Space Group Pna21 Research Articles

Structural, linear optical, second and third-order nonlinear optical properties of two halogenated chalcone derivatives containing thiophene moiety

Two halogenated chalcones B3B2SC and C3B2SC were synthesized for NLO applications. Single-crystal X-ray diffraction, spectroscopic (NMR and FT-IR), thermal and DFT studies were performed. Both the crystals are crystallized in the monoclinic non-centrosymmetric Pn space group. The SHG efficiency of both the chalcones is higher than urea. The third-order NLO parameters, optical limiting and optical switching properties of the chalcones were investigated by Z-scan method using a CW laser at 532 nm. The experimental and computational linear and nonlinear optical studies revealed that both the chalcone are promising materials for NLO applications.

Temperature-dependent magnetic and electrical properties of Cr-doped AlFeO3 ceramics

ABSTRACT The solid-state reaction method was selected to prepare polycrystalline AlFe1−x Cr x O3 (x = 0, 0.02, 0.05, 0.07 and 0.1) samples. The Samples were found to be pure phases possessing the orthorhombic space group Pna21. The unit cell volume decreased with increases in the Cr content. The magnetic transition temperature and the saturation magnetization of the ceramics decreased due to dilution of the magnetic interaction with Cr content. The Dielectric responses were systematically investigated by temperature-dependent dielectric/impedance spectroscopy from 160 K to 500 K. It was noticed that incorporation of Cr3+ in the structure led to an increase in the dielectric constant up to x = 0.05 before decreasing, whereas the dielectric loss decreased. Two different dielectric relaxation processes that occurred in the grain interior of AlFe1-xCrxO3 polycrystals were clarified. One relaxation process was thought to be associated with localized transfer of electrons between Fe3+ and Fe2+, while the other arising at low temperature was assigned to interplay between lattice and polaronic defects such as oxygen vacancies.

Synthesis and crystallographic characterization of N-allyl-N-benzyl-4-methylbenzenesulfonamide

N-Benzyl-4-methylbenzenesulfonamides were prepared via a two-step synthetic process involving the treatment of 4-methylbenzenesulfonyl chloride with a primary amine to give the corresponding 4-methylbenzenesulfonamide. Benzylation of the sulfonamide affords the substituted N-benzyl-4-methylbenzenesulfonamides. The similarities between the two steps of synthesis lend credence to the development of a one-pot synthesis of substituted N-benzyl-4-methylbenzenesulfonamides from 4-methylbenzenesulfonyl chloride. This method was applied to the synthesis of N-allyl-N-benzyl-4-methylbenzenesulfonamide and characterized through spectroscopic and crystallographic means. The crystal structure of N-allyl-N-benzyl-4-methylbenzenesulfonamide was obtained by single-crystal X-ray diffraction. The crystal structure reveals an orthorhombic Pna21 space group with cell parameters a = 18.6919 (18) Å, b = 10.5612 (10) Å, c = 8.1065 (8) Å, V = 1600.3 (3) Å3 and Z = 4, T = 173.15 K, μ(MoKα) = 0.206 mm-1, Dcalc = 1.251 g/cm3, 14455 reflections measured (4.36° ≤ 2Θ ≤ 54.96°), 3619 unique (Rint = 0.0439, Rsigma = 0.0429) which were used in all calculations. The final R1 was 0.0428 (I > 2σ(I)) and wR2 was 0.1079 (all data). Molecules are linked through C-H···N hydrogen bonds and C-H···π interactions.

Dinuclear mixed valence cobalt(II/III) and hetero-tetranuclear cobalt(III)/Na complexes with a compartmental ligand: Synthesis, characterization and use as catalysts for oxidative dimerisation of 2-aminophenol

A N2O4 donor compartmental reduced Schiff base ligand, H2L [(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol)], obtained on 1:2 condensation of 2,2-dimethyl-1,3-propanediamine with ortho-vanillin followed by reduction with NaBH4 in methanol solution, has been used to prepare two cobalt complexes, [(N3)CoIIIL(µ-OAc)CoII(N3)] (1) and [(μ-N3)2{(AcO)CoIIILNa(CH3OH)}2]·2CH3OH (2). Complex 1 is a dinuclear mixed valence cobalt(III)/cobalt(II) complex with CoIIIO2CoII core. Complex 2, on the other hand, is a tetranuclear cobalt(III)/sodium complex with CoO2Na(N3)2NaO2Co core. Formation of complex 1 or 2 is mainly governed by the amount of cobalt(II) precursors present in the reaction mixture. Each complex has been characterized by elemental and spectral analysis. X-ray diffraction analysis has confirmed their structures. Complex 1 crystallized in a chiral space group Pna21 where both the cobalt(III) and cobalt(II) centers adopt six-coordinate distorted octahedral geometry with cobalt(III) and cobalt(II) centers residing respectivelyat inner N2O2 and outer O4 cavities of the reduced Schiff base. Complex 2 crystallized in triclinic system with P1-space group, where both cobalt(III) and sodium centers adopt distorted octahedral geometry. Oxidation states of cobalt centers have been confirmed by bond length consideration, BVS calculations as well as from room temperature magnetic moment measurement. Both complexes 1 and 2 show phenoxazinone synthase mimicking activity with kcat values 250.21 and 493.73 h−1 respectively.

Synthesis, crystal growth, spectroscopic characterization and DFT studies of 4-(E)-1-(4-chlorophenyl)-3-(4-nitrophenyl)prop-2-en-1-one (CPNP) single crystal as a nonlinear optical (NLO) material

Abstract An organic nonlinear optical single crystal of 4-(E)-1-(4-chlorophenyl)-3-(4-nitrophenyl) prop-2-en-1-one [CPNP] was synthesized and its single crystal grown by solution growth technique. XRD analysis of the CPNP single crystal confirms that the crystal belongs to orthorhombic system with non centrosymmetric space group Pna21. The characteristic functional groups in the crystal were identified by FT-IR analysis. The CPNP crystal exhibits an optical transparency of 76% with optical band gap energy of 2.88eV. The HOMO-LUMO energy gap calculated from DFT for a single-molecule in the gas phase was found to be 3.88 eV. The thermal stability of the CPNP crystal was analyzed by TGA/DSC analysis. The CPNP crystal exhibits photoluminescence property with strong emission at 615nm in the orange red region. The LDT value of the CPNP crystal was found to be 1.72 GW/cm2. The SHG efficiency of CPNP crystal is 0.75 times greater than that of standard urea.

Synthesis, Crystal Structure, DFT Calculations and Hirshfeld Surface Analysis of 3-Chloro-2,6-Bis(4-Chlorophenyl)-3-Methylpiperidin-4-One

The 3-chloro-2,6-bis(4-chlorophenyl)-3-methylpiperidin-4-one (CCMP) compound have been characterized by FT-IR, 1H-NMR, 13C-NMR, 1H-1H NOESY spectroscopy and single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic space group Pna21. The single crystal measurements reveal a distorted chair conformation [puckering parameter Q = 0.557 (3) A°; θ = 167.8 (3)° and Ψ = 206.8 (13)°]. The optimized geometric parameters and frequency values were theoretically calculated using DFT/B3LYP method with B3LYP/6–31+G(d,p) basis set. The XRD single crystal measurement parameters are good agreed with the optimized parameters. The spectral and optimized parameters showed that the piperidine-4-one ring adopts normal chair conformation with equatorial orientations of all the substituents except chlorine. The frontier molecular orbitals HOMO and LUMO were computed to know the chemical reactivity and kinetic stability of the molecular compound. Hirshfeld surface analysis was also performed. Hirshfeld surface analysis (dnorm surface, two-dimensional fingerprint plots and molecular electrostatic potantials) revealed the nature of intermolecular interactions. The most important contributions for the crystal packing are from H···H (35%), Cl···H/H···Cl (32.3%), C···H/H···C (15%) and O···H/H···O (7.5%) interactions. In this study, spectroscopic properties of a new piperidine-4-one crystal compound and it’s DFT structural investigation compared with experimental were gained to literature.

Synthesis, growth and characterization of N, N-dimethyl-4-[2-(2-quinolyl) vinyl] aniline (DADMQ): An SHG material for NLO applications

The organic nonlinear optical (NLO) material N, N-dimethyl-4-[2-(2-quinolyl) vinyl] aniline (DADMQ) has been synthesized and high-quality single crystal with the dimension of 8 × 1 × 0.5 mm3 was grown from methanol solvent by slow cooling method for the first time. Single crystal and powder XRD studies show that DADMQ crystal belongs to the orthorhombic space group Pna21. All the functional groups and structure of the synthetic material can be determined from FT-IR and 1H NMR spectral analyses. The thermal properties can be studied through TG/DTG and DSC analyses, and its melting point is confirmed at 184.9 ℃. Some critical optical characteristics like the optical transmittance, optical absorption coefficient (α), energy band gap (Eg), cut-off wavelength (λmax) and extinction coefficient (κ) can be carried out through UV–vis-NIR spectral analysis. The dielectric features of the title crystal have also been measured. Furthermore, there is a blue emission appeared at 493 nm through PL spectral analysis. The second harmonic generation (SHG) efficiency of the title crystal has been measured, which indicates that DADMQ has 3.64 times greater than KDP crystal.

Crystal and magnetic structure of polar oxide HoCrWO6

Polar magnetic oxide HoCrWO6 is synthesized and its crystal structure, magnetic structure, and thermodynamic properties are investigated. HoCrWO6 forms the polar crystal structure (space group Pna21 (#33)) due to the cation ordering of W6+ and Cr3+. There is an antiferromagnetic transition at TN = 24.5 K along with the magnetic entropy change (~5 J.Kg.−1K−1 at 70 kOe). Neutron diffraction measurement indicates that both Cr and Ho sublattices are ordered with the moment of 2.32(5)μB and 8.7(4)μB at 2 K, respectively. While Cr forms A-type collinear antiferromagnetic (AFM) structure with magnetic moment along the b axis, Ho sublattice orders in a non-coplanar AFM arrangement. A comparison with isostructural DyFeWO6 and DyCrWO6 indicates that the magnetic structure of this family of compounds is controlled by the presence or absence of eg electrons in the transition metal sublattice.

Synthesis, crystal structure, Hirshfeld surface and interaction energies analysis of 5-methyl-1,3-bis(3-nitrobenzyl)pyrimidine-2,4(1H,3H)-dione

The title compound 5-methyl-1,3-bis(3-nitrobenzyl)pyrimidine-2,4(1H,3H)-dione was obtained by reaction of thymine with 3-nitrobenzylbromide in the presence of cesium carbonate. Characterization of the product was achieved by NMR spectroscopy and its stability was probed in basic condition using UV-Visible analysis. Furthermore, the molecular structure was confirmed by X-ray diffraction analysis. The compound crystallizes in orthorhombic Pna21 space group with unit cell parameters a = 14.9594 (15) Å, b = 25.711 (3) Å, c = 4.5004 (4) Å, V = 1731.0 (3) Å3 and Z = 4. The crystal packing of the title compound is stabilized by intermolecular hydrogen bond, π···π and C−H···π stacking interactions. The intermolecular interactions were furthermore analyzed through the mapping of different Hirshfeld surfaces. The two-dimensional fingerprint revealed that the most important contributions to these surfaces come from O···H (37.1%), H···H (24%) and H···C/C···H (22.6%) interactions. The interaction energies stabilizing the crystal packing were calculated and were presented graphically as framework energy diagrams. Finally, the energy-framework analysis reveals that π···π and C−H···π interactions energies are mainly dispersive and are the most important forces in the crystal.

Crystal structure and Hirshfeld surface analysis of 2-{[(4-iodo-phen-yl)imino]-meth-yl}-4-nitro-phenol.

The title compound, C13H9IN2O3, was synthesized by a condensation reaction between 2-hy-droxy-5-nitro-benzaldehyde and 4-iodo-aniline, and crystallizes in the ortho-rhom-bic space group Pna21. The 4-iodo-benzene ring is inclined to the phenol ring by a dihedral angle of 39.1 (2)°. The configuration about the C=N double bond is E. The crystal structure features C-H⋯O hydrogen-bonding inter-actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the packing arrangement are O⋯H/H⋯O (26.9%) and H⋯H (22.0%) inter-actions.

Ultrasound-mediated catalyst-free protocol for the synthesis of bis-3-methyl-1-phenyl-1H-pyrazol-5-ols in aqueous ethanol

We report an efficient one-pot method for bis-3-methyl-1-phenyl-1H-pyrazol-5-ol derivatives under ultrasound irradiation using β-keto ester, phenylhydrazine, and benzaldehydes as reactants in aqueous ethanol. Excellent yields (92–99%) obtained at RT in 5 to 8 min. Products were characterised by FT-IR, HRMS, 1H and 13C NMR analysis. We described the crystal structure of 2‑methoxy-phenyl compound 4a. Compound (C28H27N4O3) crystallised in the orthorhombic system with space group Pna21, and along the b-axis of the unit, cell contained four asymmetric molecules. The unit cell parameters were a = 17.2578(2) Å, b = 17.26256(2) Å, c = 7.76970(10) Å, α = β = γ = 90°, V = 2315.11(5) Å3, Z = 4. The crystal structure was stabilised by an intramolecular hydrogen bond (O—H…O). π-π intermolecular interactions existed between the phenyl and pyrazolone rings with 3.54 Å separation. The prominent features are catalyst-free, green protocol, simple work-up, rapid synthesis, excellent yields, and no column chromatography.

Three novel Cd(II) dithiocarbamate complexes: synthesis, structural diversity and fluorescence properties

Three new homoleptic cadmium (II) dithiocarbamate complexes having molecular formula [Cd(KL)2], (KL1 = C15H13N1F1S2) (1); (L2 = C13H11N1F1S2) (2); (L3 = C11H14N1O1S2) (3), have been synthesized and characterized by elemental analysis, spectroscopy (IR, 1H and 13CNMR and UV–Vis). Single crystal X-ray studies confirm that the complex 1 crystallises in Orthorhombic with space group Pna21 and holding dimeric structure. In this complex Cd2+ having distorted octahedral geometry about the metal centre forms 1D coordination polymeric structures. The dimeric form of complex 2 and 3 crystallizes in triclinic crystal lattice with space group P-1.

Nuclear and magnetic structures of KMnF3 perovskite in the temperature interval 10 K–105 K

Abstract The nuclear and magnetic structures of the perovskite-structured compound KMnF3 have been investigated using high resolution neutron powder diffraction techniques for the first time. Data have been collected in 1 K intervals from 105 K to 10 K to characterize previously identified structural phase transitions from Phase II (space group I4/mcm) – (88 K) Phase III (space group Cmcm) – (82 K) Phase IV (space group Pnma) using the diffractometer HRPD. In the temperature interval 91 K ≥ T ≥ 75 K, KMnF3 exhibits a temperature-dependent phase coexistence between phases with space groups I4/mcm and Pnma, contrary to the earlier interpretation, with no evidence found for a discrete phase with space group Cmcm. A recent revision of the space group of phase IV from Pnma to B21/m is critiqued and shown to be inconsistent with the neutron diffraction data. The magnetically ordered phases of KMnF3, collinear antiferromagnet for 81.5 K ≤ T ≤ 88.3 K, and canted antiferromagnet with a ferromagnetic component for T ≤ 81.5 K, have been investigated in detail in the temperature interval 90 K–83 K, in 0.2 K steps using the cold neutron diffractometer WISH, supplemented by lower temperature measurements using HRPD. At a temperature of ∼86.8 K, magnetic scattering is observed consistent with the development of a G-type spin configuration in the majority tetragonal phase with a moment direction parallel to the c-axis, propagation vector k = 0, magnetic space group I4/mcm. Below 75 K, in the pure orthorhombic phase, KMnF3 is found to inherit the G-type ordering parallel to c in magnetic space group Pn′ma’ which in addition permits A-type antiferromagnetic ordering, and ferromagnetic ordering along the a- and b-axes respectively.

Synthesis and Crystal Structure of Mn3Fe2(SeO3)6

Abstract Crystals of Mn3Fe2(SeO3)6 have been synthesized in the system MnCO3-FeC2O4·2H2O-H2SeO3-H2O at 220 °C and structurally characterized by single-crystal X-ray diffraction methods. The new compound is orthorhombic, space group Pna21 (a = 5.362 Å, b = 18.840 Å, c = 7.612 Å, Z = 4) building a complex framework from distorted Mn2+O6 polyhedra, Fe3+O6 octahedra and trigonal pyramidal SeO3 groups. Mean bond distances are ∼2.22 Å, 2.02 Å and 1.69–1.71 Å, respectively. Close relations with the structures of Cu3Fe2(SeO3)6-II and Cu3In2(SeO3)6 are evident.

Ammine Lanthanum and Cerium Borohydrides, M(BH4)3·nNH3; Trends in Synthesis, Structures, and Thermal Properties.

Ammine metal borohydrides show potential for solid-state hydrogen storage and can be tailored toward hydrogen release at low temperatures. Here, we report the synthesis and structural characterization of seven new ammine metal borohydrides, M(BH4)3·nNH3, M = La (n = 6, 4, or 3) or Ce (n = 6, 5, 4, or 3). The two compounds with n = 6 are isostructural and have new orthorhombic structure types (space group P21212) built from cationic complexes, [M(NH3)6(BH4)2]+, and are charge balanced by BH4-. The structure of Ce(BH4)3·5NH3 is orthorhombic (space group C2221) and is built from cationic complexes, [Ce(NH3)5(BH4)2]+, and charge balanced by BH4-. These are rare examples of borohydride complexes acting both as a ligand and as a counterion in the same compound. The structures of M(BH4)3·4NH3 are monoclinic (space group C2), built from neutral molecular complexes of [M(NH3)4(BH4)3]. The new compositions, M(BH4)3·3NH3 (M = La, Ce), among ammine metal borohydrides, are orthorhombic (space group Pna21), containing molecular complexes of [M(NH3)3(BH4)3]. A revised structural model for A(BH4)3·5NH3 (A = Y, Gd, Dy) is presented, and the previously reported composition A(BH4)3·4NH3 (A = Y, La, Gd, Dy) is proposed in fact to be M(BH4)3·3NH3 along with a new structural model. The temperature-dependent structural properties and decomposition are investigated by in situ synchrotron radiation powder X-ray diffraction in vacuum and argon atmosphere and by thermal analysis combined with mass spectrometry. The compounds with n = 6, 5, and 4 mainly release ammonia at low temperatures, while hydrogen evolution occurs for M(BH4)3·3NH3 (M = La, Ce). Gas-release temperatures and gas composition from these compounds depend on the physical conditions and on the relative stability of M(BH4)3·nNH3 and M(BH4)3.

Growth, experimental and theoretical investigations on 4-hydroxy-3-methoxybenzaldehyde 5-chloro-2-hydroxybenzoic acid: A new high second order nonlinear optical material

Novel 4-hydroxy-3-methoxy benzaldehyde 5-chloro-2-hydroxybenzoic acid (4H5C) organic co-crystal was grown by simple solution growth technique. 4H5C crystal exhibits the orthorhombic structure with non-centrosymmetric space group of Pna21 from single crystal X-ray diffraction study results. The cut-off wavelength and optical excitation wavelength was evaluated by using UV–Visible and PL spectral studies to the 4H5C heterodimer and suitability for the NLO applications are discussed. 4H5C single crystal material thermal stability and decomposition states were examined by using TG-DSC analysis. Vickers microhardness test was carried out on the flat surface of 4H5C crystal to understand the mechanical strength and behavior for weight loadings. Chemical etching patterns of 4H5C crystal surface was carried out and found the layer growth pattern. The second harmonic generation (SHG) efficiency of 4H5C single crystal was evaluated by Kurtz-Perry powder technique and result is compared with KDP crystal SHG efficiency. Polarizability, first order hyperpolarizability, geometric parameters of 45HC were evaluated theoretically by using B3LYP, CAMB3LYP methods of density functional theory by using 6-311++G (d,p) basis set. It is estimated that, the polarizability (3.38 x 10−23 e.s.u) and first order hyperpolarizability (9.370 x 10−30 e.s.u.) to the 4H5C heterodimer in B3LYP method.

First-principles identification of ferroelectric metal-organic frameworks of [CH3NH3][B(HCOO)3] (B = Mg, Ca, Sr, and Cd)

The ferroelectric instabilities of perovskite-type metal-organic frameworks (MOFs) of [CH3NH3][B(HCOO)3] (B = Mg, Ca, Sr, and Cd) were examined theoretically. Out of these four compounds, the highest ferroelectric instability was observed in [CH3NH3][Sr(HCOO)3]. Energy comparisons of the non-polar Pnma and polar Pna21 space groups confirmed that the polar space group is more stable than the non-polar space group in each compound, and the largest energy difference between these two space groups was found in the Sr-based compound. To determine why the Sr-based system shows the highest amplitude of a ferroelectric mode, the bond distance, including hydrogen bonds, was analyzed systematically. The shortest hydrogen bonds were found in [CH3NH3][Sr(HCOO)3].

Investigation of the magnetic behavior of the ferrites of alkali and alkaline earth metals for biomedical application

Superparamagnetic nanoparticles of KFeO2 and NaFeO2 have been synthesized by the sol-gel method. The synthesized nanoparticles have been characterized through various techniques transmission electron microscopy (TEM), x-ray diffraction (XRD) and magnetometer for analysis of their morphology, structural and magnetic properties. TEM study reveals that the average particle size of the nanoparticles is 12.30 nm and 10.50 nm for KFeO2 and NaFeO2 nanoparticles. XRD study reflects that the synthesised nanoparticles exhibit orthorhombic crystal structure with the Pbca and Pna21 space group for KFeO2 and NaFeO2, respectively. The magnetic analysis confirmed the superparamagnetic nature of the nanoparticles with large value of magnetization. The study reveals that the synthesized superparamagnetic nanoparticles can be used for the treatment of cancer and various other biomedical applications.

Structural transformation induced enhanced multiferroicity in Al3+ and Ti4+ co-doped LaFeO3

In order to enhance the magnetoelectric property of LaFeO3, we have considered co-substitution of Al3+ and Ti4+ in La3+ and Fe3+ sites. Rietveld refinement of the observed XRD patterns confirms that the pristine (LaFeO3, LFO) crystallizes in orthorhombic Pbnm (centrosymmetric) space group whereas the doped samples (La0.9Al0.1Fe0.9Ti0.1O3, LAFTO) crystallizes in orthorhombic Pna21 (non-centrosymmetric) space group due to co-doping of Al3+- Ti4+ in LFO. Analysis of magnetic data confirms the antiferromagnetic phase of LFO and LAFTO possess ferrimagnetic spin structure with enhanced magnetization. Besides this ferroelectric polarization at room temperature is also improved in the co-doped sample of LAFTO (Pmax = 0.25 µC/cm2). Spontaneous polarization is predicted from first principle calculation for LAFTO to be ~ 12.31 µC/cm2. The dielectric loss factor of LAFTO reduces significantly and the dielectric strength is also enhanced compared to that of LFO. Experimental results are in agreement with these findings extracted from ab initio calculations using density functional theory. The present doped sample LAFTO has improved magnetic, dielectric, ferroelectric properties and magnetoelectric coupling compared to that of LFO, would have the high potential for applications in multiferroic devices.

Crystal structure of mechanochemically synthesized Ag2CdSnS4

Abstract Ag2CdSnS4 was synthesized by a two step mechanochemical synthesis route. From a detailed analysis of the observed reflections in the X-ray powder diffraction pattern, the crystal structure proposed in the literature (space group Cmc21 [E. Parthé, K. Yvon, R. H. Deitch, Acta Crystallogr. 1969, B25, 1164–1174; O. V. Parasyuk, I. D. Olekseyuk, L. V. Piskach, S. V. Volkov, V. I. Pekhnyo, J. Alloys Compd. 2005, 399, 173–177]) is questionable. Our structural investigations presented in this contribution point to the fact that Ag2CdSnS4 crystallizes in the monoclinic wurtzkesterite-type structure (space group Pn). At around T = 200°C, a phase transition to the orthorhombic wurtzstannite-type structure (space group Pmn21) is observed.