Single Crystal Structure Research Articles

Ion sensors based on organic semiconductors acting as quasi-reference electrodes

Thin-film devices that transduce the chemical activity of ions into electronic signals are essential components in various applications, including healthcare diagnostics and environmental monitoring. Combinations of organic semiconductors (OSCs) and ion-selective materials have been explored for developing solution-processable ion sensors. However, the necessity of reference electrodes (REs) and operational stability in ion-permeable OSCs have posed questions regarding whether reliable measurements with thin-film components are attainable with OSCs. Herein, we report electric double-layer transistors (EDLTs) with OSCs in single-crystal forms for ion sensing. Our EDLTs demonstrated high operational stability, with a one-to-one relationship between the source electrode potential and device resistance, and served as quasi-REs (qRE). When our EDLT is served as qRE, its drift was as small as 0.5 mV/h and comparable to that of commonly employed REs. In our system, the semiconductor-electrolyte interface is self-passivated by the alkyl chains of OSCs in single-crystal structures, with the two-dimensional transport layer appearing unaltered upon gating. EDLT arrays with ion-selective and nonselective liquid junctions enable ion concentration sensing without a conventional RE. These findings provide opportunities to develop thin-film devices based on OSCs for easy integration and reliable measurements.

Monitoring the Dissolution Behavior of Novel Pharmaceutical Cocrystals Consisting of Antimalarial Drug Artemisinin with Probe-Type Low-Frequency Raman Spectrometer

Artemisinin (ART) is a most promising antimalarial agent. However, its low aqueous solubility limits its oral absorption, resulting in low bioavailability. In this study, we have successfully discovered a novel cocrystal with 2-methyl resorcinol (ART-2MRE) providing improved solubility compared with a previously reported cocrystal with resorcinol (ART-RES). Single crystal X-ray structure analysis revealed that the ART-2MRE cocrystal was composed of ART and 2MRE in a molar ratio of 2 : 1. Though the ART-2MRE and ART-RES cocrystals were found to have similarities in their crystal structures, with one layer of a cocrystal former and two layers of ART arranged in alternating rows, the ART-2MRE cocrystal showed higher dissolution rate than ART-RES cocrystal. In situ real-time low-frequency (LF) Raman monitoring and powder X-ray diffraction (PXRD) measurements of the crystals during the dissolution test proved useful to investigate the dissolution behavior of the cocrystals. Low-frequency Raman monitoring revealed that as dissolution progressed, there was a continuous shift from the peak unique to the ART-2MRE cocrystal to the peak unique to the ART stable form. Similar observations were obtained in PXRD measurements as well. Furthermore, experiments were conducted by adding a polymer to the dissolution test solution to investigate the dissolution behavior under supersaturation, indicating the possibility of differences in the dissolution behavior between the ART-2MRE cocrystal and ART-RES cocrystal. Understanding the dissolution behavior from cocrystals is essential in developing cocrystals.

A 1,4-benzoquinone with counteracting inductive donor and acceptor substituents

Investigation of a published route to produce 3,5-di- tert-butylphenol, starting from commercial 3,5-di- tert-butylbenzoic acid via 3,5-di- tert-butylanlinium hydrogen sulfate, unexpectedly yielded 2,6-dintitro-3,5-di- tert-butylphenol. Attempts to increase the yield of the latter resulted, instead, in the previously unreported 2,6-dinitro-3,5-di- tert-butylcyclohexa-2,5-dien-1,4-dione. Single-crystal X-ray diffraction structures are reported for the anilinium salt, the nitrated phenol, and the quinone. Voltammetry of the quinone shows two chemically reversible reductions in anhydrous solution and the radical anion produced from the first reduction step has been characterized by electron paramagnetic resonance spectroscopy. This compound fits well to the middle range of electron-poor quinones, indicating that the inductive effects of the tert-butyl and nitro groups counteract each other. This conclusion is also supported by the infrared spectroscopic data where the ν(C=O) and ν(C=C) bands are of very similar energy to those of 2,3,5,6-tetrachloro-1,4-benzoquinone.

Growth of anthracene microcrystals by the micro-space sublimation method and their photophysical properties

Anthracene and its derivatives are widely utilized in optoelectronic devices due to their unique properties. Generally, single-crystal structures can avoid non-radiative recombination, enhance carrier mobility, and ultimately improve device performance. In this work, anthracene microcrystals were prepared using the micro-space sublimation method. Through real-time in-situ observation, the crystallization dynamics of anthracene molecules were revealed. Unlike traditional vacuum evaporation deposition technique, the close proximity of the substrate to the source facilitates the self-assembly of anthracene molecules into an ordered crystal structure. Six peaks can be observed in the photoluminescence spectrum, corresponding to various lowest excited state decay processes. The fluorescence intensity at the peak of 423 nm decreases significantly with increasing temperature. The reason for this is the relatively high exciton binding energy, which makes excitons more stable and easier to form. The lattice vibrations induced by increased temperature were found to affect the transport and separation of excitons. Time-resolved fluorescence spectroscopy imaging revealed that a relatively uniform distribution of fluorescence lifetimes in the anthracene microcrystals, indicating high crystallization quality. This work provides valuable insights for controlling the morphology and investigating the photophysical properties of organic semiconductors.

Facile Synthesis of a Layered Bismuth-Based MOF With Superhydrophobic-Oleophilic Property and High Oil-Water Separation Performance.

Metal organic frameworks (MOFs) are a class of potential superhydrophobic-oleophilic materials. The organic ligands in superhydrophobic MOFs usually contain long alkyl chains, fluorine groups or aromatic rings with large π conjugation, the preparation of which suffers from high cost, complex operation and so on. In addition, the topological structure of MOFs plays an important role in the hydrophobicity, which may be ignored previously. Here we report a superhydrophobic-oleophilic MOF (BiPPA2) obtained by a facile and fast method, which not only displays a large water contact angle of up to 163° and a small sliding angle of nearly equal to 0°, but also exhibits high sorption capacity for multiple oils and organic solvents, well reusability and high oil retention. In addition, BiPPA2 is stable in a wide pH range (0.5-11.0). Finally, the single crystal structure of BiPPA2 is resolved to reveal the intrinsic reason for the super-hydrophobicity. This work may inspire the further design of pristine superhydrophobic MOFs based on a simple method, which enriches the family of superhydrophobic MOFs and has great significance for practical applications.

Investigation on the microstructure, mechanical properties and chlorine resistance of fine aluminum alloy wires

Wire bonding is a fundamental and mature technology in semiconductor packaging process, primarily using materials such as gold, silver, aluminum, and copper for the wires. To address application limitations of aluminum wires, such as low electromigration resistance and limited ductility, techniques including to enhance alloying (with Zn and Si), heat treatment, and surface treatment are employed to enhance the performance of aluminum alloy wires and broaden their application value. This study selects Al-3Zn-0.3Si (AZS303) and Al-7Zn-0.3Si (AZS703), with AZS303 undergoing gold plating to produce AC-AZS303 wires. Various high-temperature heat treatments are applied, verifying that under 400 °C conditions, the AZS series aluminum alloy wires exhibit grain growth and form single-crystal equiaxed grain structures, resulting in stable mechanical properties and excellent electrical performance. Additionally, the AC-AZS303 wires optimize resistance values through gold layer diffusion induced by the electrothermal effect.Chlorine experiments indicates that the gold plating on AC-AZS303 can't enhance the aluminum wire's resistance to chlorine corrosion. However, the alloying effect of zine and silicon elements imparts excellent chlorine corrosion resistance to the Al-Zn-Si wires. This study of bonding properties examines the bond strength and observes the bonded area of Al-Zn-Si wires after bonding. It is noted that the H400-AZS303 wire exhibits the best bond strength and bonding area, demonstrating good bonding with the substrate.

Comprehensive analysis of 2,5-dimethyl-1-(naphthalen-1-yl)-1H-pyrrole: X-ray crystal structure, spectral, computational, molecular properties, docking studies, molecular dynamics, and MMPBSA

This study examines the features of 2,5-dimethyl-1-(naphthalen-1-yl)-1H-pyrrole (DN1HP) in terms of its structure, vibrations, electronic transition properties, biological activity, and thermodynamic characteristics. X-ray single crystal structure solved and analysed. With the use of spectroscopic methods like FT-IR and UV–vis, the compound has been described. These experimental findings were contrasted with information derived from DFT (B3LYP) computations with the basis set 6–311++G(d,p). Vibrational allocations and Potential energy distribution(PED) were computed after optimizing the DN1PH compound's shape. The outcome of every experiment matched the values predicted by theory. To further investigate the reactivity, stability and biological activity of the titular molecule, calculations were made for the electrophilicity index (3.053), energy gap (3.789 eV), EH (−5.2962 eV), and EL (−1.5069 eV). To determine the compound's electrophilic and nucleophilic locations, a Molecular electrostatic potential (MEP) diagram was established. Molecular docking experiments have demonstrated the potential of the molecule in question as an anti-HIV medication. The binding energies of the drug to the proteins 3MLU, 3QEG, 5DHZ, and 3MLY are −5.86, −5.04, −5.01 and −4.97 kcal/mol, respectively. To further investigate the relationship and reliability of the protein (3MLU) with DN1HP, molecular dynamics (MD) simulators were utilized

On-site visual sensing of antibiotics in food by new fluorescent lanthanide metal–organic frameworks

In recent years, foods that contaminated by the antibiotics is a serious threat to human health, so, the on-site visual detection of antibiotics in food is crucial. In this work, two new two-dimensional lanthanide metal–organic frameworks (2D LnMOFs) are synthesized by mild hydrothermal method and detailly characterized by single crystal structure analysis, photophysics, thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), FT-IR spectra. Results show the two LnMOFs has high thermo-stability, strong acid and alkaline resistance. Further studies reveal that TbMOF is a highly sensitive and selective fluorescent probe for the antibiotics of enrofloxacin (Enr) and ciprofloxacin (Cip), with a very short response time of 15 s. The limits of detection (LODs) for Enr and Cip are very low values of 190 and 70 nM, respectively, based on the method of 3σ/K, which is lower than the national food safety standard (GB 31650–2019). In addition, portable test paper based on TbMOF is fabricated, which realized the visible and on-site detection of Enr and Cip in the real samples of egg and milk.

Single-Crystal Structure Analysis of Dicarboxamides: Impact of Heteroatoms on Hydrogen Bonding of Carboxamide Groups

This research examines how heteroatoms in a six- or five-membered pyridine, thiophene or furan ring spacer between two carboxamide groups influence the hydrogen bonding for advancements in supramolecular chemistry and drug development. The solvent-free crystal structures of 3,5-pyridinedicarboxamide (PDC), 2,5-thiophenedicarboxamide (TDC) and 2,5-furandicarboxamide (FDC-subl, crystallized by sublimation), and the monohydrate structure of FDC-solv (crystallized from methanol) are described with the hydrogen-bonding analyzed by the Etter graph-set notation. The carbon atoms of the amide groups form an angle of 121° in PDC, 151° in TDC, 137° in FDC-solv and 135° in FDC-subl with the ring centroid. Only in the structure of PDC does the heteroatom act as an H-bond acceptor as part of a C11(6) chain. In TDC and FDC, the heteroatoms do not interact with the amide -NH2 groups.

The functional moieties impact on optical, thermal, and nonlinear properties of chalcone derivatives. A comprehensive study on FT2MP

This study explains the intricate interplay between functional groups and the single crystal structure of the compound 1-(furan-2-yl)-3-(2,4,6-trimethoxyphenyl)prop-2-en-1-one (FT2MP) using Density Functional Theory (DFT) calculations. Notably, geometry optimization at B3LYP using 6-311G+(2d,p) closely aligned with experimental distances from X-ray diffraction (XRD) upon comparison. A Q-switched, frequency-doubled pulsed Nd. YAG laser (532 nm, 7 ns pulses), a 25 cm focal length lens, and a 0.001 mol/L FT2MP solution in Dimethylformamide was used to measure third-order nonlinear optical (NLO) parameters and subsequently the origin of second/third harmonic generation efficiency is discussed. The third-order nonlinear parameters of FT2MP were found to be Δɸ = 0.95, n2 = −9.605 × 10−9 cm2/W, β = 2.74 × 10−6 cm/W, and χ(3) = 5.58 × 10−7 esu. Information about the electronic structure and reactivity of the molecule is provided via the addition of Global Chemical Reactivity Descriptors (GCRD), molecular electrostatic potential (MEP) and Frontier Molecular Orbitals (FMOs) for electronic structure and reactivity insights. Hirshfeld surface analysis was used to study intermolecular interactions. This investigation indicates the potential of FT2MP for third harmonic generation, providing a comprehensive understanding of its molecular structure, reactivity, and intermolecular interactions.

Exploring the Potential of N‐Benzylidenebenzohydrazide Derivatives as Antidiabetic and Antioxidant Agents: Design, Synthesis, Spectroscopic, Crystal Structure, DFT and Molecular Docking Study

AbstractHydrazone‐type Schiff bases have been widely explored owing to their therapeutic properties. These compounds are known to have antibacterial, antifungal, anticancer, and antioxidant properties, among others. In the present study, six hydrazone‐based Schiff bases (BB1–BB6) were synthesized by the reaction between derivatives of benzaldehyde and benzo hydrazide in methanolic medium in the presence of catalytic amount of formic acid. The synthesized compounds were characterized using various spectroscopic techniques such as NMR (1H, 13C, COSY, DEPT, HSQC, HMBC, and NOESY), FTIR, UV‐Vis, elemental (CHN) analysis, and high‐resolution mass spectroscopy. In addition, single crystal structures of BB2, BB4, and BB6 were obtained. In vitro antidiabetic and antioxidant potential of the compounds was evaluated on glucosidase, amylase, NO, FRAP, and DPPH assays, respectively. In all the assays, compounds BB6, BB4, and BB2 showed higher activity than the others. To further explore the chemical reactivity properties and their mechanism of action against the tested assays, DFT and molecular docking study were performed, and the results obtained reinforce the experimental study data.

Two-dimensional-lattice-confined single-molecule-like aggregates.

Intermolecular distance largely determines the optoelectronic properties of organic matter. Conventional organic luminescent molecules are commonly used either as aggregates or as single molecules that are diluted in a foreigner matrix. They have garnered great research interest in recent decades for a variety of applications, including light-emitting diodes1,2, lasers3-5 andquantum technologies6,7, among others8-10. However, there is still a knowledge gap on how these molecules behave between the aggregation and dilution states. Here we report an unprecedented phase of molecular aggregate that forms in a two-dimensional hybrid perovskite superlattice with a near-equilibrium distance, which we refer to as a single-molecule-like aggregate (SMA). By implementing two-dimensional superlattices, the organic emitters are held in proximity, but, surprisingly, remain electronically isolated, thereby resulting in a near-unity photoluminescence quantum yield, akin to that of single molecules. Moreover, the emitters within the perovskite superlattices demonstrate strong alignment and dense packing resembling aggregates, allowing for the observation of robust directional emission, substantially enhanced radiative recombination and efficient lasing. Molecular dynamics simulations together with single-crystal structure analysis emphasize the critical role of the internal rotational and vibrational degrees of freedom of the molecules in the two-dimensional lattice for creating the exclusive SMA phase. This two-dimensional superlattice unifies the paradoxical properties of single molecules and aggregates, thus offering exciting possibilities for advanced spectroscopic and photonic applications.

Upconversion Luminescence in a Photostable Ion-Paired Yb-Eu Heteronuclear Complex.

Lanthanide-based upconversion molecular complexes have potential application in diverse fields and attracted considerable research interest in recent years. However, the similar coordination reactivity of lanthanide ions has constrained the designability of target molecule with well-defined structure, and many attempts obtained statistical mixtures. Herein, an ion-paired Yb-Eu heteronuclear complex [Eu(TpPy)2][Yb(ND)4] (TpPy = tris[3-(2-pyridyl)pyrazolyl]hydroborate, ND = 3-cyano-2-methyl-1,5-naphthyridin-4-olate) was designed and synthesized. Thanks to the radius difference between Eu3+ (1.07 Å) and Yb3+ (0.98 Å) ions, the hexadentate TpPy ligand was selected to coordinate with Eu3+ and the Yb3+ with a smaller radius was chelated by bidentate ND ligand. As a result, the sites of Eu3+ and Yb3+ in the complex can be clarified by high-resolution mass spectrometry and single-crystal structure analysis. Upon the excitation of Yb3+ at 980 nm, the upconversion emission of Eu3+ was realized through a cooperative sensitization process. Furthermore, [Eu(TpPy)2][Yb(ND)4] demonstrated excellent photostability during continuous high-power density 980 nm laser irradiation, with a LT95 (the time to 95% of the initial emission intensity) of 420 minutes. This work provides the first example of a pure ion-paired Yb-Eu heteronuclear complex upconversion system and may bring insights into rational design of lanthanide-based upconversion molecular complexes.

Orbital coupling of Pt single crystal via decoration of hetero-diatomic nickel-cobalt for efficient hydrogen evolution

Loading active metals in forms of single atoms or nanocluster is considered as an effective approach for designing catalysts with high atomic utilization efficiency. However, synthesis single atoms or clusters precisely in large quantities is a challenge. In this work, the isolated diatomic sites (Ni, Co) decorated single crystal Pt cluster were synthesized as efficient catalyst for hydrogen evolution. Adjacent Ni and Co atoms optimize the electronic structure of Pt single crystal, effectively lowering the water dissociation barrier and ensuring optimal binding strength of intermediates throughout the reaction process. As results, the mass activity of 2.087 A mg−1 was achieved under 200 mA cm−2, approximately 3 times than that of Pt/C. Theoretical calculations reveal that diatomic Ni, Co decorated Pt cluster reduces the energy barrier for breaking the OH-H bond, as well as facilitating the preferential adsorption and dissociation of H*. This work provides an opportunity for regulation electronic structure of catalytic via decoration single crystal cluster with diatomic sites and provides guidance for designing high efficiency electrocatalysts for promising applications.

Modularly Precise Construction of B,N-Embedded Large-Sized Polycyclic Aromatic Hydrocarbon Nanographene.

A modular "fjord-stitching" reverse strategy has been disclosed to successfully prepare two large-sized B,N-embedded nanographenes: BN-TBTi and BN-TBTo. These two compounds both exhibit excellent stability, nonzero-bandgap and decent photoluminescence quantum yield. Single crystal structure of BN-TBTo features a large C78B2N4 π-skeleton with length and width of approximately 2.4 and 1.5 nm, respectively.

Synthesis of base-modified fluorescent furo[3,2-c]coumarin nucleosides and their photophysical studies

A small library of fluorescent furo[3,2-c]coumarin nucleoside analogues has been successfully synthesized via a one-pot condensation reaction of 3′,5′-di-O-acetyl-5-formyl-2′-deoxyuridine, alkyl isocyanides, and differently substituted 4-hydroxycoumarins in acetonitrile at 80 °C. Further, the synthesized compounds have been characterized by IR, 1H NMR, 13C NMR, 1H–1H COSY, 1H–13C HETCOR, 2D NOESY NMR experiments, HRMS measurements and single crystal X-ray structure analysis of compound 5-(2′'-N-(cyclohexyl)-amino-4′'H-furo[3,2-c]chromen-4-one-3′'-yl)-2′-deoxyuridine. The electronic structure of these modified nucleosides has been examined by Density Functional Theory (DFT). The synthesized nucleoside analogues exhibited a prominent emission spectrum, featuring a band around 500 nm (with excitation at 380 nm). Photophysical investigations revealed a noteworthy fluorescence intensity, along with excellent Stokes shift values (54–194 nm) and higher quantum yields (0.010–0.515) in comparison to other pyrimidine-based fluorescent nucleosides. The solvatochromic studies of 5-(2′'-N-(cyclohexyl)-amino-8′'‑chloro-4′'H-furo[3,2-c]chromen-4-one-3′'-yl)-2′-deoxyuridine determined the quantum yield (ΦF) to be 0.515 in DMSO (λabs = 388 nm). This emphasizes the potential utility of these modified nucleosides in probing the local structure and dynamics of nucleic acids. Moreover, the scalability of the synthesis protocol was effectively demonstrated by producing one of the compounds on a gram scale, exhibiting its practical viability for large-scale production.

Temperature-induced structure evolution in monocrystalline and polycrystalline cobalt via molecular dynamics simulations

The structure transition of metallic melt strongly depends on temperature and significantly influences the comprehensive properties. However, observing the structure change in experiments is still challenging. Here, molecular dynamics is used to study the melting process and microstructural evolution in single crystal and polycrystal cobalt (Co). The results indicate that the melting process of single crystal structure starts from 1870 K and lasts for a very short period, while the polycrystal melts from about 1760 to 1870 K. In polycrystal Co, the melting initially occurs in grain boundaries, and the melting temperature shows a positive correlation with grain size. An interesting solidification phenomenon occurs on the surface of big grains in the beginning of melting process. The coordination number increasing from 12 to about 13.4 near melting point proves the local expansion of the first coordination shell, indicating the structural evolution from long-range order to short-range order in the continuous heating process. The common neighbor sub-cluster index and Voronoi polyhedron demonstrate the short-range icosahedron structures, while these polyhedrons become polydisperse and isolated in Co liquid. The findings ignite the investigation of the liquid structure origin of crystal materials and extend the understanding of the atomic structure evolution in melting.

Dual-response signal under mechanical stimulation: Alkyl substituent effect on the fine-tuning of molecular packing

Mechanical stimulus-responsive materials are generally considered to be closely related to molecular packing in the solid state, underscoring the significance of regulating molecular packing via precise molecular design. In this study, flexible alkyl substituents were employed to adjust the molecular packing. By modifying alkyl substituents, predictable changes in the molecular packing of their derivatives were observed, resulting in adjustable ML properties. The DPA-PYZ-TB with a tert-butyl-side chain exhibited strong ML and MC stimulus response signals. The enhanced ML and MC performance can be attributed to the effective suppression of non-radiation through the helical crystal arrangement and strong intermolecular interactions. The relationship between molecular arrangement and ML/MC properties was validated through analysis of the single crystal structure and corresponding experimental results. This study offers valuable insights into the enigmatic ML process and the development of efficient luminous materials that utilize both MC and ML.

Crystal structure and biological activity studies of two different types of herbicide safeners

Two heterocyclic compounds, imidazolidine-1,3-diylbis((5-methyl-3-phenylisoxazol-4-yl)methanone) (I) and (5-methylisoxazol-3-yl)(1-oxa-4-azaspiro[4.5]decan-4-yl)methanone (II), were characterized by X-rays. Compound I was crystallized in monoclinic system, space group Cc, a= 9.81000(12) Å, b= 15.21199(16) Å, c= 14.25369(17) Å, β= 90.3862 (12)degree, Z= 4, V= 2127.02(4) Å3, F(000) = 928.0, Dc= 1.382 Mg/m3, crystal size: 0.150 x 0.130 x 0.120 mm. Compound II was crystallized in the monoclinic system, space group P21/n, a = 5.6113(5) Å, b = 11.2280(10) Å, c = 20.675(2) Å, β = 95.543(10)degree, Z = 4, V = 1296.5(2) Å3, F(000) = 536.0, Dc = 1.282 Mg/m3, crystal size: 0.130 x 0.120 X 0.110 mm. Bioactivity assays showed that both compounds have good safety activity against nicosulfuron injury to corn, comparable to the commercial safener isoxadifen-ethyl. The molecular docking model indicated that two types of herbicide safeners competed with nicosulfuron for the acetolactate synthase active site and that this is the protective mechanism of safeners.. KEYWORDS :1,3-Disubstituted imidazolidine, Aryl-substituted formyloxazolidines, Single-crystal structure, Herbicide safener activity.

Potential building blocks for porous organic materials

2,4-Difluoronitrobenzene has been reacted with a linker diamine (ethylenediamine or propylenediamine) and butylamine, in either order, to give new molecular building blocks for porous supramolecular networks. Two structures were established by X-ray single crystal structure determinations. The propylenediamine structure displays small pores, which may be due to the longer and more flexible linker in the structure.