/10.1039/d5dt01921d","url":null,"abstract":"Novel bifunctional nanosystems consisting of magnetic resonance imaging (MRI) nanocontrast agents and chemotherapeutic drugs have potential for detecting and treating cancers. In this study, magnetite nanoparticles were coated with an inorganic/organic (metakaolin/polyethylene glycol (PEG)) compound to prepare a bilayer nanocomposite (FKP). The nanocomposite was loaded with 5-fluorouracil (5FU) to investigate 5FU-FKP transverse relaxivity for MRI contrast enhancement and in vitro 5FU loading/release. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and thermogravimetric analyses (TGA) were used to determine the physicochemical characteristics of the nanocomposite. Cytotoxicity was investigated by the MTT assay. The 5FU loading and release studies demonstrated a high drug loading efficiency (97.4%) and sustained pH-dependent drug release of 81.3% and 91.7% at pH of 7.4 and 5.0 after 96 h, respectively. The superparamagnetic 5FU-FKP nanocomposite indicated high transverse relaxivity (r2 = 558.4 mM-1 s-1) as a negative contrast agent of MRI. The MTT evaluation revealed the cytocompatibility of the surface-coated Fe3O4 nanoparticles (FKP nanocomposite) and the higher cytotoxicity of 5FU-FKP compared to free 5FU. Therefore, the 5FU-FKP nanocomposite can be considered a potential candidate for MRI and 5FU delivery.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"41 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146056931","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}
Atharva Y. Kulkarni, Dwaipayan Majumder, Sandeep Nigam, V. S. Tripathi, A. P. Wadawale, Jitendra Bahadur, Ankita Pathak, Gourab Karmakar, Rohit Singh Chauhan, Adish Tyagi
Designing molecular precursors for the controlled synthesis of functional nanomaterials holds immense promise for advancing sustainable energy technologies. Herein, we report the synthesis and structural characterization of an air-stable bismuth(III) complex, [(L)₂BiCl₂(μ-Cl)]₂ (1), derived from 3-benzyl-1-methyl-(1H)-imidazole-2(3H)-selone (L). This complex serves as an efficient single-source molecular precursor (SSP) for the facile preparation of rhombohedral Bi₂Se₃ nanostructures under mild conditions. Plausible mechanism behind the facile decomposition of the molecular complex into Bi2Se3 materials has been discussed. Powder X-ray diffraction (PXRD), electron microscopy, and diffuse reflectance spectroscopy (DRS) confirm the phase purity, crystal structure, and optical properties of the nanomaterials. Notably, reaction conditions significantly influenced the morphology, yielding nanoplates under solventless decomposition and nanosheets under solvent-assisted thermolysis. These Bi₂Se₃ nanostructures exhibit optical bandgaps of ̴1.56 eV (nanoplates) and ̴1.60 eV (nanosheets), highlighting their potential in optoelectronic and catalytic applications. Notably, the Bi₂Se₃ nanoplates demonstrate excellent HER performance, achieving an overpotential of 372 mV at -10 mA cm⁻², a Tafel slope of ~62 mV dec⁻¹, and robust stability over 2000 cycles and 18 hours of continuous operation. Density functional theory (DFT) calculations reveal that surface charge heterogeneity at the exposed Bi₂Se₃ layers which is expected to enhance the absorption of polar species. This study highlights the significance of molecular precursor strategy for controlled synthesis of efficient Bi₂Se₃-based electrocatalysts for sustainable hydrogen production in neutral aqueous environments.
为功能纳米材料的受控合成设计分子前体对推进可持续能源技术具有巨大的希望。本文报道了由3-苄基-1-甲基-(1H)-咪唑-2(3H)-selone (L)衍生的空气稳定铋（III）配合物[(L)₂BiCl₂（μ-Cl）]₂(1)的合成和结构表征。该配合物作为一种有效的单源分子前体（SSP），在温和的条件下可以轻松制备菱形Bi₂Se₃纳米结构。讨论了分子络合物容易分解成Bi2Se3材料的合理机制。粉末x射线衍射（PXRD）、电子显微镜和漫反射光谱（DRS）证实了纳米材料的相纯度、晶体结构和光学性能。值得注意的是，反应条件显著影响形貌，在无溶剂分解下生成纳米板，在溶剂辅助热裂解下生成纳米片。这些Bi₂Se₃纳米结构的光学带隙为1.56 eV（纳米片）和1.60 eV（纳米片），突出了它们在光电和催化应用方面的潜力。值得注意的是，Bi₂Se₃纳米板表现出优异的HER性能，在-10 mA cm⁻²时的过电位为372 mV，塔菲斜率为~62 mV dec⁻¹，并且在2000次循环和18小时的连续运行中具有很强的稳定性。密度泛函理论（DFT）计算表明，暴露的Bi₂Se₃层表面电荷的非均质性有望增强极性物质的吸收。该研究强调了分子前体策略对控制合成高效Bi₂Se₃基电催化剂的意义，该催化剂用于在中性水环境中可持续制氢。
{"title":"Novel bismuth-selone molecular precursor based selective synthesis of Bi2Se3 nanoplates and nanosheets: A promising electrocatalyst for hydrogen evolution in neutral medium","authors":"Atharva Y. Kulkarni, Dwaipayan Majumder, Sandeep Nigam, V. S. Tripathi, A. P. Wadawale, Jitendra Bahadur, Ankita Pathak, Gourab Karmakar, Rohit Singh Chauhan, Adish Tyagi","doi":"10.1039/d6dt00093b","DOIUrl":"https://doi.org/10.1039/d6dt00093b","url":null,"abstract":"Designing molecular precursors for the controlled synthesis of functional nanomaterials holds immense promise for advancing sustainable energy technologies. Herein, we report the synthesis and structural characterization of an air-stable bismuth(III) complex, [(L)₂BiCl₂(μ-Cl)]₂ (1), derived from 3-benzyl-1-methyl-(1H)-imidazole-2(3H)-selone (L). This complex serves as an efficient single-source molecular precursor (SSP) for the facile preparation of rhombohedral Bi₂Se₃ nanostructures under mild conditions. Plausible mechanism behind the facile decomposition of the molecular complex into Bi2Se3 materials has been discussed. Powder X-ray diffraction (PXRD), electron microscopy, and diffuse reflectance spectroscopy (DRS) confirm the phase purity, crystal structure, and optical properties of the nanomaterials. Notably, reaction conditions significantly influenced the morphology, yielding nanoplates under solventless decomposition and nanosheets under solvent-assisted thermolysis. These Bi₂Se₃ nanostructures exhibit optical bandgaps of ̴1.56 eV (nanoplates) and ̴1.60 eV (nanosheets), highlighting their potential in optoelectronic and catalytic applications. Notably, the Bi₂Se₃ nanoplates demonstrate excellent HER performance, achieving an overpotential of 372 mV at -10 mA cm⁻², a Tafel slope of ~62 mV dec⁻¹, and robust stability over 2000 cycles and 18 hours of continuous operation. Density functional theory (DFT) calculations reveal that surface charge heterogeneity at the exposed Bi₂Se₃ layers which is expected to enhance the absorption of polar species. This study highlights the significance of molecular precursor strategy for controlled synthesis of efficient Bi₂Se₃-based electrocatalysts for sustainable hydrogen production in neutral aqueous environments.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"55 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057088","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}
Nikoleta Malinova, Jan Pavlik, Kamil Kotrle, Ivan Nemec, Tibor Dubaj, Barbora Brachnakova, Mario Ruben, Ivan Salitros
We report the synthesis, crystal structures, and magnetic properties of three Co(II) and two Ln(III) (Dy, Tb) complexes, all containing the tridentate ligand 2,6-bis(3-methoxypropyl-1H-benzimidazol-2-yl)pyridine (L). The pentacoordinate Co(II) complexes [Co(L)Cl2] (1) and [Co(L)Br2] (2) adopt distorted square-pyramidal geometries, while the heptacoordinate complexes [Co(L)(κ²-NO₃)₂] (3) contain two independent complex molecules with capped trigonal prismatic and pentagonal bipyramidal shape of polyhedra. Lanthanide complexes [Dy(L)Cl₃(H₂O)] (4) and [Tb(L)Cl₃(H₂O)] (5) also adopt pentagonal-bipyramidal coordination environments and display characteristic 4f–4f emission bands in the solid state at 3 K. Ab initio calculations reproduce the observed anisotropy trends and rationalize the magnetic behaviour. Pentacoordinate Co(II) centres require explicit Griffith–Figgis Hamiltonian approach, while heptacoordinate Co(II) complex 3 exhibits axial anisotropy rationalised by spin Hamiltonian formalism. Analysis of static magnetic properties of complexes 4 and 5 also revealed the notable magnetic anisotropy and zero-field splitting of the Ln(III) ions. AC susceptibility measurements reveal field-supported slow relaxation of magnetisation (SRM) in 1–4, with complexes 1–3 exhibiting single-channel relaxation and 4 displaying two relaxation pathways. In contrast, compound 5 shows no evidence of SRM. Analysis of the temperature dependence of the relaxation times yielded effective energy barriers (Ueff) of 15.9(7) K for 1, 25.0(5) K for 2, 27(1) K for 3, and 33(3) K for 4. Comparative analysis across 3d and 4f systems highlights the crucial role of subtle ligand-field distortions and donor charge distribution in governing SIM performance. These findings expand the chemistry of pyridyl-benzimidazole-derived ligands and provide new design principles for both transition-metal and lanthanide single-ion magnets.
{"title":"Unveiling Field-Induced Single-Ion Magnetism in Pentacoordinate and Heptacoordinate Cobalt(II), Dysprosium(III) and Terbium(III) Complexes with Tridentate Bis(Benzimidazole)Pyridine Ligand","authors":"Nikoleta Malinova, Jan Pavlik, Kamil Kotrle, Ivan Nemec, Tibor Dubaj, Barbora Brachnakova, Mario Ruben, Ivan Salitros","doi":"10.1039/d5dt02849c","DOIUrl":"https://doi.org/10.1039/d5dt02849c","url":null,"abstract":"We report the synthesis, crystal structures, and magnetic properties of three Co(II) and two Ln(III) (Dy, Tb) complexes, all containing the tridentate ligand 2,6-bis(3-methoxypropyl-1H-benzimidazol-2-yl)pyridine (L). The pentacoordinate Co(II) complexes [Co(L)Cl2] (1) and [Co(L)Br2] (2) adopt distorted square-pyramidal geometries, while the heptacoordinate complexes [Co(L)(κ²-NO₃)₂] (3) contain two independent complex molecules with capped trigonal prismatic and pentagonal bipyramidal shape of polyhedra. Lanthanide complexes [Dy(L)Cl₃(H₂O)] (4) and [Tb(L)Cl₃(H₂O)] (5) also adopt pentagonal-bipyramidal coordination environments and display characteristic 4f–4f emission bands in the solid state at 3 K. Ab initio calculations reproduce the observed anisotropy trends and rationalize the magnetic behaviour. Pentacoordinate Co(II) centres require explicit Griffith–Figgis Hamiltonian approach, while heptacoordinate Co(II) complex 3 exhibits axial anisotropy rationalised by spin Hamiltonian formalism. Analysis of static magnetic properties of complexes 4 and 5 also revealed the notable magnetic anisotropy and zero-field splitting of the Ln(III) ions. AC susceptibility measurements reveal field-supported slow relaxation of magnetisation (SRM) in 1–4, with complexes 1–3 exhibiting single-channel relaxation and 4 displaying two relaxation pathways. In contrast, compound 5 shows no evidence of SRM. Analysis of the temperature dependence of the relaxation times yielded effective energy barriers (Ueff) of 15.9(7) K for 1, 25.0(5) K for 2, 27(1) K for 3, and 33(3) K for 4. Comparative analysis across 3d and 4f systems highlights the crucial role of subtle ligand-field distortions and donor charge distribution in governing SIM performance. These findings expand the chemistry of pyridyl-benzimidazole-derived ligands and provide new design principles for both transition-metal and lanthanide single-ion magnets.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"58 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070570","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}
Jens-Georg Becker, Sriram Sundaresan, Tim Hochdörffer, Juliusz A Wolny, Luca Carrella, Volker Schünemann, Eva Rentschler
Understanding the role of co-ligand identity, governing spin-state energetics in many Fe(II) complexes, is essential for designing responsive spin-crossover materials. We report the synthesis of an unsymmetrical bis(pyridin-2-ylmethyl)glycyl benzohydrazide-derived ligand, 1-(5-phenyl-1,3,4-thiadiazol-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine (LPh-TDA), and its corresponding complexes [Fe(LPh-TDA)(NCE) 2 ]•H 2 O (E = S (C1), Se (C2), BH3 (C3)). While the ligand-field strength gradient ranges from weak (NCS-) to strong (NCBH3-), the SCO behaviour of the resulting complexes does not reflect this. Variable-temperature single-crystal X-ray diffraction, SQUID magnetometry and ⁵⁷Fe Mössbauer spectroscopy show that there is packing-induced sublattice spin-state ordering for C1, which has two distinct Fe(II) sites. Of these sites, only one transitions to the low-spin state in two complexes, while the second remains locked in the high-spin (HS) state. C2 remains high-spin throughout the entire temperature range, whereas C3 exhibits a complete, one-step SCO with T1/2 = 153 K. Density functional theory (DFT) calculations help to quantify the energetic origin of the ordered LS-HS configuration in C1 and demonstrate that intermolecular packing effects override intrinsic ligand-field trends. These results highlight the dominant role of solid-state organization in dictating SCO behavior, even in systems engineered to isolate co-ligand electronic effects.
了解共配体同一性的作用，控制许多Fe（II）配合物的自旋态能量学，对于设计响应性自旋交叉材料至关重要。本文报道了一种非对称双（吡啶-2-甲基）甘酰基苯并肼衍生物配体1-（5-苯基-1,3,4-噻二唑-2-基）- n， n-双（吡啶-2-甲基）甲胺（LPh-TDA）及其相应配合物[Fe(LPh-TDA)(NCE) 2]•h2o (E = S (C1), Se （C2), BH3 (C3)）的合成。虽然配体场强度梯度从弱（NCS-）到强（NCBH3-）不等，但所得到的配合物的SCO行为并不反映这一点。变温单晶x射线衍射、SQUID磁强计和5⁷Fe Mössbauer光谱显示，C1存在填充诱导的亚晶格自旋态有序，其具有两个不同的Fe（II）位点。在这些位点中，只有一个在两个配合物中过渡到低自旋态，而另一个仍然锁定在高自旋（HS）态。C2在整个温度范围内保持高自旋，而C3在T1/2 = 153 K时表现出完整的一步SCO。密度泛函理论（DFT）计算有助于量化C1中有序LS-HS结构的能量起源，并证明分子间填充效应超越了本然配体场趋势。这些结果突出了固态组织在决定SCO行为方面的主导作用，即使在设计用于隔离共配体电子效应的系统中也是如此。
{"title":"Sub Lattice Driven Spin State Ordering and Coordination Elasticity in Fe(II) 1,3,4-Thiadiazole Complexes","authors":"Jens-Georg Becker, Sriram Sundaresan, Tim Hochdörffer, Juliusz A Wolny, Luca Carrella, Volker Schünemann, Eva Rentschler","doi":"10.1039/d5dt02912k","DOIUrl":"https://doi.org/10.1039/d5dt02912k","url":null,"abstract":"Understanding the role of co-ligand identity, governing spin-state energetics in many Fe(II) complexes, is essential for designing responsive spin-crossover materials. We report the synthesis of an unsymmetrical bis(pyridin-2-ylmethyl)glycyl benzohydrazide-derived ligand, 1-(5-phenyl-1,3,4-thiadiazol-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine (LPh-TDA<small><sup></sup></small>), and its corresponding complexes [Fe(LPh-TDA<small><sup></sup></small>)(NCE) <small><sub>2</sub></small> ]•H <small><sub>2</sub></small> O (E = S (<strong>C1</strong>), Se (<strong>C2</strong>), BH<small><sub>3</sub></small> (<strong>C3</strong>)). While the ligand-field strength gradient ranges from weak (NCS<small><sup>-</sup></small>) to strong (NCBH<small><sub>3</sub></small><small><sup>-</sup></small>), the SCO behaviour of the resulting complexes does not reflect this. Variable-temperature single-crystal X-ray diffraction, SQUID magnetometry and ⁵⁷Fe Mössbauer spectroscopy show that there is packing-induced sublattice spin-state ordering for <strong>C1</strong>, which has two distinct Fe(II) sites. Of these sites, only one transitions to the low-spin state in two complexes, while the second remains locked in the high-spin (HS) state. <strong>C2</strong> remains high-spin throughout the entire temperature range, whereas <strong>C3 </strong>exhibits a complete, one-step SCO with T<small><sub>1/2</sub></small> = 153 K. Density functional theory (DFT) calculations help to quantify the energetic origin of the ordered LS-HS configuration in <strong>C1</strong> and demonstrate that intermolecular packing effects override intrinsic ligand-field trends. These results highlight the dominant role of solid-state organization in dictating SCO behavior, even in systems engineered to isolate co-ligand electronic effects.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"28 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057102","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}
Ömer Güngör,Neşe Taşci,Ayça Şeyma Ünaldı,Mahmut Durmuş
In this study, a novel subphthalocyanine-substituted calix[4]arene (Calix-Sub) fluorophore was designed and synthesized. Its structure was characterized by FT-IR, MALDI-TOF, 1H-NMR, and elemental analyses. Calixarenes are promising sensors due to their rigid structures, complexation abilities, and selectivity, while subphthalocyanine provides strong fluorescence behaviour. The Calix-Sub sensor exhibited a "turn-off" fluorescence response toward Cu(II) ions and a "turn-on" response upon addition of tebuconazole pesticide, demonstrating its potential as an optical sensor. The system enabled quantification of tebuconazole in a linear range of 0.33-2.05 mmol L-1 with a detection limit of 0.53 mmol L-1. The sensor showed high selectivity and a clear fluorescence response toward tebuconazole over other metal ions and pesticides. Analytical parameters, including selectivity, precision, sensitivity, and recovery were optimized for environmental sample analysis.
{"title":"A dual-mode subphthalocyanine-functionalized calix[4]arene based turn-off-on fluorescent sensor for selective detection of tebuconazole pesticide in food and water samples.","authors":"Ömer Güngör,Neşe Taşci,Ayça Şeyma Ünaldı,Mahmut Durmuş","doi":"10.1039/d5dt02794b","DOIUrl":"https://doi.org/10.1039/d5dt02794b","url":null,"abstract":"In this study, a novel subphthalocyanine-substituted calix[4]arene (Calix-Sub) fluorophore was designed and synthesized. Its structure was characterized by FT-IR, MALDI-TOF, 1H-NMR, and elemental analyses. Calixarenes are promising sensors due to their rigid structures, complexation abilities, and selectivity, while subphthalocyanine provides strong fluorescence behaviour. The Calix-Sub sensor exhibited a \"turn-off\" fluorescence response toward Cu(II) ions and a \"turn-on\" response upon addition of tebuconazole pesticide, demonstrating its potential as an optical sensor. The system enabled quantification of tebuconazole in a linear range of 0.33-2.05 mmol L-1 with a detection limit of 0.53 mmol L-1. The sensor showed high selectivity and a clear fluorescence response toward tebuconazole over other metal ions and pesticides. Analytical parameters, including selectivity, precision, sensitivity, and recovery were optimized for environmental sample analysis.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"30 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146056930","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 synthesis of novel two-dimensional (2D) triangular frustrated compounds are important for providing various platforms to investigate exotic quantum magnetism. Here, we successfully synthesised a series of RE-based magnetic compounds Ba3BiPbREO(BO3)4 (RE = Pr, Nd, Gd, Dy) with a geometrically-perfect 2D triangular lattice directed by triangular BO3 unit. These compounds stabilise 2D layered structures in the hexagonal (P63/mmc) crystal system, where magnetic ions are linked by BO3 to form a perfect triangular frustrated lattice. The magnetisation susceptibility results show that all synthesised compounds Ba3BiPbREO(BO3)4 exhibit dominant antiferromagnetic (AFM) interactions, with no long-range order (LRO) down to 2 K, which is further confirmed by specific heat measurements. Additionally, their thermal stability, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) and Ultraviolet−visible-near-infrared (UV−Vis−NIR) diffuse reflectance spectra are also reported. This work provides a series of RE-based magnetic compounds with a two-dimensional triangular frustrated lattice, offering novel model materials for further investigation on rare-earth-based frustrated magnetism.
{"title":"Ba3BiPbREO(BO3)4 (RE =Pr, Nd, Gd, Dy): Two-Dimensional Rare-Earth Antiferromagnets with Geometrically-Perfect Triangular Lattice Directed by Triangular BO3 Unit","authors":"Yun Lv, Yanhong Wang, Nian Shi, Keke Huang, Jinkui Tang, Hongcheng Lu","doi":"10.1039/d5dt03066h","DOIUrl":"https://doi.org/10.1039/d5dt03066h","url":null,"abstract":"The synthesis of novel two-dimensional (2D) triangular frustrated compounds are important for providing various platforms to investigate exotic quantum magnetism. Here, we successfully synthesised a series of RE-based magnetic compounds Ba3BiPbREO(BO3)4 (RE = Pr, Nd, Gd, Dy) with a geometrically-perfect 2D triangular lattice directed by triangular BO3 unit. These compounds stabilise 2D layered structures in the hexagonal (P63/mmc) crystal system, where magnetic ions are linked by BO3 to form a perfect triangular frustrated lattice. The magnetisation susceptibility results show that all synthesised compounds Ba3BiPbREO(BO3)4 exhibit dominant antiferromagnetic (AFM) interactions, with no long-range order (LRO) down to 2 K, which is further confirmed by specific heat measurements. Additionally, their thermal stability, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) and Ultraviolet−visible-near-infrared (UV−Vis−NIR) diffuse reflectance spectra are also reported. This work provides a series of RE-based magnetic compounds with a two-dimensional triangular frustrated lattice, offering novel model materials for further investigation on rare-earth-based frustrated magnetism.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"78 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057086","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}
Christina Siakalli, Bradley Edward Osborne, Ryan Brown, Claudia Rocco, Dominik Weiss, Enrique García-España, Pascal Grundler, Anzhelika Moiseeva, Zeynep Talip, Nicholas P. van der Meulen, Michelle Ma, Nicholas J Long
Emerging therapeutic radiolanthanides have utility for systemic molecular radiotherapy in nuclear medicine, provided that suitable chemical technology is available to incorporate them into receptor-targeted radiopharmaceuticals. In this work, N,N’-bis(8-hydroxyquinoline-2-ylmethyl)-4,13-diaza-18-crown-6 (H2KHQ) was synthesised, and its binding ability, thermodynamic stability and selectivity for Ln3+ ions (Ln3+ = La, Tb, and Lu) investigated. The design of H2KHQ involves pendant arms featuring 8-hydroxyquinoline units, known to possess metal-chelating properties and desirable activity in other therapeutic molecules. H2KHQ exhibited selectivity for the larger Ln3+ ions, confirmed by experimentally measured stability constants as well as DFT calculations. H2KHQ was able to bind the larger, non-radioactive La3+ and Tb3+ ions within 30 minutes at room temperature, forming a single, 2-fold symmetric species in solution. The structure of [La-HKHQ]2+, as determined by single crystal XRD, emphasized the need for high denticity chelators to satisfy the coordination sphere of the Ln3+, showing a 10-coordinate La3+ metal centre. H2KHQ was radiolabelled with [161Tb]TbCl3 under mild conditions in 92 % radiochemical yield in promising proof-of-concept measurements.
{"title":"Hydroxyquinoline-functionalised aza-crown macrocycles for lanthanide coordination","authors":"Christina Siakalli, Bradley Edward Osborne, Ryan Brown, Claudia Rocco, Dominik Weiss, Enrique García-España, Pascal Grundler, Anzhelika Moiseeva, Zeynep Talip, Nicholas P. van der Meulen, Michelle Ma, Nicholas J Long","doi":"10.1039/d5dt03015c","DOIUrl":"https://doi.org/10.1039/d5dt03015c","url":null,"abstract":"Emerging therapeutic radiolanthanides have utility for systemic molecular radiotherapy in nuclear medicine, provided that suitable chemical technology is available to incorporate them into receptor-targeted radiopharmaceuticals. In this work, N,N’-bis(8-hydroxyquinoline-2-ylmethyl)-4,13-diaza-18-crown-6 (H2KHQ) was synthesised, and its binding ability, thermodynamic stability and selectivity for Ln3+ ions (Ln3+ = La, Tb, and Lu) investigated. The design of H2KHQ involves pendant arms featuring 8-hydroxyquinoline units, known to possess metal-chelating properties and desirable activity in other therapeutic molecules. H2KHQ exhibited selectivity for the larger Ln3+ ions, confirmed by experimentally measured stability constants as well as DFT calculations. H2KHQ was able to bind the larger, non-radioactive La3+ and Tb3+ ions within 30 minutes at room temperature, forming a single, 2-fold symmetric species in solution. The structure of [La-HKHQ]2+, as determined by single crystal XRD, emphasized the need for high denticity chelators to satisfy the coordination sphere of the Ln3+, showing a 10-coordinate La3+ metal centre. H2KHQ was radiolabelled with [161Tb]TbCl3 under mild conditions in 92 % radiochemical yield in promising proof-of-concept measurements.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070569","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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