Single-crystal Spectra Research Articles

Synthesis, crystal structure, spectroscopic characterization, chemical activity and molecular docking studies of (E)-2-(((3-chloro-4-methylphenyl)imino)methyl)-6-ethoxyphenol

In present study, title compound of (E)-2-(((3-chloro-4-methylphenyl)imino)methyl)-6-ethoxyphenol is successfully synthesized and characterized by single-crystal X-ray diffraction method, FT-IR, NMR and UV-Vis spectra. The theoretical optimized geometrical parameters, local and global chemical activity studies are calculated by using the Density Functional Theory (DFT) with the B3LYP method at 6-311G(d,p) bases set. Hirshfeld surface analysis has been performed to study the nature of intermolecular interactions within the crystal structure. The charge transfer of title molecule with DNA bases have been examined by electrophilic centered charge transfer (ECT) method. The molecular docking studies have been calculated to understand the nature of binding of the compound with dodecamer d(CGCGAATTCGCG)2 (PDB: 1BNA) and guanine-DNA (PDB: 4ENM).

Spectra and nature of the electronic states of [1]Benzothieno[3,2-b][1]benzothiophene (BTBT): Single crystal and the aggregates.

Absorption, fluorescence, and phosphorescence spectra of single crystals of [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and BTBT dispersed in frozen n-nonane, n-hexadecane, and dichloromethane matrices were studied at 5K. Observation of a new absorption band and related changes in the fluorescence to phosphorescence intensity ratio, when the concentration of BTBT in the matrix increased above 10-4M, indicated the presence of BTBT aggregates. Quantum-chemistry calculations performed for the simplest aggregate, isolated dimer, showed that its structure is similar to the "herringbone" element in the BTBT crystal unit cell and the lowest electronic excited singlet state of the dimer has the intermolecular charge-transfer character. A qualitatively different nature of this state in dimers and in crystals, when compared with the situation in BTBT monomer [locally excited (LE) state], is associated with a decrease in the intersystem crossing yield. The structured vibronic structure of phosphorescence spectra in the studied systems indicated LE character of the triplet states.

An ultrathin amino-acid based copper(II) coordination polymer nanosheet for efficient epoxidation of β-caryophyllene

• CuIle-e nanosheet and CuIle-m nanoshuttle were fabricated from natural amino acid. • Stable catalytic systems, CuIle-e /acetone/TBHP and CuIle-e /THF/O 2 /TBHP, were built. • Good yields (86.1% or 87.2%) for β-caryophyllene epoxide were achieved. • Superior recyclability of CuIle-e nanosheet was realized. Natural amino acids are important building blocks for the construction of intriguing coordination polymers (CPs) because of their abundance, inexpensiveness and environmental benignness. Herein, two copper(II) CPs, namely, 2D CuIle-e nanosheet ( e : ethanol) and 1D CuIle-m nanoshuttle ( m : methanol), were fabricated from L -isoleucine ( Ile ) and well characterized with single-crystal x-ray diffraction, XPS spectra, TEM and AFM, etc. More importantly, two novel and stable catalytic nanosystems, i.e. CuIle-e /acetone/TBHP ( tert-butyl hydroperoxide) and CuIle-e /THF/O 2 /TBHP, were thus conveniently built by using ultrathin 2D CuIle-e nanosheet (~ 2.3 nm) in suitable aprotic solvents. Under mild conditions, complete conversion of β-caryophyllene and good yields (86.1% or 87.2%) for β-caryophyllene epoxide were gained via CuIle-e /acetone/TBHP or CuIle-e /THF/O 2 (1 atm)/TBHP (10.0 mol%), respectively. Notably, ultrathin CuIle-e nanosheet showed fairly satisfactory stability, which may open a unique window for the facile fabrication of new amino-acid based CP nanosystems with outstanding catalytic performances in actual applications. Two amino acid-based ultrathin CP nanosystems, CuIle-e /acetone/TBHP and CuIle-e /THF/1 atm O 2 /TBHP, were employed for the highly efficient epoxidation of β-caryophyllene under mild conditions.

Electron paramagnetic resonance study of the paramagnetic centers in gamma-irradiated oxalic acid dihydrate single crystal

The Electron Paramagnetic Resonance (EPR) spectra of the radicals produced by γ-irradiation of a single crystal of oxalic acid dihydrate (C2H6O6) have been reported. The EPR spectra of gamma-irradiated single crystals of oxalic acid dihydrate have been studied for different orientations of crystals in a magnetic field. As a result of studies carried out along three axes, it has been determined that there are two biradicals. The EPR spectra have been investigated at temperatures between 125 and 450 K. The spectra have been found to be temperature independent. The g values of the radiation damage centers observed in oxalic acid dihydrate acid single crystal and the hyperfine structure constants of the free electron with nearby protons have been obtained from the single crystal EPR analysis.

Three pairs of sesquiterpene enantiomers from Chloranthus multistachys pei

Phytochemical investigation on the whole plant of Chloranthus multistachys pei (Chloranthaceae) afforded three pairs of new sesquiterpene enantiomers (+)/(−)-chlorantene M [(+)/(−)-1], (+)/(−)-chlorantene M1 [(+)/(−)-2] and (+)/(−)-chlorantene N [(+)/(−)-3]. The structures of new compounds were determined through spectroscopic techniques (HR-ESI-MS, 1 D and 2 D NMR), besides, their absolute and relative configurations were established by using Single-crystal X-ray diffraction analysis and CD spectrum. The anti-inflammatory potential of all compounds was evaluated by applying LPS induced RAW 264.7 macrophage inflammatory model, and the results were that none of these compounds showed activity (IC50 > 100 μM).

Two Anderson-type POM-based metal-organic complexes as multifunctional materials for electrocatalytic sensing and zinc-ion batteries

Two Anderson-type polyoxometalate (POM)-based metal-organic complexes (MOCs), {Cd(3-Hbpah)2(H2O)2[CrMo6(OH)5O19]}(1), {Zn(3-Hbpah)2(H2O)2[CrMo6(OH)5O19]} (2), (3-bpah = N,N′-bis(3-pyridinecarboxamide)-1,2-cyclohexane) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra and powder X-ray diffraction. Complexes 1–2 reveal similar 1D structure and can be taken as a kind of aqueous multifunctional materials. Their electrochemical sensing performance and energy storage performance as zinc-ion battery cathode were studied, respectively. Complexes 1–2 also exhibit high adsorption performance towards methylene blue and gentian violet, respectively.

Interference of exciton-polariton waves in GaSe nanocrystals

Absorption, reflection, photoluminescence and wavelength modulation transmission spectra of GaSe single crystals were investigated in temperature rage 300 – 10 K. From fitting of contours of excitonic reflection spectra parameters of excitons as energy of transversal exciton ω0 = 2.1212 eV, longitudinal transversal splitting ωLT = 2.3 meV, effective mass M = 2.5m0, background permittivity εb= 5.2 and damping constant γ = 1.4 were determined. Effective masses of electrons (mC1 = 0.37m0) and holes (mV1 = 2.13m0) in the Brillouin zone center were estimated. An interference of waves of upper and lower branches of exciton-polaritons was found out in wavelength modulation transmission spectra of GaSe nanocrystals.

Raman scattering of light on overtone states of transverse and longitudinal polar optical modes in a single crystal of lithium tantalate

Raman scattering spectra in single crystals of lithium tantalate at 180-degree scattering geometry in a wide spectral frequency range (50 ÷ 2800 cm−1) were studied. Raman peaks were found in 1300 ÷ 2000 cm−1 region with frequencies exceeding doubled frequencies of LiTaO3 crystal lattice fundamental vibrations of A1 and E-type. The conditions for the manifestation of bound polar phonons in lithium tantalate Raman spectra were analyzed. The spectral intensity of Raman scattering in the overtone region of the spectrum of lithium tantalate was calculated taking into account the presence of a biphonon, and a satisfactory agreement between theory and experiment was obtained.

Methylhydrazinium]2PbBr4, a Ferroelectric Hybrid Organic–Inorganic Perovskite with Multiple Nonlinear Optical Outputs

An expansive library of structurally complex two-dimensional (2D) and three-dimensional (3D) lead halide perovskites has emerged over the past decade, finding applications in various aspects of photon management: photovoltaics, photodetection, light emission, and nonlinear optics. Needless to say, the highest degree of structural plasticity enjoys the former group, offering a rich playground for modifications of relevant optoelectronic parameters such as exciton energy. Structural tailorability is reflected in the ease of modification of the chemistry of the organic layers residing between inorganic slabs. In this vein, we show that the introduction of methylhydrazinium cation (MHy+, CH3NH2NH2+) into 2D perovskite gives a material with a record low separation of the inorganic layers (8.91 Å at 300 K). Optical studies showed that MHy2PbBr4 features the most red-shifted excitonic absorption among all known A2PbBr4 compounds as well as a small exciton binding energy of 99.9 meV. MHy2PbBr4 crystallizes in polar Pmn21 symmetry at room emperature (phase III) and at 351 K undergoes a phase transition to modulated Pmnm phase (II) followed by another phase transition at 371 K to Pmnm phase (I). The ferroelectric property of room-temperature phase III is inferred from switching of the pyrocurrent, dielectric measurements, and optical birefringence results. MHy2PbBr4 exhibits multiple nonlinear optical phenomena such as second-harmonic generation, third-harmonic generation, two-photon excited luminescence, and multiphoton excited luminescence. Analysis of MHy2PbBr4 single-crystal luminescence spectra obtained through linear and nonlinear optical excitation pathways indicates that free exciton emission is readily probed by the ultraviolet excitation, whereas crumpled exciton emission is detected under two- and multiphoton excitation conditions. Overall, our results demonstrate that incorporation of MHy+ into the organic layer is an emergent strategy for obtaining a 2D perovskite with polar character and multifunctional properties.

Efficient Photogeneration of Hydrogen Boosted by Long-Lived Dye-Modified Ir(III) Photosensitizers and Polyoxometalate Catalyst

Efficient Photogeneration of Hydrogen Boosted by Long-Lived Dye-Modified Ir(III) Photosensitizers and Polyoxometalate Catalyst

Study of the influence of electronic radiation on the surface, structure and Raman spectrum of a TlInS2 single crystal

The effect of electrons on the surface, Raman spectra, structure and phase transition in a TlInS2 single crystal was studied. Irradiation of TlInS2 with electrons with an energy of 2 MeV and a fluency of 2 × 1017 electron/cm2 leads to an increase in the height of the bump and its width on the sample surface. Radiation treatment of TlInS2 with electrons indicates the appearance of new peaks at 204 cm−1, 224 cm−1 in the Raman spectra and stimulates the formation of a single-phase state with a hexagonal structure (space group P63/mmc).

Synthesis, growth, optical, thermal, electrical and third-order nonlinear properties of an organic single crystal guanidinium 3,5 dinitrosalicylate: A promising candidate for nonlinear optical applications

An organic single crystal guanidinium 3,5 dinitrosalicylate (GuDNS) was successfully grown using slow evaporation technique. The cell parameters of the GuDNS crystal were found using powder X-ray diffraction study. The UV–vis–NIR transmittance study of the titular crystal was analyzed and other optical constants such as extinction coefficient, reflectance, electrical conductivity, optical conductivity were also calculated. The emission spectrum of GuDNS single crystal was determined using photoluminescence study. Using TG-DTA spectrum, the thermal stability of GuDNS crystal was analyzed. The mechanical property of GuDNS crystal was examined using Vicker's microhardness analysis. The electrical properties such as dielectric constant and dielectric loss were recorded for different temperatures with varying frequencies. The third order nonlinear susceptibility of GuDNS crystal was found using Z-scan technique. The obtained results show that the grown GuDNS crystal could be a promising candidate for nonlinear optical applications.

Absence of magnetic order in dichloro [1,2-bis (diphenylphosphino) ethane] nickel2+ single crystal* *Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0403502), the National Natural Science Foundation of China, and Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2017483). A portion of this work was supported by the High Magnetic Field Laboratory

Dichloro [1,2-bis (diphenylphosphino) ethane] nickel2+ (NiCl2(dppe)) is an organic compound containing C26H24P2(dppe) molecules and Cl−, Ni2+ ions. The large-size NiCl2(dppe) single crystals with longest dimension of 4 mm were grown by the method of slow evaporation of organic solution. Single crystal x-ray diffraction spectrum indicates that the single crystal is of high quality. Magnetization results of the NiCl2(dppe) single crystals show an anisotropic paramagnetism behavior and diamagnetic background, which come from Ni2+ ions and benzene ring, respectively. However, according to the specific heat results with temperature down to 0.1 K and magnetic field up to 14 T, no expected field-induced quantum phase transition was observed in NiCl2(dppe) single crystals.

Synthesis, crystal structure and ionic conductivity of MgAl2X8 (X = Cl, Br)

MgAl2X8 (X = Cl, Br) was synthesized from MgX2 and AlX3, and the physical properties were evaluated by XRD, AC conductivity, and NMR. MgAl2Br8 has the same crystal structure as MgAl2Cl8 and belongs to the space group C2/c. MgAl2Cl8-yBry was also synthesized in the same manner as MgAl2Br8. MgAl2Cl8-yBry was found to have the same crystal structure as MgAl2Cl8 and forms a solid solution in all the synthesized compositions. From the Rietveld analysis of the XRD pattern, it was found that the arrangement of Cl and Br in the crystal had no order and occupied the halogen sites almost randomly. The AC conductivity of the obtained compound was lowest for MgAl2Cl8 and highest for MgAl2Cl2Br6. The conductivity of MgAl2Cl2Br6 at 400 K is 1.3 × 10−6 S/cm, and the Nyquist plot suggests that MgAl2Cl8-yBry is a magnesium ionic conductor. In the temperature range from room temperature to 412 K, there was no significant change in the 27Al NMR spectra of a MgAl2Br8 single crystal, and the effects of Mg2+ ionic conduction and the reorientation motion of AlX4ˉ anion were not observed.

Luminescence properties of large-size Li2MoO4 single crystal grown by Czochralski method

Large-size Li2MoO4 single crystal was successfully grown by Czochralski method using the polycrystalline Li2MoO4 bulks synthesized via the conventional solid-state reaction. The phase identification, thermal behavior and optical transmission spectra of Li2MoO4 single crystal were studied systematically. The band gap of Li2MoO4 was estimated from the transmission spectra according to Tauc and Menth’s law. The luminescence spectra and decay characteristics under 355 nm laser excitation were investigated in detail. Li2MoO4 single crystal had a wide luminescence peak around 540 nm as a result of intrinsic luminescence emission of tetrahedral MoO42-. The maximal luminescence intensity increased with the ambient temperature cooling down. Meanwhile, the luminescence decay times decreased monotonically with the temperature increasing from 42 K to 298 K.

ИК-активные фононы ионного кристалла LiNiPO-=SUB=-4-=/SUB=-

The results of an experimental study of the phonon spectrum of a LiNiPO4 single crystal by IR reflection spectroscopy are presented. The spectroscopic parameters of IR phonons are obtained. The observed number of phonons is mainly in agreement with the performed group-theoretical analysis, and the reasons for small discrepancies are discussed. With decreasing temperature, a hardening of phonon frequencies is observed, associated with temperature changes in the parameters of the crystal lattice.

Facile and environmentally friendly one-step synthesis of hexanuclear Cu(II)–Ni(II) and Cu(II)–Co(II) clusters and their binding interactions with bovine serum albumin

The novel hexanuclear {K6[Cu4Co2(μ3-OH)4(μ4-O)(OAc)8][Cu(OAc)4](OH)2}·3H2O (1) and {K6[Cu4Ni2(μ3-OH)4(μ4-O)(OAc)8][Cu(OAc)4](OH)2}·3H2O (2) clusters have been prepared. The clusters were synthesized by the self-assembly of Cu(OAc)2 and M(OAc)2 (M ​= ​Co, Ni) in aqueous solution without any additional other organic ligands. The two clusters were well-characterized with single-crystal X-ray diffraction, FT-IR spectra and elemental analyses. Crystallographic studies revealed that the molecular core type was M6(μ3-OH)4(μ4-O) in both 1 and 2. Solid-state DC magnetization indicated that 2 exhibited strong Ni–O–Ni associated antiferromagnetic interaction, while 1 displayed merely weak antiferromagnetic interaction. The protein binding affinity of two clusters was tested with bovine serum albumin (BSA). Both two clusters showed good affinity with BSA, with a binding constant (Kb) of 4.97 ​× ​104 ​M−1and 2.14 ​× ​104 ​M−1, respectively. Cytotoxic activity was performed by MTT assay. It was observed that the complex exhibited low toxicity against the SH-SY5Y and A549 cancer cells.

Two novel LMOFs based on the flexible 1, 3-bis(imidazol-1-ylmethyl)benzene: The synthesis, crystal structures and temperature sensing applications

Two novel coordination polymers (CPs), namely [Zn(cca)(mbix)] (complex 1) and [Cd2(IMB)2(mbix)2]•3H2O (complex 2) (H2cca = 4-carboxycinnamic acid, mbix = 1,3-bis(imidazol-1-ylmethyl)benzene, H2IMB = 4,4’-((1H-imidazole-1-yl)methylene)dibenzoic acid) have been synthesized by using the solvothermal method. The structure of complexes 1 and 2 were characterized with single-crystal X-ray diffraction analysis, IR spectra (IR), elemental analyses and thermogravimetric (TG) analysis. Good phase purity of complexes 1 and 2 were confirmed by powder X-ray diffraction (PXRD) tests. Complex 1 crystallizes in the orthorhombic space group Pna21. In complex 1, each Zn(II) ion is linked by two cca2− anions and two mbix ligands to generate a typical three-dimensional (3D) 4-fold interpenetrated diamondoid network. While, complex 2 crystallizes in the monoclinic system with P21/c space group and exhibits the 2D layer structure. Interestingly, complex 2 exhibits linear response toward to the ambient temperature variation and good reusability in the temperature sensing application, which suggests that the as-synthesized MOFs might be used as quantitative fluorescent thermometers.

New bioactive monoterpene indole alkaloid from Rinorea yaundensis Engl.

Extraction of the aerial part of Rinorea yaundensis has led to the isolation of a new monoterpene indole alkaloid (1) along with 10 known compounds (2–11) for the first time from this plant. Their structures were determined by HRMS and NMR spectroscopic analyses as yaundentine hydrochloride (1), N b-oxide of iso-reserpiline (2), iso-reserpiline (3), iso-carapanaubine (4), lichenxanthone (5), stigmastane-3,6-dione (6), methyl β-orcinol carboxylate (7), β−sitosterol-3-O-β-D-glucoside (8), betulinic acid (9), ursolic acid (10) and benzoic acid (11) while the stereochemistry and absolute configuration of 1 was confirmed by single crystal x-ray crystallography and circular dichroism CD spectrum. Yaundentine hydrochloride (1) exhibited pronounced antioxidant, urease and lipoxygenase inhibitory activities with IC50 values of 35.6 ± 0.23, 20.3 ± 0.58 and 29.6 ± 0.77 µM, respectively. Compound 1 also showed good antimicrobial activity against some Gram positive and negative bacteria.

Multiple Hydrogen Bond-Induced Structural Distortion for Broadband White-Light Emission in Two-Dimensional Perovskites

Low-dimensional hybrid lead-halide perovskites with broadband white-light emission upon near-UV excitation have attracted immense scientific interest due to their potential application for the next...