Single Crystal Studies Research Articles

Multifunctional Lanthanide Metal-Organic Frameworks Act as Fluorescent Probes for the Detection of Cr2O72-, Fe3+, and TNP, White Light-Emitting Diodes, and Luminescence Thermometers.

Two basically isostructural lanthanide-based metal-organic frameworks (Ln-MOFs), {[Eu(dptz)(H2O)2]Cl·3H2O}n (JLNU-10-Eu, JLNU = Jilin Normal University) and {[Tb(dptz)(NO3)(H2O)]·7H2O}n (JLNU-10-Tb), have been successfully synthesized by employing 3-(3,5-dicarboxylphenyl)-5-(pyrid-2-yl)-1H-1,2,4-triazole (H2dptz) as a flexible carboxylic acid ligand through solvothermal reactions. Single-crystal structural studies on Ln-MOFs manifested that the compounds have a two-dimensional (2D) layered structure. Furthermore, fluorescence sensing experiments indicated that JLNU-10-Eu and JLNU-10-Tb had significant fluorescence quenching effects on Cr2O72-, Fe3+, and TNP. It should be noted that the KSV value of JLNU-10-Eu in sensing Fe3+ could reach 7.36 × 103, and the limit of detection (LOD) was 0.57. The luminescence quenching mechanism is discussed in detail through some relevant experiments. Additionally, a series of Ln-MOFs, JLNU-10-EuxTb1-x (x = 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.1), have been obtained by simply regulating the molar ratio of Eu3+ and Tb3+. Particularly, JLNU-10-Eu0.8Tb0.2 can achieve white light emission at an excitation wavelength of 300 nm. The CIE coordinates are (0.316, 0.332), which are very approximate to ideal white light. JLNU-10-Eu0.2Tb0.8 as a luminescence thermometer exhibits good linearity over the temperature range of 303-373 K with a high sensitivity of 4.1% K-1 at 373 K. The construction of multifunctional Ln-MOFs displays prospective applications in fluorescent probes, white light-emitting diodes, and luminescence thermometers.

Surface Photovoltage Spectroscopy of Ultrawide Bandgap Materials

Techniques of surface photovoltage (SPV) spectroscopy allow for the highly sensitive characterization of transitions in ultrawide bandgap materials without the need for contact preparation. Furthermore, SPV techniques can give access to electronic transitions at buried interfaces. Tools for continuous measurements of dc, ac (modulated), and ac (transient) SPV signals with the same perforated electrode and a charge amplifier are developed for spectral ranges from the near infrared up to the deep ultraviolet and for time domains from the ns to s…h to ranges. The analysis of modulated SPV transients is applied. The high empirical potential of SPV spectroscopy is demonstrated by studies of a diamond single crystal, a layer of β‐Ga2O3 grown by pulsed laser deposition, and an AlN layer epitaxially grown on sapphire. Defect‐related transitions are characterized over the entire bandgap for all mentioned materials. Several phonon‐assisted transitions near the bandgap of diamond are well detected. Different defect transitions dominating near the β‐Ga2O3 surface or near the β‐Ga2O3/sapphire interface are distinguished. Several defect transitions near the bandgap of AlN are observed. Uncertainties for interpretation of transition energies are discussed.

Crystal structure and absence of magnetic order in single-crystalline RuO2

RuO2was considered for a long time to be a paramagnetic metal with an ideal rutile-type structure down to low temperatures, but recent studies on single-crystals claimed evidence for antiferromagnetic order and some symmetry breaking in the crystal structure. We have grown single-crystals of RuO2by vapor transport using either O2or TeCl4as transport medium. These crystals exhibit metallic behavior following aT2low-temperature relation and a small paramagnetic susceptibility that can be attributed to Pauli paramagnetism. Neither the conductance nor the susceptibility measurements yield any evidence for a magnetic or a structural transition between 300 K and ∼4 K. Comprehensive single-crystal diffraction studies with neutron and x-ray radiation reveal the rutile structure to persist until 2 K in our crystals, and show nearly perfect stoichiometry. Previous observations of symmetry forbidden reflections can be attributed to multiple diffraction. Polarized single-crystal neutron diffraction experiments at 1.6 K exclude the proposed antiferromagnetic structures with ordered moments larger than 0.01 Bohr magnetons.

Synthesis, single crystal investigations, DFT studies, biological activities, DNA cytotoxicity and molecular docking studies of copper(II) complex derived from the new o-vanillin Schiff base ligand

A novel Schiff base derivative, (E)-N’-(2-hydroxy-3-methoxybenzylidene)-2-phenylacetohydrazide (HMPH, H2L), and its Cu(II) complex were synthesized through the direct condensation of o-vanillin with phenylacetichydrazide in ethanol under reflux conditions. The synthesized ligand was identified usingelemental analysis, Fourier transform infrared (FTIR) and ultraviolet–visible (UV–Vis.) spectroscopy. The structures of HMPH (C16H16N2O3)2 and its Cu(II) complex [Cu(L)(H2O)]·H2O (C16H16N2CuO4·H2O) were analysed by single crystal X-ray diffraction technique. The X-ray diffraction results showed that HMPH crystallised in an orthorhombic Pca21 space group with a Z value of 8, while [Cu(L)(H2O)]·H2O crystallised in a monoclinic C 2/c space group with the same z value. The Cu(II) ion is coordinated to the acetohydrazide ligands via hydrazone nitrogen, aceto oxygen (N(2) and O(1)) and hydroxyl O(2) atoms. In addition to the single crystal structures of HMPH and [Cu(L)(H2O)]·H2O, the optimised molecular structures, molecular electrostatic potential meps, molecular orbital energy values, and interactions between DNA bases and molecular structures are determined by DFT/B3LYP/6-311G(d, p) for HMPH and DFT/B3LYP/LanL2DZ for [Cu(L)(H2O)]·H2O. The copper complex was found to be more potent than the organic ligand in terms of antimicrobial activity, with a strong anti-biofilm effect even at low MIC values. The cytotoxicity of the synthesized compounds was investigated on MDA-MB-231 cell lines. The [Cu(L)(H2O)]·H2O complex was found to be more lethal than the HMPH ligand. Furthermore, molecular docking studies of HMPH and [Cu(L)(H2O)]·H2O with P. aeruginosa ATCC27853 (PDB ID: 6P8U) were presented to explain the observed antibacterial activity and the mechanism-of-action.

Symmetrical Bis-Hydrazone Ligand-Based Binuclear Oxido/Dioxido-Vanadium(IV/V) Complexes: Synthesis, Reactivity, and Catalytic Applications for the Synthesis of Biologically Potent 2-Phenylquinazolin-4-(3H)-ones.

Symmetrical bis(hydrazone)-based ligands, H4dar(bhz)2 (I), H4dar(fah)2 (II), H4dar(nah)2 (III), and H4dar(inh)2 (IV) obtained from 4,6-diacetylresorcinol (H2dar) and different hydrazides [benzoylhydrazide (Hbhz), isonicotinoylhydrazide (Hinh), nicotinoylhydrazide (Hnah), and 2-furoylhydrazide (Hfah)], were used to prepare potassium salts of binuclear cis-[VVO2]+ complexes, {K(H2O)2}2[(VVO2)2dar(bhz)2] (1), {K(H2O)2}2[(VVO2)2dar(fah)2] (2), {K(H2O)2}2[(VVO2)2dar(nah)2] (3), and {K(H2O)2}2[(VVO2)2dar(inh)2] (4), and binuclear [VIVO]2+ complexes, [{VIVO(MeOH)}2dar(bhz)2] (5), [{VIVO(MeOH)}2dar(fah)2] (6), [{VIVO(MeOH)}2dar(nah)2] (7), and [{VIVO(MeOH)}2dar(inh)2] (8). In the presence of warm MeOH/DMSO (4:1), 3 changed to {K(H2O)2}[(VVO2)2Hdar(nah)2]·DMSO (3a·DMSO). Single crystal XRD studies of 1 and 3a confirm a binuclear structure along with a distorted square pyramidal geometry of each vanadium center where bis{ONO(2-)} ligands coordinate through phenolate-O, azomethine-N, and enolate-O atoms of each unit. While growing crystals of 6 in EtOH, part of it oxidizes and gives [{VVO(OEt)}2dar(fah)2] (9) along with powdery 6. Complex 9 has a distorted octahedral structure. These complexes were used as catalysts for the synthesis of biologically important 2-phenylquinazolin-4-(3H)-ones having different aryl aldehydes, and they all show excellent catalytic performance (up to 97% yield) in less reaction time and low temperature, in the presence of 70% aqueous TBHP/30% aqueous H2O2 as a greener oxidant. Generally, these complexes perform better than their mononuclear analogues. Spectroscopy, DFT studies, and isolated intermediates have helped in proposing a suitable reaction mechanism for the catalytic reaction.

Correction: Raman spectroscopy study of K-birnessite single crystals

Correction for ‘Raman spectroscopy study of K-birnessite single crystals’ by Dong Han Ha et al., J. Mater. Chem. A, 2025, 13, 617–626, https://doi.org/10.1039/D4TA06118G.

Raman spectroscopy study of K-birnessite single crystals

The alterations in the crystal structure and Raman spectra of K-birnessite single crystals when water molecules intercalate into or deintercalate from the interlayer space were subjected to an in-depth examination.

A promising role of Ba2+ ion in the enhancement of structural, optical, photoluminescence, Z-scan, etching and laser damage threshold study of C6H14N4O2H3PO4H2O single crystals: Implications on photonics device applications

A promising role of Ba2+ ion in the enhancement of structural, optical, photoluminescence, Z-scan, etching and laser damage threshold study of C6H14N4O2H3PO4H2O single crystals: Implications on photonics device applications

Phthalazine based hydrazone as potent radical scavenger: Synthesis, spectral characterization, single crystal X-ray diffraction, DFT studies, molecular docking, ADME, antioxidant and antimicrobial activity of (E)-1-(2-substitutedbenzylidene)phthalazine derivatives

Phthalazine based hydrazone as potent radical scavenger: Synthesis, spectral characterization, single crystal X-ray diffraction, DFT studies, molecular docking, ADME, antioxidant and antimicrobial activity of (E)-1-(2-substitutedbenzylidene)phthalazine derivatives

Biphenyl based photo luminescent sensor for real time hydrazine detection: Design, synthesis, DFT and single crystal XRD studies

Biphenyl based photo luminescent sensor for real time hydrazine detection: Design, synthesis, DFT and single crystal XRD studies

Coordination compounds of diethyl (5-ethyl-2-hydroxyphenyl)phosphonate with lithium, sodium and potassium. Synthesis, single-crystal X-ray diffraction analysis and FTIR spectroscopic study

Coordination compounds of diethyl (5-ethyl-2-hydroxyphenyl)phosphonate with lithium, sodium and potassium. Synthesis, single-crystal X-ray diffraction analysis and FTIR spectroscopic study

Evidence of high-temperature magnetic spiral in YBaCuFeO5 single-crystal by spherical neutron polarimetry

The low ordering temperature of most non-collinear spiral magnets critically limits their implementation in devices. The layered perovskites RBaCuFeO5 are a rare case of frustrated oxide family that has raised great expectations as promising high-temperature spiral magnets and spin-driven multiferroic candidates. Though a non-conventional mechanism of ‘spiral order by disorder’ could account for the extraordinary thermal stability of their presumed spiral order, such order was alleged on the basis of non-conclusive neutron data on powder samples. Thus far, it has not yet received support from single-crystal studies able to lift the ambiguities of powder data. Here, a YBaCuFeO5 crystal has been grown with enough Cu/Fe disorder to stabilize the incommensurate magnetic phase up to TS ≈ 200 K. Utilizing spherical neutron polarimetry and single-crystal neutron diffraction, we unveil the features of its magnetic structures, demonstrating the non-collinear chiral nature of the magnetic domains in the singular incommensurate phase. It is thus finally proved that such phase is spiral in our crystal, and therefore also in those compositions of this perovskite family where TS values well above room temperature have been reported. Yet, this study also illustrates critical features of relevance to the search for high-temperature magnetoelectric response induced by the spiral phase.

Diiridium(III) Complexes with Fluorenylpyridyl Cyclometalating and μ2‐Oxamidato Bridging Ligands and their High Efficiency Phosphorescent Solution‐Processed OLEDs

Three neutral diiridium(III) complexes with 2‐fluorenylpyridyl (flpy) or 5‐fluoro‐2‐fluorenylpyridyl (flpyF) as C^N cyclometalating ligands and a μ2‐oxamidato bridge have been synthesized. NMR spectroscopy shows that the complexes are inseparable mixtures of diastereomers (rac, DD/LL and meso, DL) with bridges in anti and syn configurations. Each isomer was determined using 19F NMR data on the flpyF complex. Single crystal diffraction studies of two complexes revealed meso diastereomers with anti configuration of the bis‐(t‐butylphenyl)oxamidato bridge but an uncertain configuration of the unsubstituted μ2‐oxamidato bridge. The complexes are highly emissive (ΦPL 57‐82% in solution) with excited state lifetimes of tp ca. 40 ms. The vibronic emissions with maxima at 553‐561 nm and at 587‐595 nm in solution are attributed to mixed metal‐ligand to ligand charge transfer (3MLLCT). Density functional theory (DFT) and time dependent‐DFT (TD‐DFT) calculations establish the involvement of the fluorenyl groups and the vibronic structures in the emissions. The bridge mediates intramolecular interactions between iridium centers based on electrochemical measurements Phosphorescent organic light‐emitting diodes (PhOLEDs) using these complexes as the emissive dopants with a solution‐processed active layer have bright greenish‐yellow emission with lmaxEL ca. 560 nm, luminous efficiency up to 26 cd/A and high external quantum efficiency (maximum hext ca. 20%).

Systematic Investigations of the Solid Solution Zr(V1-xAlx)2 Adopting the Laves Phase Structures.

Laves phases are an interesting field of research when it comes to structural chemistry and physical properties. Investigations of the ternary system Zr-V-Al showed, in contrast to the system Hf-V-Al, that no superstructures can be observed within the solid solution Zr(V1-xAlx)2. High values of x form aluminum rich phases that adopt the hexagonal MgZn2 type structure while low values of x lead to vanadium rich phases that adopt the cubic MgCu2 type. All samples were investigated by powder X-ray diffraction experiments. Single crystal studies indicated that no superstructure formation is present in the investigated samples. 27Al MAS NMR investigations confirmed these findings. For ZrAl2, quantum-chemical calculations helped with the analysis of the 27Al NMR spectrum of the binary endmember of the solid solution. Some of the prepared samples were investigated with respect to their magnetic properties. The investigated compounds show Pauli-paramagnetism, in Zr(V0.875Al0.125)2 in addition superconductivity with a critical temperature of TC = 4.17(1) K was observed. Investigations of compositions that do not belong to the Laves phase regime clearly indicate that the MgZn2 type structure is still the dominant phase. Regardless of the starting composition chosen, the hexagonal Laves phase was mostly present.

Synthesis of Single-Crystal Two-Dimensional Covalent Organic Frameworks and Uncovering Their Hidden Structural Features by Three-Dimensional Electron Diffraction.

Two-dimensional covalent organic frameworks (2D COFs) are formed by the polycondensation of geometrically specific monomers to grow covalently connected 2D polygonal polymers over the a-b plane and supramolecular polymerization and/or crystallization of 2D sheets along the c direction to constitute layer architectures. Despite various efforts, the synthesis of single-crystal 2D COFs remains a challenging goal. Here, we report the synthesis of single-crystal 2D COFs, by taking the representative imine-linked TPB-DMTP-COF as an example, to reveal the key synthetic parameters that control the crystallization of 2D COFs. We systematically tune the synthetic conditions including the glassware setup, the degas method, the solvent, the temperature, the modulator, and the reaction time and observed that all these parameters greatly affect the polymerization and crystallization processes, controlling the crystal quality. We found that a homogeneous system with all components dissolved and the presence of a suitable modulator at a temperature of 50-70 °C allows the growth of TPB-DMTP-COF single crystals as isolated individual rods, with tunable diameters of 200 nm to 3 μm and a length of 1-20 μm. The single-crystal structure was characterized by three-dimensional electron diffraction (3DED), which revealed two conformations of trans and cis for the linker in the 2D polymer sheets, which stack in an antiparallel mode to shape the frameworks with double-sized unit cells. These results uncover these hidden structural features which have been overlooked in polycrystalline and single-crystal studies and provide new insights into the synthesis of high-quality single crystals of 2D COFs.

Ambidentate behavior of oximate in VO(OMe)2+ and VO2 + complexes with biacetylmonoxime 4-R-benzoylhydrazones: syntheses, structures, and properties

Reactions of bis(acetylacetonato)oxovanadium(IV), [VO(acac)2], with biacetylmonoxime 4-R-benzoylhydrazones (H2L1 (R = Me) and H2L2 (R = OMe), where 2Hs represent the dissociable oxime and amide protons) in 1:1 mole ratio in methanol result in complexes [VO(OMe)(MeOH)(L1)] (1) and [VO(μ-OMe)(L2)]2 (2). When reactions were performed in the presence of two molar equivalents of KOH, K[VO2(L1)]·MeOH (3) and K[VO2(L2)]·2MeOH (4) were obtained. The complexes have been characterized using elemental analysis and mass spectrometry along with magnetic, solution electrical conductivity, thermogravimetric, various spectroscopic (IR, UV-Vis, and 1H NMR), and cyclic voltammetric measurements. The molecular structures of H2L1 and complexes 1-4 were determined by single-crystal X-ray crystallographic studies. In both 1 and the dimethoxo bridged centrosymmetric 2, the metal centers are in distorted octahedral NO5 environment, where (L1/2)2− meridionally coordinate the respective metal centers through the amidate-O, imine-N, and oximate-O and form fused 5,6-membered chelate rings. In 3 and 4, the metal centers have distorted trigonal bipyramidal N2O3 coordination spheres, where the fused 5,5-membered chelate rings forming amidate-O, imine-N, and oximate-N donors (L1/2)2− occupy the axial-equatorial-axial positions. The physical properties of all four complexes are consistent with their molecular formulas and structures.

Nanoindentation mechanical studies of bulk AlN single crystals with different orientations

Abstract This study utilized nanoindentation to perform nano-mechanical tests on freestanding aluminum nitride (AlN) single crystal substrates with (0002), (10–10), and (11–20) orientations prepared by the physical vapor transport (PVT) method with varying indentation depths. The results indicate that the c-plane exhibits greater hardness and smaller Young’s modulus compared to other orientations. Moreover, the mechanical properties of AlN with different orientations demonstrate consistency with the indentation size effect, showing a decrease in both hardness and Young’s modulus with increasing indentation depth. Surface morphology of the indentations was observed using SEM, revealing that at high loads, no obvious cracks were found in the c-plane indentation except for slight deformation, while the m-plane and a-plane indentations produced cracks extending along the a- and m-directions, respectively. Cathodoluminescence (CL) results demonstrated that dislocations and structural defects generated by the indentation produced the luminescence quenching. Notably, the inverted triangular dislocation slip region was clearly observed in the panchromatic CL images of c-plane indentation. The anisotropy of the phonon peaks at different crystal planes and the nature of the local stress at the indentation were further analyzed using Raman spectroscopy.

Nanoindentation study of PbMoO4 single crystals: mechanical properties and implications for applications

Abstract Nanomechanical properties of lead molybdate (PbMoO4) single crystal were investigated using nanoindentation measurements. The force-dependent Young’s modulus and hardness of PbMoO4 along the [100] direction was determined using the Oliver–Pharr method. As the applied force increased, hardness and young modulus values decreased. This behavior was referred to the indentation size effect (ISE). The force-dependent plots were analyzed using proportional specimen resistance model and true hardness value was determined as 1.84 GPa. As a result of increasing the applied force from 5 to 100 mN, the Young modulus decreased from 81.7 to 60.2 GPa. The dependencies of plastic and elastic deformation components were also reported in the present study. It was seen that plastic deformation is the dominant component. The findings suggest that PbMoO4 is relatively soft material and can be considered as a promising material for mechanical and optoelectronics applications that require revealed hardness and Young’s modulus values.

Correction to: Structural, mechanical and antimicrobial studies of GZnA single crystal via slow solvent evaporation process

Correction to: Structural, mechanical and antimicrobial studies of GZnA single crystal via slow solvent evaporation process

Synthesis, characterization, X-ray structure, and DFT calculations of Zn complex encompassing HLN2O ligand: Relevance in cytotoxicity and antifungal photodynamic therapy.

This article presents the synthesis, characterization, and X-ray crystallographic features of one new Zn complex derived from a Salen-type tridentate ligand (HLN2O). A single-crystal diffraction study determined the complex crystal structure, which confirms that it crystallizes in the orthorhombic space group P212121. The single-crystal structure is constructed using the unique mononuclear component [ZnLN2°] and supramolecular CH∙∙∙π type interaction, resulting in a 1D structure. The IR, HRMS, and NMR study also support the complex structure. The Zn metal centre has a distorted square pyramidal geometry with τ value of 0.49. The Hirshfeld surfaces and 2D fingerprint confirm predominant H…H (77.9 %) interactions, with minor H…O, H…C, and H…N (5.0 %, 4.9 %, and 0.2 %). DFT calculations employed the B3LYP-D3/Lanl2DZ class of theory. FMO/MEP explains the complex reactivity perspective, while IP (4.71 eV) and low EA (1.11 eV) suit biological applications. The bonding gateway was analysed using NBO/QTAIM-NCI and ELF-LOL plots. Cytotoxicity was assessed using the Trypan blue exclusion method and tested against the DLA cell line, showing effectiveness against the DLA cell and suggesting complex potential as an anticancer agent. Antifungal photodynamic therapy (APDT) explored that ligand and Zn complex have significant activity against C. albicans. Finally, molecular docking simulations substantiate the experimental findings.