Crystal Growth & Design最新文献

{"title":"High-Luminance Red Ba2CaB2Si4O14: Eu3+ with “Abnormal” Thermal Stability and Adjustable Photoluminescence from Defect Regulation and Energy Transfer via Dy3+ Codoping for “Warm” Illumination and Pressure Sensing Applications","authors":"Kaiting Wu,&nbsp;Pengju Xia,&nbsp;Chengyu Ni,&nbsp;Wanyuan Li,&nbsp;Man Xu and Wubin Dai*,&nbsp;","doi":"10.1021/acs.cgd.5c0023210.1021/acs.cgd.5c00232","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00232https://doi.org/10.1021/acs.cgd.5c00232","url":null,"abstract":"<p >In pursuit of illumination-grade <i>w</i>LEDs, innovative red-emitting phosphors with sufficient luminance and thermal stability are required. Herein, a Eu³⁺-incorporated Ba₂CaB₂Si₄O₁₄ (BCBS) phosphor, exhibiting relatively low efficiency, poor thermal stability, and red line peak photoluminescence (PL) at 614 nm, is preliminarily obtained as a result of Eu³⁺ 4f–4f transitions. The Rietveld refinements and density functional theory (DFT) calculations indicate that Eu³⁺ is energetically favored in Ca²⁺ sites. To overcome the above issues of BCBS: Eu³⁺, heterovalent Dy³⁺ is codoped into the phosphor to simultaneously realize: (i) ultrahigh thermal stability of red PL based on structure tailoring and trap regulation associated with both <i>Dy</i>(<i>Eu</i>)_Ca^• and <i>V</i>_<i>O</i>^″ defects. For comparison, by tridoping Na⁺ at the expense of <i>Dy</i>(<i>Eu</i>)_Ca^• via Dy(Eu)³⁺ + Na⁺ → 2Ca²⁺, the red PL performance is becoming very bad and even worse than that of BCBS: Eu³⁺, indicating that <i>Dy</i>(<i>Eu</i>)_Ca^• plays a major role, though the effect of <i>V</i>_<i>O</i>^″ cannot be completely ruled out, (ii) energy transfer (ET) from Dy to Eu for enhancing PL efficiency/intensity, and (iii) color-tunable PL, including “warm” white light, by combination of both autologous “cool” white PL from Dy and red emission from Eu. The assembled phosphor-converted white light-emitting diode (pc-<i>w</i>LED), adopting single-phase BCBS: Dy³⁺/Eu³⁺ with n near UV (<i>n</i>UV) LED chip via a remote “capping” packaging strategy, is a promising candidate to be applied as a white-emitting phosphor in <i>w</i>LEDs. Meanwhile, due to a strong mutual relationship between the intensity ratios of PL bands from magnetic/electric dipole transitions (EDT/MDT) for either Dy (Y/B) or Eu (R/O) and the crystal field environment, the obviously visual PL color change under distinct pressures in a wide range of pressure fluctuations indicates that the phosphor could also be used as a potentially optical pressure sensor with high sensitivity.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3800–3812 3800–3812"},"PeriodicalIF":3.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying Structure and Texture of Metal–Organic Framework Cu2(bdc)2(dabco) Thin Films by Combining X-ray Diffraction and Quantum Mechanical Modeling","authors":"Mario Fratschko,&nbsp;Nina Strasser,&nbsp;Narges Taghizade,&nbsp;Mercedes Linares-Moreau,&nbsp;Jan C. Fischer,&nbsp;Tonghan Zhao,&nbsp;Ian A. Howard,&nbsp;Paolo Falcaro,&nbsp;Egbert Zojer* and Roland Resel*,&nbsp;","doi":"10.1021/acs.cgd.4c0143310.1021/acs.cgd.4c01433","DOIUrl":"https://doi.org/10.1021/acs.cgd.4c01433https://doi.org/10.1021/acs.cgd.4c01433","url":null,"abstract":"<p >This study describes a strategy for unambiguously determining metal–organic framework (MOF) thin film structures, which is demonstrated for a pillar-layer MOF consisting of Cu paddlewheel nodes connected by benzene-1,4-dicarboxylate (bdc) linkers and 1,4-diazabicyclo[2.2.2]octane (dabco) pillars. An initial structural model is derived by isostructural replacement from the material’s Zn²⁺ analogue. This is followed by a structure optimization using density functional theory. The model is supported by comparing calculated and measured diffraction patterns and infrared spectra for two differently grown thin films. Key to verifying the structure and identifying the thin film texture are grazing incidence X-ray diffraction (GIXD) experiments with rotating samples. These probe the majority of reciprocal space and thus also allow a straightforward generation of pole figures for various diffraction peaks. Two types of films are prepared either by layer-by-layer deposition or by ceramic-to-MOF conversion. Both share the same phase but display clearly different textures: a uniplanar texture in the case of the layer-by-layer grown film and a distorted axial texture with an epitaxial alignment between MOF and Cu(OH)₂ crystallites for the ceramic-to-MOF-converted film. The variations in the texture follow from differences in the substrate surfaces. Our findings highlight the potential of performing GIXD experiments on rotating samples (augmented by theoretical modeling) to (i) determine the texture of MOF thin films and (ii) to solve MOF crystal structures from thin film data even for strongly varying textures.</p><p >Two different types of thin films of the metal−organic framework Cu₂(bdc)₂(dabco) are prepared and investigated by grazing incidence X-ray diffraction with rotating samples. Despite their fairly different textures, both types of film grow in the same phase. The crystal structure is solved theoretically by isomorphous replacement using the Zn analogue, a 3D porous structure is concluded for Cu₂(bdc)₂(dabco).</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3665–3679 3665–3679"},"PeriodicalIF":3.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.cgd.4c01433","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Threading Screw Dislocation-Initiated Step-Flow Growth of 3C-SiC on 4H-SiC","authors":"Rui Cao,&nbsp;Ziyang Cheng,&nbsp;Xiangxiang Zhao,&nbsp;Can Cui*,&nbsp;Lingbo Xu,&nbsp;Xiaodong Pi*,&nbsp;Deren Yang and Rong Wang*,&nbsp;","doi":"10.1021/acs.cgd.5c0005710.1021/acs.cgd.5c00057","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00057https://doi.org/10.1021/acs.cgd.5c00057","url":null,"abstract":"<p >Epitaxial growth of 3C silicon carbide (3C-SiC) layers holds high expectations to tackle the electron mobility challenges of high-power devices based on 4H-SiC. In this work, high-quality polycrystalline 3C-SiC layers are deposited on 4H-SiC substrates by the threading screw dislocation (TSD)-initiated step-flow growth. By optimizing the H₂ etching before epitaxy, regular steps are first created on the surface of 4H-SiC substrates to facilitate the step-flow growth of 3C-SiC. The deposition of 3C-SiC is initiated by TSDs in the center of the substrate. Single-TSD and double-TSD initiated step-flow growth are found under the deposition pressures of 100 and 200 mbar, respectively. The step-flow growth mode deteriorates from the center to the edge of 3C-SiC on 4H-SiC wafers because the lowering temperature slows down the diffusion of reactive species in the terrace, which aggravates the island growth. The 4H-SiC buffer layer is then deposited on the surface of the 4H-SiC substrate to stabilize the step-flow growth and improve the crystalline quality of 3C-SiC. We find that the insertion of the 4H-SiC buffer layer creates regularly arranged surface steps throughout the wafer, which promotes the wafer-scale step-flow deposition of 3C-SiC. The resulting 3C-SiC layer exhibits large flat mesas, with an average size of mesa being 170 × 170 μm². The large mesa significantly reduces the density of grain boundaries and improves the electron mobility of polycrystalline 3C-SiC. The electron mobility of the polycrystalline 3C-SiC in this work is comparable to that of single-crystalline 3C-SiC, which opens up a pathway for expanding the application of 4H-SiC in high-performance metal-oxide-semiconductor field-effect transistors and high-frequency electronics.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3707–3714 3707–3714"},"PeriodicalIF":3.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benzothiadiazole Tetracarboxylate-Based HoIII Metal–Organic Frameworks with Reversible Single-Crystal-to-Single-Crystal Transformations, Good Stabilities, and Fluorescence Sensing for Amino Acids in Aqueous Solutions","authors":"Zi-Yan Chen,&nbsp;Jin-Jin Wang,&nbsp;Chen Cao*,&nbsp;Teng-Fei Zheng,&nbsp;Yan Peng,&nbsp;He-Rui Wen and Sui-Jun Liu*,&nbsp;","doi":"10.1021/acs.cgd.5c0013610.1021/acs.cgd.5c00136","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00136https://doi.org/10.1021/acs.cgd.5c00136","url":null,"abstract":"<p >The structures, stabilities, and fluorescence sensing properties of rare earth metal–organic frameworks (MOFs) can be regulated by reversible single-crystal-to-single-crystal (SCSC) transformations, which attract much attention from chemical researchers. In this work, a novel dinuclear-based three-dimensional Ho^III MOF with the formula [Ho₄(BTDI)₃(DMF)₄]_<i>n</i> (<b>JXUST-51</b>) (H₄BTDI = 5,5′-(benzothiadiazole-4,7-diyl)diisophthalic acid, DMF = <i>N</i>,<i>N</i>-dimethylformamide) has been successfully prepared with a benzothiadiazole tetracarboxylate ligand and fully characterized. Very interestingly, the reversible SCSC transformations between <b>JXUST-51</b> and {[Ho₄(BTDI)₃(H₂O)₄]_<i>n</i>·4H₂O·solvents}_<i>n</i> (<b>JXUST-51a</b>) can be induced by the temperature and solvent. Both <b>JXUST-51</b> and <b>JXUST-51a</b> exhibit good thermal, solvent, and acid-basic stabilities in the pH range of 1–12. More importantly, the transformed crystalline sample of <b>JXUST-51a</b> remains stable after soaking in boiling water for 24 h. Remarkably, the presence of Ho^III ions and fluorescent BTDI^4– ligands leads to potential candidates as fluorescent sensors for <b>JXUST-51</b> and <b>JXUST-51a</b>. <span>l</span>-Lysine (Lys) and <span>l</span>-glutamic acid (Glu) in aqueous solutions can be detected by <b>JXUST-51</b> and <b>JXUST-51a</b> via fluorescence turn-on and turn-off effects with high selectivity and sensitivity, respectively. Moreover, <b>JXUST-51</b> and <b>JXUST-51a</b>’s amino acid fluorescence sensing mechanism may be explained by the interaction between Lys/Glu and the framework. Significantly, fluorescent composite films and test papers with <b>JXUST-51</b> have been further developed for the simple and rapid detection of amino acids in practical applications.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3742–3748 3742–3748"},"PeriodicalIF":3.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress and Light-Induced Dual Mechanical Properties of Two 1,3-Dicyanostilbene Derivative Crystals","authors":"Sayak Nag,&nbsp;Biswajit Bhattacharya,&nbsp;Franziska L. Emmerling and Soumyajit Ghosh*,&nbsp;","doi":"10.1021/acs.cgd.5c0009710.1021/acs.cgd.5c00097","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00097https://doi.org/10.1021/acs.cgd.5c00097","url":null,"abstract":"<p >Dynamic molecular crystals with multistimuli responses hold immense potential for applications as actuators and smart materials. Here, we report two new 1,3-dicyanostilbene derivative crystals (crystals <b>1</b> and <b>2</b>), which exhibit dual mechanical responses. Both crystals <b>1</b> and <b>2</b> demonstrate stress-induced mechanical flexibility and light-induced photomechanical bending upon exposure to a 375 nm UV LED. These two distinct mechanical responses are associated with different underlying phenomena and are independent of each other. Mechanical flexibility is attributed to the absence of slip planes and a criss-cross packing arrangement in an isotropic structure, while photomechanical bending is ascribed to the formation of a heterogeneous phase distribution due to Z → E photoisomerization. However, they show thermal reversibility, pointing toward a reversible E → Z back isomerization. This study demonstrates that single molecular crystals combining mechanical flexibility and photomechanical bending can be designed and fabricated for developing multistimuli responsive actuators.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3724–3734 3724–3734"},"PeriodicalIF":3.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying Structure and Texture of Metal-Organic Framework Cu₂(bdc)₂(dabco) Thin Films by Combining X‑ray Diffraction and Quantum Mechanical Modeling.","authors":"Mario Fratschko, Nina Strasser, Narges Taghizade, Mercedes Linares-Moreau, Jan C Fischer, Tonghan Zhao, Ian A Howard, Paolo Falcaro, Egbert Zojer, Roland Resel","doi":"10.1021/acs.cgd.4c01433","DOIUrl":"10.1021/acs.cgd.4c01433","url":null,"abstract":"<p><p>This study describes a strategy for unambiguously determining metal-organic framework (MOF) thin film structures, which is demonstrated for a pillar-layer MOF consisting of Cu paddlewheel nodes connected by benzene-1,4-dicarboxylate (bdc) linkers and 1,4-diazabicyclo[2.2.2]-octane (dabco) pillars. An initial structural model is derived by isostructural replacement from the material's Zn²⁺ analogue. This is followed by a structure optimization using density functional theory. The model is supported by comparing calculated and measured diffraction patterns and infrared spectra for two differently grown thin films. Key to verifying the structure and identifying the thin film texture are grazing incidence X-ray diffraction (GIXD) experiments with rotating samples. These probe the majority of reciprocal space and thus also allow a straightforward generation of pole figures for various diffraction peaks. Two types of films are prepared either by layer-by-layer deposition or by ceramic-to-MOF conversion. Both share the same phase but display clearly different textures: a uniplanar texture in the case of the layer-by-layer grown film and a distorted axial texture with an epitaxial alignment between MOF and Cu-(OH)₂ crystallites for the ceramic-to-MOF-converted film. The variations in the texture follow from differences in the substrate surfaces. Our findings highlight the potential of performing GIXD experiments on rotating samples (augmented by theoretical modeling) to (i) determine the texture of MOF thin films and (ii) to solve MOF crystal structures from thin film data even for strongly varying textures.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3665-3679"},"PeriodicalIF":3.2,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12151458/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144264760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism of Self-Assembled Cubic InGaN/GaN Quantum Well Formation in Metal-Modulated Molecular Beam Epitaxy.","authors":"Mario F Zscherp, Silas A Jentsch, Vitalii Lider, Matthew Chia, Andreas Beyer, Anja Henss, Donat J As, Kerstin Volz, Sangam Chatterjee, Jörg Schörmann","doi":"10.1021/acs.cgd.5c00202","DOIUrl":"10.1021/acs.cgd.5c00202","url":null,"abstract":"<p><p>Alternating metal-modulated molecular beam epitaxy enables the growth of both self-assembled c-InGaN/GaN quantum wells and fully alloyed c-InGaN layers. <i>In situ</i> reflection high-energy electron diffraction (RHEED) analysis coupled with <i>ex situ</i> structural characterization investigates the growth mechanism and prerequisites for the self-assembled c-InGaN quantum well formation. The data reveal that indium accumulates without incorporating into the underlying c-GaN layer during an indium deposition step. However, the accumulated indium forms c-InGaN during a subsequent GaN growth step consistent with vertical cation segregation. Furthermore, X-ray diffraction, time-of-flight secondary ion mass spectrometry depth profiles, and scanning transmission electron microscopy imaging show homogeneous and well-defined c-InGaN layers. The presented growth mechanism requires high substrate temperatures and gallium fluxes. Still, limit testing suggests that indium contents of up to 37% are feasible. This encourages the implementation of metal-modulated grown c-InGaN in red light-emitting devices. Furthermore, combining RHEED operando diagnostics and a precise understanding of the growth mechanism is vital for progressing toward automated growth of complex heterostructures.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3793-3799"},"PeriodicalIF":3.2,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12142808/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144245320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Osme Bonds in Molecular Crystals: Structural Insights, Substituent Effects, and Energetic Features","authors":"Sergi Burguera,&nbsp; and ,&nbsp;Antonio Frontera*,&nbsp;","doi":"10.1021/acs.cgd.5c0037110.1021/acs.cgd.5c00371","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00371https://doi.org/10.1021/acs.cgd.5c00371","url":null,"abstract":"<p >The metal-centered noncovalent interactions known as Osme bonds (OmBs) which involve group 8 elements have become the subject of interest because of their significance in supramolecular chemistry as well as catalysis and crystal engineering. We investigate how osmium tetroxide (OsO₄) complexes form metal-centered noncovalent OmBs bonds with anionic donors such as fluoride and chloride, while neutral donors such as amines and N-oxides also contribute to these interactions. The Cambridge Structural Database (CSD) systematic survey details how common these interactions are and describes their geometric properties. The nature of OmBs becomes clearer through density functional theory (DFT) calculations which demonstrate their partially covalent character while showing how substituent effects can modulate these properties. Binding energies show strong correlations with both molecular electrostatic potential (MEP) and Hammett’s σ_p constants indicating that electrostatic forces drive OmBs yet orbital contributions maintain importance. Our research work enhances knowledge about OmBs and their function in molecular construction and reaction processes, which expands the field of metal-based noncovalent interactions within supramolecular chemistry.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3949–3957 3949–3957"},"PeriodicalIF":3.2,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism of Self-Assembled Cubic InGaN/GaN Quantum Well Formation in Metal-Modulated Molecular Beam Epitaxy","authors":"Mario F. Zscherp,&nbsp;Silas A. Jentsch,&nbsp;Vitalii Lider,&nbsp;Matthew Chia,&nbsp;Andreas Beyer,&nbsp;Anja Henss,&nbsp;Donat J. As,&nbsp;Kerstin Volz,&nbsp;Sangam Chatterjee and Jörg Schörmann*,&nbsp;","doi":"10.1021/acs.cgd.5c0020210.1021/acs.cgd.5c00202","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00202https://doi.org/10.1021/acs.cgd.5c00202","url":null,"abstract":"<p >Alternating metal-modulated molecular beam epitaxy enables the growth of both self-assembled c-InGaN/GaN quantum wells and fully alloyed c-InGaN layers. <i>In situ</i> reflection high-energy electron diffraction (RHEED) analysis coupled with <i>ex situ</i> structural characterization investigates the growth mechanism and prerequisites for the self-assembled c-InGaN quantum well formation. The data reveal that indium accumulates without incorporating into the underlying c-GaN layer during an indium deposition step. However, the accumulated indium forms c-InGaN during a subsequent GaN growth step consistent with vertical cation segregation. Furthermore, X-ray diffraction, time-of-flight secondary ion mass spectrometry depth profiles, and scanning transmission electron microscopy imaging show homogeneous and well-defined c-InGaN layers. The presented growth mechanism requires high substrate temperatures and gallium fluxes. Still, limit testing suggests that indium contents of up to 37% are feasible. This encourages the implementation of metal-modulated grown c-InGaN in red light-emitting devices. Furthermore, combining RHEED operando diagnostics and a precise understanding of the growth mechanism is vital for progressing toward automated growth of complex heterostructures.</p><p >Cubic InGaN alloys are promising as active material for next-generation red LEDs. Metal-modulated molecular beam epitaxy enables the growth of self-assembled c-InGaN/GaN quantum wells. Combining <i>in situ</i> analysis and <i>ex situ</i> structural characterization reveals the prerequisites for the quantum well formation and monitors the growth mechanism.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3793–3799 3793–3799"},"PeriodicalIF":3.2,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.cgd.5c00202","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-Assembly of Chromium(II) Metal-Ion and Pyrazine Ligand into One-Dimensional Coordination Polymers","authors":"Dandan Lou,&nbsp;Nathan J. Yutronkie,&nbsp;Itziar Oyarzabal,&nbsp;Henri Barry,&nbsp;Aaron Mailman,&nbsp;Pierre Dechambenoit,&nbsp;Mathieu Rouzières,&nbsp;Fabrice Wilhelm,&nbsp;Andrei Rogalev,&nbsp;Corine Mathonière and Rodolphe Clérac*,&nbsp;","doi":"10.1021/acs.cgd.5c0042810.1021/acs.cgd.5c00428","DOIUrl":"https://doi.org/10.1021/acs.cgd.5c00428https://doi.org/10.1021/acs.cgd.5c00428","url":null,"abstract":"<p >The first examples of a one-dimensional (1D) coordination polymer featuring a chromium/pyrazine (pyz) repeating motif have been synthesized from Cr(OTf)₂-based precursors (OTf: triflate). In nitrile-based solvents (RCN), a fine control of the synthesis conditions allows the selective formation of both chain and ladder-like compounds: {Cr(pyz)(RCN)₂(OTf)₂}_n (<b>1</b>, R: Ph) and {Cr₂(pyz)₃(RCN)₂(OTf)₄}_n•X_n (<b>2</b>, R: Ph; <b>3</b>, R: Me, X: CH₂Cl₂; <b>4</b>, R: Me), respectively. Single-crystal X-ray diffraction experiments reveal the systematic presence of octahedral Cr(II) ions bridged by pyrazine ligands, forming the 1D coordination polymers. In <b>2–4</b>, these Cr-pyrazine chains are paired by additional bridging pyrazines resulting in ladder-like arrangements. In these structures, two triflate ions are coordinated via oxygen atoms to the Cr ions in a <i>trans</i>- or <i>cis-</i> configuration for <b>1–3</b> and <b>4</b>, respectively. In the <i>trans</i>- configuration, the coordinating oxygen atoms of the triflate ions align with the direction of the Jahn–Teller elongation observed at each metal node. In contrast, the chromium Jahn–Teller axis in <b>4</b> involves a pyrazine ligand, forming the rungs of the ladder structure and one triflate anion. The +II oxidation state of the Cr ions was further confirmed by X-ray absorption spectroscopy, which demonstrates the lack of intramolecular electron-transfer between the chromium center and the pyrazine and the stability of the Cr(II) ions under the given reaction conditions and coordination environments. Magnetic susceptibility measurements reveal the presence of weak antiferromagnetic interactions, which dominate between <i>S</i> = 2 Cr(II) spins in all compounds. Using a Heisenberg chain model for classical <i>S</i> = 2 spins, as developed by Fisher (<i>H</i> = −2<i>J</i>Σ_<i>i</i>=1^<i>n</i>S⃗_i·<i>S⃗_i</i>₊₁), the exchange interaction (<i>J</i>) through the neutral pyrazine is estimated at −3.1, −3.3, −3.4, and −2.5 K for <b>1–4</b>, respectively. Combining magnetic and calorimetric measurements at low temperatures, a long-range antiferromagnetic ordering is detected below 20 K in all four materials.</p>","PeriodicalId":34,"journal":{"name":"Crystal Growth & Design","volume":"25 11","pages":"3996–4005 3996–4005"},"PeriodicalIF":3.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144202811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}