Crystal Analysis Research Articles

Design and synthesis of heteroleptic Ni(II) dipyrrin complexes for electrochemical proton reduction reactions: Cyclic voltammetric and theoretical studies

The effect of nuclearity on electrochemical hydrogen generation using new heteroleptic Ni(II) complexes containing redox-active dipyrrin and dithiocarbamate ligands has been described. Complexes 1–2 have been meticulously characterized by spectroscopic studies (ESI-MS, IR, 1H, 13C NMR, UV–vis) and their structures unambiguously confirmed by X-ray single crystal analyses. Electrocatalytic properties of the complexes toward hydrogen evolution reaction have been investigated by cyclic voltammetric studies in an organic medium in the presence of acetic acid as a weak proton source. Notably, complexes 1 and 2 produce H2 via doubly reduced Ni(II) species i.e. Ni(0) in the presence of acetic acid. Further, these complexes exhibited significant electrocatalytic activity (TOF: 264 (1) and 650 s−1 (2). Controlled potential electrolysis established a minimum Faradaic efficiency of 92 (1) and 96 % (2). Complex 2 exhibited higher turnover frequency relative to 1, while 1 showed lower overpotential (0.35 V) in comparison to 2 (0.45 V). The stability of the complexes and the amount of produced H2 has been investigated by bulk electrolysis study. A tentative mechanism (ECEC; E, electrons and C, chemical steps) and involved intermediate species for the proton reduction reaction for 1 has been established by theoretical studies.

Determination and correlation of the solubility of magnesium sulfate in ethanol solutions with different concentrations: Application to the removal of magnesium from zinc electrolytic waste solution

In this study, the solubility of anhydrous magnesium sulfate (MgSO4) in ethanol solutions with concentrations ranging from 10 % to 50 % was determined at 15–50 °C. Next, the results were correlated by using the Apelblat model, polynomial empirical equation, ideal solution equation of state model, and Van’t Hoff–Jouyban–Acree model. The results indicated that all four models exhibited correlation coefficients greater than 97 %, and average relative deviations of 3.82 %, 4.24 %, 3.96 %, and 3.96 %, respectively. Notably, the Apelblat model was found to be more accurate and reliable in correlating the solubility of MgSO4 in ethanol solutions with different concentrations. Further, the Van’t Hoff equation was applied to determine the enthalpy and entropy of dissolution. Herein, a certain amount of anhydrous ethanol was added to the zinc (Zn) electrolytic waste solution (ZEWS) to crystallize Zn2+ and Mg2+ through the solvent crystallization method, with the precipitation rates reaching 20.13 % and 39.38 %, respectively. The concentration of Mg2+ reduced to below 15 g⋅L−1, meeting the quality standard of ZEWS. The XRD, TG, and SEM analyses of the output salt mix crystallization confirmed the primary components to be MgSO4·7H2O and ZnSO4·7H2O, with the morphological features primarily consisting of short rods and some crystal agglomerates. This study shows that the removal of Mg2+ from Zn smelting process can be effectively achieved by the proposed solvent crystallization method.

On the resolution of the three-axis neutron diffractometer setting optimized for some powder diffractometry studies

Presented three-axis neutron diffractometer performance documents the feasibility of using it in special cases high-resolution powder diffraction studies, namely, for elastic and plastic deformation studies of bulk polycrystalline samples when the whole powder diffraction spectrum is not required. Contrary to the conventional double-axis setting the suggested alternative consists of an unconventional three axis set-up employing a bent perfect crystal (BPC) monochromator and analyzer with a polycrystalline sample in between. The analysis of the profile of the beam diffracted by a sample is carried out by rocking the BPC-analyzer and the neutron signal is registered by a point detector. Though the diffractometer alternative is, for measurements, much more time consuming, its resolution is, however, substantially higher and permits also plastic deformation studies on the basis of analysis of the sample diffraction profiles. The so-called analyzer rocking curve then provides a sample diffraction profile and could reflect the lattice or structural changes. Moreover, much larger widths (up to 10 mm) of the irradiated gauge volumes can be investigated when just slightly affecting the resolution of the experimental setting.

Crystal plasticity modeling and analysis for the transition from intergranular to transgranular failure in nickel-based alloy Inconel 740H at elevated temperature

The precipitation-strengthened Nickel-based alloy Inconel® 740H® (IN740H) exhibits increased ductility at higher applied strain rates during quasi-static tensile tests at an elevated temperature of 760 °C. The examination of fracture surfaces in this context reveals a noteworthy transition of underlying fracture mechanisms from transgranular to intergranular fracture as the applied strain rate decreases from 1×10−3/s to 0.83×10−4/s. To thoroughly understand the mechanical response of IN740H under these conditions, this study develops a crystal plasticity finite element (CPFE) model. This model incorporates various deformation mechanisms including dislocation slips, climb, and grain boundary sliding, which are relevant to the test conditions. The model is calibrated using data from both tensile tests at different strain rates and creep tests across a broad stress range at 760 °C, enabling the accurate determination of model parameters for each mechanism. Simulation results well captured the experimental observations of different failure modes. At higher strain rates, the model shows a dominance of dislocation slip leading to heterogeneous plastic deformation and formation of transgranular shear bands causing the failure, while at lower strain rates, an increased activity of grain boundary sliding causes grain boundaries crack leading to intergranular failure.

Predicting plastic behavior of magnesium alloy tube bending with comprehensive constitutive models

This paper aims to predict defects occurring in magnesium alloy tube bending through finite element simulations. Deformation tests were conducted to identify and characterize plastic anisotropy, tension-compression asymmetry, and anisotropic hardening behaviors of extruded Mg–Al–Zn-RE alloy rectangular tubes. Limited by size, the deformation tests along the wall thickness of specimens were conducted through crystal plasticity analysis. To thoroughly investigate the material constitutive features affecting bending, two constitutive models, Yoon2014 and Hill48, were established and calibrated. The non-associative flow rule was adopted, and anisotropic hardening was depicted using the yield-surface interpolation method. In comparison, the Yoon2014 model accurately predicted the strain distribution and tube shape collapse of the bent tube with negligible deviation from the experimental data, prior to the Hill48 model. This underscores the necessity of considering comprehensive plasticity models in tube bending simulations.

Exploring the structure and dynamics of a fluorescent schiff base (1E,1′E)-1,1′-(1,4-phenylene) bis(N-(4-chlorophenyl) methamine: Synthesis, spectroscopic analysis, thermal, electronic and crystallographic study with biological applications

Schiff bases have emerged as attractive biological agents with a wide range of uses due to the extraordinary physical, chemical, and pharmacological characteristics that they possess. This study focuses on the effective synthesis of a Schiff base that is produced from 4-chloroaniline and terephthaldehyde. The success of this synthesis is supported by a variety of spectroscopic methods and Single crystal XRD analysis. The chemical that was synthesised had significant fluorescence qualities, with measured values at 457.13, 481.49, and 524.15 nm, highlighting the fact that it has the potential to be utilised in a variety of applications within the field. Using thermogravimetric analysis, the thermal stability of the compound was studied, which revealed an excellent stability at 399 °C. Thermal stability is an essential component of compound usefulness. Molecular insights were obtained by the utilisation of Density Functional Theory, which revealed an energy gap of 1.70 electron volts (eV) and electrophilic behaviour in certain atoms. The distribution of charges was brought to light through the use of Mulliken charges and molecular electrostatic potential analysis, which brought attention to the distinctive qualities of the subject molecule. An examination of the electron localization function revealed that the electron density inside carbon, nitrogen, and chlorine atoms had been delocalized. Additionally, the localised orbital locator wave function and reduced density gradient maps offered vital insights into the non-covalent interactions that were taking place within the system under investigation. In the course of the evaluation of antimicrobial efficacy, it was discovered that the chemical exhibited more powerful antibacterial activity against gram-positive B. subtilis than the conventional antibiotic amoxicillin. The antibacterial findings were further supported by molecular docking tests, which involved using particular proteins from the target species. These investigations showed that B. subtilis had a higher affinity for binding. These findings were further validated by molecular dynamic simulations. The synthesised chemical was subjected to in silico toxicity assessment using seven models, which demonstrated its non-irritating properties on the skin and eyes. The extensive analysis that is given here lays the groundwork for more targeted research on novel antibacterial drugs, with a particular focus on the safety, molecular interactions, and effectiveness of these compounds. As a result of the compound's potential applicability in biocompatible antimicrobial formulations, it is a viable candidate for improving the development of antibacterial medicines that are both effective and safe.

Refinement of the crystal structure of christofschäferite-(Ce) and the modular aspect of the chevkinite polysomatic series with the general formula of {A<sub>4</sub>B(T<sub>2</sub>O<sub>7</sub>)<sub>2</sub>}{C<sub>2</sub>D<sub>2</sub>O<sub>8</sub>}<sub>m</sub> (m = 1, 2)

Research subject. The crystal structure of christofschäferite-(Ce) was previously refined in terms of the P21/m low-symmetrical space group, which allowed the local features of cationic arrangements to be determined. In this work, we set out to refine the crystal structure of christofschäferite-(Ce) in terms of the P21/a high-symmetrical space group based on the previously collected diffraction data. A topology-symmetrical analysis of the members of the chevkinite group with the general formula of A4BC2D2(Si2O7)2O8 was conducted. Materials and methods. A magmatic rock sample with christofschäferite-(Ce) inclusions was found in the vicinity of the Laacher See volcano, near Mendig, Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany. The crystal structure was studied using single-crystal X-ray analysis. Results. Despite an increase in the symmetry to the P21/a space group (in comparison with the previous data with the P21/m space group), the main patterns of cation distribution between the octahedral and tetrahedral sites are preserved. However, due to the lover number of cationic sites, this distribution becomes more disordered. Based on a crystal chemical analysis of the crystal structures of natural and synthetic members of the chevkinite group in the framework of the OD theory, it is possible to combine them into a united OD family with the same OD groupoid. Conclusions. According to the OD theory, there are two structural OD-subgroups of the chevkinite group (chevkinite and perrierite). The crystal structure and symmetry of possible MDO-polytypes are predicted.

Development of Inhibitory Compounds for Metallo-beta-lactamase through Computational Design and Crystallographic Analysis.

Metallo-β-lactamases (MBL) deactivate β-lactam antibiotics through a catalytic reaction caused by two zinc ions at the active center. Since MBLs deteriorate a wide range of antibiotics, they are dangerous factors for bacterial multidrug resistance. In this work, organic synthesis, computational design, and crystal structure analysis were performed to obtain potent MBL inhibitors based on a previously identified hit compound. The hit compound comprised 3,4-dihydro-2(1H)-quinolinone linked with a phenyl-ether-methyl group via a thiazole ring. In the first step, the thiazole ring was replaced with a tertiary amine to avoid the planar structure. In the second step, we virtually modified the compound by keeping the quinolinone backbone. Every modified compound was bound to a kind of MBL, imipenemase-1 (IMP-1), and the binding pose was optimized by a molecular mechanics calculation. The binding scores were evaluated for the respective optimized binding poses. Given the predicted binding poses and calculated binding scores, candidate compounds were determined for organic syntheses. The inhibitory activities of the synthesized compounds were measured by an in vitro assay for two kinds of MBLs, IMP-1 and New Delhi metallo-β-lactamase (NDM-1). A quinolinone connected with an amine bound with methyl-phenyl-ether-propyl and cyclohexyl-ethyl showed a 50% inhibitory concentration of 4.8 μM. An X-ray crystal analysis clarified the binding structure of a synthesized compound to IMP-1. The δ-lactam ring of quinolinone was hydrolyzed, and the generated carboxyl group was coordinated with zinc ions. The findings on the chemical structure and binding pose are expected to be a base for developing MBL inhibitors.

Analysis of creatinine crystals in urine by spectrophotometric and chromatographic methods

Analysis of creatinine crystals in urine by spectrophotometric and chromatographic methods

Experimental and Theoretical Investigation on the SR method grown Semi-Organic Piperazinium Tetrachlorozincate Monohydrate (PTZM) Single Crystal for Optoelectronic Applications

Efficient semi organic nonlinear optical (NLO) Piperazinium Tetrachlorozincate monohydrate (PTZM) [C4H12N2][ZnCL4].H2O single crystals have been grown by slow evaporation solution technique (SEST) and Sankaranarayanan-Ramasamy (SR) method using water as solvent. Single crystal X-ray diffraction (SXRD) analysis reveals the unit cell parameters of the grown crystal. The morphology of the grown crystal was identified by the single crystal XRD analysis. The electrical properties, dielectric constant, dielectric loss and piezoelectric (d33) coefficient were determined. The etch pit density of PTZM crystal has been calculated by using the chemical etching analysis. The laser damage threshold (LDT) analysis was investigated by Nd: YAG laser and the wavelength of laser is 1064nm. The mechanical stability of the grown PTZM crystal was studied using Vickers microhardness measurement. Utilizing quantum chemical calculations, the PTZM compound is analyzed for vibrational properties, HOMO and LUMO characteristics, NBO interactions, and the determination of first-order hyperpolarizability. The nonlinear susceptibility and first-order hyperpolarizability results provide compelling evidence and affirm the PTZM molecule’s potential as a strong candidate for nonlinear optical (NLO) applications.

Synthesis, Characterization and Antimicrobial Activity of V(IV) Complexes Containing 2,6-Pyridinedicarboxylate (DPA) Ligand

A novel molecular coordination compound, [V4IVO4(DPA)4(OH2)4]∙2H2O, 1, and known [VIVO(DPA)(OH2)2].2H2O compound, 2, were obtained from V2O5 and 2,6-pyridine dicarboxylic acid (H2DPA) reactions with water or ethyl alcohol by using hydro/solvothermal synthetic methods. 1 was fully characterized by IR spectroscopy, manganometric titration, magnetic susceptibility, thermogravimetric and single crystal XRD analyses. The single-crystal XRD analysis revealed that it was a molecular consist of four-nuclear coordination compound. DPA ligand in 1 acted chelating and bridging modes through carboxylate groups. Four V(IV) ions exhibit a distorted octahedral coordination geometry {VNO5}. 1 and 2 were investigated for antimicrobial activity. The results of antimicrobial activity show that they have an antimicrobial effect against the microorganisms P. aeruginosa, E. coli, S. aureus, E. faecalis, L. monocytogenes, B.subtilis, C. albicans.

Palladium-Catalyzed Arylation of C(sp2)-H Bonds and C(sp3)-H Bonds with 4-Amino-benzotriazole as the Bidentate Directing Group.

The arylation of C(sp2)-H and C(sp3)-H bonds in carboxylic acids catalyzed by Pd(II) with 4-aminobentriazole as the directing group was investigated. In addition to activation of the C(sp2)-H bond, selective arylation of alkyl carboxylic acids and amino acids in the β position can also be achieved. This strategy involved a 5,5-bicyclic Pd intermediate complex whose structure was determined by X-ray single crystal diffraction analysis. Importantly, the DG (directing group) can be easily removed under mild conditions.

Novel Insecticidal Butenolide-Containing Methylxanthine Derivatives: Synthesis, Crystal Structure, Biological Activity Evaluation, DFT Calculation and Molecular Docking.

The design of novel agrochemicals starting from bioactive natural products is one of the most effective ways in the discovery and development of new pesticidal agents. In this paper, a series of novel butenolide-containing methylxanthine derivatives (Ia-Ir) were designed based on natural methylxanthine caffeine and stemofoline, and the derivatized insecticide flupyradifurone of the latter. The structures of the synthesized compounds were confirmed via1H NMR, 13C NMR, HRMS and X-ray single crystal diffraction analyses. The biological activities of the compounds were evaluated against a variety of agricultural pests including oriental armyworm, bean aphid, diamondback moth, fall armyworm, cotton bollworm, and corn borer; the results indicated that some of them have favorable insecticidal potentials, particularly toward diamondback moth. Among others, Ic and Iq against diamondback moth possessed LC50 values of 6.187 mg·L-1 and 3.269 mg·L-1, respectively, -- 2.5- and 4.8-fold of relative insecticidal activity respectively to that of flupyradifurone (LC50 = 15.743 mg·L-1). Additionally, both the DFT theoretical calculation and molecular docking with acetylcholine binding protein were conducted for the highly bioactive compound (Ic). Ic and Iq derived from the integration of caffeine (natural methylxanthine) and butenolide motifs can serve as novel leading insecticidal compounds for further optimization.

SYNTHESIS AND CHARACTERIZATION OF CaO PREPARED FROM LIMESTONE USING SOL-GEL METHOD

The sol-gel method has been successfully applied to the synthesis and characterization of calcium oxide (CaO) derived from calcite-based natural limestone from Pamekasan, Madura, East Java Indonesia. Controlled dissolution, titration, gel formation, and subsequent calcination at temperatures 650°C and 900°C were the steps involved in the synthesis. X-ray diffraction was used for characterization to identify the phase that had formed. Supporting software, MATCH! used to analyze the phases and structures and Rietica for refinement using the Rietveld method. The Ca(OH)2 phase formed was 59.65 ± 2.45 %wt before the calcination process, according to the XRD results. 23.71 ± 0.61 %wt CaO was produced by the calcination process at 650°C, and 64.52 ± 1.85 %wt was produced at 900°C. Meanwhile, after calcination at 900°C, crystal size analysis using MAUD software produced CaO with a size of 534 ± 74 nm. K CaO powder synthesized using the sol-gel method is calcined at 900°C to get a higher percentage than at 600°C. The CaO powder can be used for CO2 capture applications because it comes from natural resources and is environmentally friendly.

Pyrrole-substituted difluoroboron β-diketonate dyes: Facile synthesis and multi-state optical properties

Difluoroboron β-diketonate complexes (BF2bdks) are classic fluorescent molecules that have been applied in luminescent materials, oxygen and mechanical sensors, and most investigations concentrate on BF2bdks with varying aromatic groups without heteroatoms. In this work, a new molecular platform BF2bdks with heterocycle-substituted is prepared in one pot, and six unsymmetric π-expanded BF2bdks are synthesized via condensation reaction. B-1∼6 exhibit comparable fluorescence properties in solution, aggregated and solid states. B-3 (683 nm, Φf = 13.1 %) and B-5 (700 nm, Φf = 2.1 %) show near infra-red (NIR) emission with moderate fluorescence intensity in solution state. Solid emission of B, B-1-3 and B-5 are detected with fluorescence quantum yield from 12.8 % to 25.6 %, and B-2, B-3 and B-5 show AIE phenomenon in aggregated state. The results are supported by crystal analysis and DFT calculation in some extent. In a word, this work enriches the heterocycle-substituted BF2bdks system. B-3 and B-5 with moderate intensity NIR emission in solution, aggregated and solid states at the same time, providing a simple preparation method for multi-states luminescent dyes.

Single component long-lived dynamic room temperature phosphorescence with large-scale preparation and visible light excitation

A pure organic room temperature phosphorescence (PORTP) luminogen named as DCP was successfully prepared and showed long room temperature phosphorescence (RTP) and afterglow lifetimes (3 ms and 4 s in sequence). Meanwhile, DCP showed high fluorescence (0.14) and RTP (0.39) quantum yields in crystalline state, simultaneously presented visible light excitation and dynamic RTP. By host-guest doping and optimization, Urea/DCP doping system emitted blue RTP, with RTP and afterglow lifetimes of 341 ms of 5 s in turn. Crystal analysis and theoretical calculations indicated H stacking, large spin orbit coupling constant, and small energy gap between the lowest singlet and triplet states result in long RTP lifetime and high quantum yield for DCP. Based on long phosphorescence emission, an advanced anti-counterfeiting pattern was constructed. As far as we know, it is the first report that such small molecules containing 3, 5-dicyanopyridine show long-lived RTP in both crystalline state and doping system. In this paper, not only ultralong and blue PORTP materials with the advantage of large-scale preparation, but also single component dynamic RTP, and RTP of visible light excitation were achieved.

Air-Stable Cobalt(III) and Chromium(III) Complexes as Single-Component Catalysts for the Activation of Carbon Dioxide and Epoxides.

Cobalt(III) and chromium(III) salophen chloride complexes were synthesized and tested for the cycloaddition of carbon dioxide (CO2) with epoxides to obtain cyclic carbonates. The cat1, cat2, cat4, and cat5 complexes presented high catalytic activity without cocatalysts and are solvent-free at 100 °C, 8 bar, and 9 h. At these conditions, the terminal epoxides (1a-1k) were successfully converted into the corresponding cyclic carbonates with a maximum conversion of ∼99%. Moreover, cat5 was highlighted due to its capability of opening internal epoxides such as limonene oxide (1l) with a 36% conversion to limonene carbonate (2l), and from cyclohexene oxide (1m), cyclic trans-cyclohexene carbonate (2m) and poly(cyclohexene carbonate) were obtained with 15% and 85% selectivity, respectively. A study of the coupling reaction mechanism was proposed with the aid of electrospray ionization mass spectrometry (ESI-MS) analysis, confirming the single-component behavior of the complexes through their ionization due to epoxide coordination. In addition, crystallographic analysis of cat1 single crystals grown in a saturated solution of pyridine helped to demonstrate that the substitution of chloride ion by pyridine ligands to form an octahedral coordination occurs (Py-cat1), supporting the proposed mechanism. Also, a recyclability study was performed for cat5, and a total turnover number of 952 was obtained with only minor losses in catalytic activity after five cycles.

Crystal Plasticity Finite Element Analyses on the Formability of AA6061 Aluminum Alloy with Different Ageing Treatments

Different ageing treatments have been developed to achieve targeted properties in aluminum alloys through altering microstructures. However, there is a lack of understanding regarding the effect of ageing treatments on the formability of these alloys. In this study, we employed crystal plasticity finite element (CPFE) modeling, in conjunction with the Marciniak-Kuczynski (M-K) approach, to investigate the effects of ageing treatments on the mechanical properties and formability of AA6061 aluminum alloy. The as-received sheet was in the T6 heat treatment state, which was subjected to artificial ageing and pre-ageing, respectively, to achieve two age-hardened alloys with modified precipitation states. The microstructures and crystallographic textures of the three alloys were measured using the electron backscattering diffraction (EBSD) technique, and uniaxial tensile tests were performed along the rolling direction (RD), transverse direction (TD), and diagonal direction (DD, 45° to the RD) for each alloy. The forming limit curve (FLC) of the as-received alloy was determined using the Nakazima test. The dependence of mechanical strength, tensile ductility, and work-hardening behavior on the ageing treatments was clarified. Then, the tensile test results were utilized to calibrate the modeling parameters used in the CPFE model, whereas the FLC predictability of the developed model was validated with the experimental one. In the formability analysis, the effects of the ageing treatment on the FLC exhibit a notable dependency on loading paths, and the pre-aged alloy exhibits better formability than the other two at the plane strain tension state, thanks to its high work-hardening levels. In addition, the deformed textures along the different loading paths and the effects of the initial texture on the FLC are also discussed.

Tau-borides (Mnx{Ru,Os,Ir}1-x)23B6: X-ray single crystal and TEM data, physical properties

Investigation (electron microprobe and X-ray powder and single crystal diffraction analyses) of the phase relations in the Mn-rich corner (> 45 at% Mn) of the systems Mn-{Ru,Os,Ir}-B, prompted in all three systems a ternary compound with formula (Mnx{Ru,Os,Ir}1-x)23B6. For the systems Mn-Ru-B, Mn-Ir-B phase equilibria have been determined at 950°C (Ru), 900°C (Ir) revealing in both cases a small homogeneity region at constant B-content (Mn1-xRux)23B6 (0.29 < x < 0.37); (Mn1-xOsx)23B6 (0.33 < x < 0.37), as well as (Mn1-xIrx)23B6 (0.29 < x < 0.34). The crystal structure of the three compounds was determined from single crystal and X-ray powder intensity data analyses to be isotypic with the Cr23B6-type (so-called tau-phase, space group Fm3¯m, No. 225). In all cases Mn atoms fully occupy the 4a site (0,0,0) at the origin of the unit cell. For the 8c site (¼,¼,¼) we observed a random distribution of Mn1-x(PM)x with decreasing PM content (PM stands for a platinum group metal atom) going from Ru to Os and Ir, where Mn atoms fully occupy 8c. Whereas the remaining sites (48h, 32f) show various ratios of the two metal species, boron atoms fully occupy the centers (24e site) of the Archimedean metal atom antiprisms. A transmission electron microscopic study confirms the absence of superstructures related to these metal atom disorder, thus Mn and PM atoms randomly share their sites. The latter is well reflected in the behavior of the electrical resistivity of these compounds, which is dominated by disorder scattering. For (Mn0.6{Ru,Os}0.4)23B6, temperature dependent dc magnetization studies reveal distinct antiferromagnetic-like anomalies at TN ≅ 72 K and 114 K, respectively. Low field dc and ac magnetic susceptibility data of (Mn0.7Ir0.3)23B6 display a distinct ferromagnetic-like transition at TC = 280 K, consistent with a pronounced specific heat anomaly and a rather continuous temperature dependent evolution of magnetic anisotropy effects. Mechanical properties (hardness) characterize the tau phases among rather hard and brittle intermetallics (about 5–6 GPa).

Manipulating Single‐Molecule Exciplex TADF and Deep‐Blue RTP Through Non‐Covalent π–π Interaction in a Molecular Foldamer

AbstractAlthough the π–π stacking has been widely applied for constructing aggregated emitters in optoelectronics fields, the role of intramolecular non‐covalent π–π interactions has not been well studied. Here, a supramolecular foldermer M‐σ‐C, with the electron donor (D) and acceptor (A) units spatially separated with a non‐covalent bond at a close distance by methylene linker is designed and synthesized. This gives a face‐to‐face D/A stacking configuration with supramolecular π–π interactions. Temperature‐dependent nuclear magnetic resonance measurements and single crystal analyses confirm its folding configuration. In solutions, M‐σ‐C exhibits a single‐molecule exciplex thermally activated delayed fluorescence (TADF) property ascribing to the efficient intramolecular through‐space charge transfer (CT) process. While single‐molecule deep‐blue room temperature phosphorescence (RTP) with a long afterglow lifetime of 236 ms is observed in a nonpolar matrix, which represents the record lifetime among current 3CT‐character featured RTP. This work indicates that intramolecular non‐covalent interactions play an important role in manipulating high‐performance single‐molecule exciplex TADF and RTP, and provide a feasible molecular design strategy for supramolecular chemistry involving the development of optoelectronic materials.