Effect of α-Fe2O3 Phase on the Magnetic Interactions in Nickel Ferrite (NiFe2O4) Nanoparticles.

We report on the effect of α-Fe2O3 phase in the magnetic properties and magnetic interactions in nickel ferrite (NiFe2O4-NFO) nanoparticles synthesized by co-precipitation method. Structural analysis confirms the formation of the cubic inverse spinel phase without any impurities for the NFO sample annealed in air at 650 °C. When the annealing temperature is increased to 750 °C and 850 °C, α-Fe2O3 impurity phase is formed along with the parent NFO phase. Raman spectra recorded at room temperature (RT) confirm the presence of pure NFO phase for the sample annealed at 650 °C, and presence of α-Fe2O3 phase is observed in the samples annealed at 750 °C and 850 °C. Saturation magnetization values at RT for the NFO samples annealed at 650 °C, 750 °C and 850 °C are 34 emu/g, 19 emu/g and 28 emu/g respectively. Zero Field Cooled (ZFC) and Field Cooled (FC) measurement reveals the super-paramagnetic behavior along with competing magnetic interactions in all the samples. For the NFO sample annealed at 750 °C and 850 °C, a drop in ZFC magnetization and a small kink in FC magnetization observed around 245 K indicate the presence of a Morin transition (TM) from the α-Fe2O3 phase. Anisotropy constants were calculated for all the samples using the law of approach to saturation (LAS) method. The magnetocrystalline anisotropy energy distribution function for the NFO samples annealed at 750 °C and 850 °C exhibit broad peak due to the random distribution of spins associated with different particle size.

4-Fluoro-N-(4-hy-droxy-benzyl-idene)aniline.

In the title compound, C13H10FNO, the benzene ring planes are inclined at an angle of 50.52 (8)°. A characteristic of aromatic Schiff bases with N-aryl substituents is that the terminal phenyl rings are twisted relative to the plane of the HC=N link between them. In this case, the HC=N unit makes dihedral angles of 10.6 (2) and 40.5 (2)° with the hy-droxy-benzene and fluro-benzene rings, respectively. In the crystal, O-H⋯N and C-H⋯F hydrogen bonds lead to the formation of chains along the c- and b-axis directions, respectively. C-H⋯π contacts link mol-ecules along a and these contacts combine to generate a three-dimensional network with mol-ecules stacked along the b-axis direction.

(E)-N,N-Diethyl-4-{[(4-meth-oxy-phen-yl)imino]-meth-yl}aniline: crystal structure, Hirshfeld surface analysis and energy framework.

In the title benzyl-ideneaniline Schiff base, C18H22N2O, the aromatic rings are inclined to each other by 46.01 (6)°, while the Car-N= C-Car torsion angle is 176.9 (1)°. In the crystal, the only identifiable directional inter-action is a weak C-H⋯π hydrogen bond, which generates inversion dimers that stack along the a-axis direction.

Glycine-phthalic acid (1/1).

In the title compound, C2H5NO2·C8H6O4, the glycine mol-ecule exists as a zwitterion (2-aza-niumyl-ethano-ate) with a positively charged amino group and a negatively charged carboxyl-ate group. In the crystal, N-H⋯O and O-H⋯O hydrogen bonds link the components into layers parallel to the ab plane. The central part of each layer is composed of hydrogen-bonded glycine zwitterions, while phthalic acid mol-ecules inter-act with the zwitterions in such a way that benzene rings protrude up and down from the layer.

catena-Poly[[[aqua-(glycine-κO)lithium]-µ-glycine-κ(2) O:O'] bromide].

In the title coordination polymer, {[Li(C2H5NO2)2(H2O)]Br} n , the Li(+) cation is coordinated by three carboxyl-ate O atoms of zwitterionic glycine mol-ecules and by a water mol-ecule, forming a distorted tetra-hedral geometry. One of the two glycine mol-ecules bridges neighbouring complexes, forming an infinite chain parallel to the c axis. Polymeric chains are further linked by extensive hydrogen bonds involving the Br(-) anions and glycine and water mol-ecules, producing a three-dimensional network.

1-(2-Chloro-phen-yl)-3-(2-ethyl-hexa-noyl)thio-urea.

In the title compound, C15H21ClN2OS, the central chromophore moiety (C2N2OS) is approximately planar, with a maximum deviation of -0.027 (1) Å, and is oriented at a dihedral angle of 86.7 (1)° with respect to the chloro-phenyl ring. An intra-molecular N-H⋯O hydrogen bond stabilizes the mol-ecular conformation. In the crystal, mol-ecules associate via N-H⋯S hydrogen bonds, forming inversion dimers with motif R 2 (2)(8). These dimers are further connected by N-H⋯O hydrogen bonds, forming R 2 (2)(12) dimers. As a result, hydrogen-bonded chains running along [110] are formed. C-H⋯S inter-actions also occur. The terminal two C atoms of the butyl chain are disordered over two positions with an occupancy ratio of 0.54:0.46.

Synthesis, crystal structure and Hirshfeld surface analysis of the ortho-rhom-bic polymorph of 4-bromo-N-(4-bromo-benzyl-idene)aniline.

The crystal structure of the title compound, C13H9Br2N [systematic name: (E)-N,1-bis-(4-bromo-phen-yl)methanimine], is a second polymorph (Form II) crystallizing in the ortho-rhom-bic space group Pccn. The first polymorph (Form I) crystallizes in the monoclinic space group P21/c [Bernstein & Izak (1975 ▸). J. Cryst. Mol. Struct. 5, 257-266; Marin et al. (2013 ▸). J. Mol. Struct. 1049, 377-385]. The mol-ecule is disordered about an inversion center situated in the middle of the C=N bond, similar to the situation in the monoclinic polymorph: the C=N bond length is 1.243 (7) Å. In the crystal, mol-ecules stack along the b-axis direction and are linked by C-H⋯π inter-actions. The inter-atomic contacts in the crystal for both polymorphs were studied by Hirshfeld surface analysis and have notable differences. The solid-state fluorescence spectrum of Form II shows an emission peak at ca 469 nm. The two-photon absorption coefficient measured from the open aperture Z-scan technique is 1.3 × 10 -11 m W-1, hence, Form II shows optical limiting behaviour.

Syntheses, crystal structures, Hirshfeld surface analyses and energy frameworks of two 4-amino-anti-pyrine Schiff base compounds: (E)-4-{[4-(di-ethyl-amino)-benzyl-idene]amino}-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one and (E)-4-[(4-fluoro-benzyl-idene)amino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one.

The title Schiff base compounds, C22H26N4O (I) and C18H16FN3O (II), were each synthesized by a single-step condensation reaction. The substituted benzyl-idene ring is inclined to the pyrazole ring mean planes by 22.92 (7)° in I and 12.70 (9)° in II. The phenyl ring of the 4-amino-anti-pyrine unit is inclined to the pyrazole ring mean plane by 54.87 (7)° in I and by 60.44 (8)° in II. In the crystal of I, the mol-ecules are linked by C-H⋯O hydrogen bonds and C-H⋯π inter-actions to form layers lying parallel to (001). In the crystal of II, the mol-ecules are linked by C-H⋯O and C-H⋯F hydrogen bonds and C-H⋯π inter-actions, thereby forming layers lying parallel to (010). Hirshfeld surface analysis was employed to further qu-antify the inter-atomic inter-actions in the crystals of both compounds.

An in vivo comparison of hip structure analysis (HSA) with measurements obtained by QCT.

SUMMARY: In a population of elderly women, bone cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (Z), femoral neck axis length (FNAL), and width measured with hip structure analysis (HSA) on dual-energy x-ray absorptiometry (DXA) images in the femoral neck and trochanteric regions are highly correlated to quantitative computed tomography (QCT) measurements. INTRODUCTION: HSA is a method of obtaining measurements of proximal femur structure using 2D DXA technology. This study was designed to examine the correlations between HSA measurements and 3D QCT. METHODS: Forty-one women (mean age, 82.8 ± 2.5 years) were measured using DXA and a 64-slice CT scanner (1 mm slice thickness, 0.29 mm in plane resolution). HSA parameters were calculated at the narrow neck (NN) and trochanteric (IT) regions on the DXA image. These regions were then translated to anatomically equivalent regions on the QCT dataset by co-registering the DXA image and QCT dataset using four DXA images acquired at different angles. RESULTS: At the NN and IT regions, high linear correlations were measured between HSA and QCT for CSA r = 0.95 and 0.93, CSMI r = 0.94 and 0.93, and Z r = 0.93 and 0.89, respectively. All correlations were highly significant (p < 0.001), but there were differences in slope and offset between the two techniques, at least in part due to differences in calibration between the two techniques. FNAL and width of the bone at the NN and IT regions, physical measurements independent of the calibration, were highly correlated (r = 0.90-0.95, p < 0.001) and had slopes close to 1.0 (range, 0.978 to 1.003). CONCLUSION: CSA, CSMI, Z, FNAL, and width measured by HSA correlate highly to high-resolution QCT.

4-Bromo-N-(4-hy-droxy-benzyl-idene)-aniline.

In the title compound, C(13)H(10)BrNO, the benzene ring planes are inclined at an angle of 48.85 (17)°, resulting in a nonplanar mol-ecule. A characteristic of aromatic Schiff bases with N-aryl substituents is that the terminal phenyl rings are twisted relative to the HC=N plane. In this case, the HC=N unit makes dihedral angles of 11.1 (4) and 38.5 (3)° with the hy-droxy-benzene and bromo-benzene rings, respectively. In the crystal, the molecules are linked by O-H⋯N hydrogen bonds to form infinite (C8) chains along the b axis.

4-[(E)-(4-Methyl-phen-yl)imino-meth-yl]phenol.

In the title compound, C(14)H(13)NO, the two rings show significant deviation from coplanarity, with a dihedral angle between the two planes of 49.40 (5)°. The hy-droxy group is involved in an inter-molecular O-H⋯N hydrogen bond, forming an extended one-dimensional zigzag chain along (001).

Bis(tetra-ethyl-ammonium) bis-(hydrogen l-tartrate) l-tartaric acid monohydrate.

In the title compound, 2C(8)H(20)N(+)·2C(4)H(5)O(6) (-)·C(4)H(6)O(6)·H(2)O, the presence of the two tetra-ethyl-ammonium cations is balanced by two hydrogen l-tartrate anions. Also present in the asymmetric unit are a mol-ecule of l-tartaric acid and a water mol-ecule. The various components are linked by O-H⋯O hydrogen bonds. In the crystal, two-dimensional networks are formed via O-H⋯O hydrogen bonds and C-H⋯O inter-actions involving the water mol-ecule, the hydrogen l-tartrate anions and the l-tartaric acid mol-ecules. These layers, which stack along [001], are separated by tetra-ethyl-ammonium cations. The latter are also involved in C-H⋯O inter-actions with the anions and the l-tartaric acid and water mol-ecules participating in the two-dimensional network.

4-[2-(4-Meth-oxy-phen-yl)eth-yl]-3-(thio-phen-2-ylmeth-yl)-1H-1,2,4-triazol-5(4H)-one monohydrate.

In the title compound, C(16)H(17)N(3)O(2)S·H(2)O, the triazole ring makes a dihedral angle of 34.63 (6)° with the benzene ring. The thio-phene ring is disordered over two orientations [occupancy ratio = 0.634 (4):0.366 (4)] which make dihedral angles of 54.61 (16) and 54.57 (31)° with the triazole ring. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds stabilize the crystal structure.

3-[Chloro-(phen-yl)meth-yl]-6-methyl-1,2-benzoxazole.

The title compound, C(15)H(12)ClNO, is a functionalized 1,2-benzoxazole with a chloro-(phen-yl)methyl substituent. The mol-ecule is V-shaped, the dihedral angle between the mean plane of the 1,2-benzoxazole system [maximum deviation = 0.023 (3) Šfor the N atom] and the phenyl ring being 70.33 (14)°. There are no hydrogen-bonding inter-actions in the crystal structure, which is stabilized by van der Waals inter-actions only.

4-[3-(1H-Imidazol-1-yl)prop-yl]-3-methyl-5-(thio-phen-2-ylmeth-yl)-4H-1,2,4-triazole monohydrate.

In the title compound, C(14)H(17)N(5)S·H(2)O, the triazole ring makes dihedral angles of 48.15 (8) and 84.92 (8)° with the imidazole and thio-phenyl rings, respectively. The water mol-ecule is involved in inter-molecular O-H⋯N hydrogen bonding.

Crystal growth, structural, optical, mechanical and thermal properties of a new nonlinear optical single crystal: L-Ornithine monohydrochloride.

Amino acid family crystals exhibit excellent nonlinear optical and electro optical properties. l-Ornithine monohydrochloride single crystal, belongs to the amino acid group, was grown by the slow evaporation solution growth technique at room temperature. The grown crystals were characterized by single crystal and powder X-ray diffraction analysis, Fourier transform infrared (FTIR) spectroscopy, TGA, DTA and DSC analyses. UV-vis-NIR spectrum shows excellent transmission in the UV, visible and NIR region (300-1600nm). The mechanical properties of grown crystals were studied using Vickers microhardness tester. Its second harmonic generation efficiency was tested using Nd:YAG laser and is 1.25 times that of KDP.

Growth of ninhydrin single crystal and its characterization.

A novel organic nonlinear optical crystal ninhydrin having good optical quality was grown by solution technique using aqua solution. The quality of the crystal was also examined by high-resolution X-ray diffraction study. Solubility studies were made at different temperatures. Functional groups present in the grown material were identified from the vibrational frequencies of recorded FTIR spectrum. Transmittance of the crystal was recorded using the UV-vis-NIR spectrophotometer. From the thermal analysis it was observed that the material exhibits single sharp melting point. The fluorescence spectrum of ninhydrin was recorded. The Vicker's microhardness values were measured for the grown crystal. Second harmonic generation conversion efficiency estimated using Kurtz and Perry method is about five times that of KDP.

Growth, structural, optical and thermal properties of gamma-glycine crystal.

Single crystals of gamma-glycine were grown from a mixture of glycine, water and lithium bromide. Single crystal X-ray diffraction analysis confirmed the growth of gamma-glycine phase. Presence of various functional groups of gamma-glycine was identified by FTIR spectrum. Optical absorbance spectrum recorded in the wavelength range of UV-vis-NIR revealed that this crystal has good optical transparency in the range 250-1500 nm. Vickers microhardness values were estimated on the prominent (100) face. Thermogravimetric and differential scanning calorimetric analyses were carried out to study the thermal properties of gamma-glycine. Second harmonic generation efficiency of the crystal measured by Kurtz's powder method using Nd:YAG laser is about three times that of KDP.

Growth, structural, optical, thermal and mechanical properties of ammonium pentaborate single crystal.

Nonlinear optical single crystals of ammonium pentaborate (APB) were grown by the slow cooling method from aqueous solution. Grown crystal was characterized by powder X-ray diffraction (PXRD) and FT-IR spectral analysis. Perfection of the grown crystal was evaluated by high-resolution X-ray diffractometry (HRXRD). The effect of nylon threading on the perfection of the grown bigger crystal was also studied by HRXRD. The range and percentage of optical transmission was ascertained by recording UV-vis-NIR spectrum. Thermal properties were investigated by TG-DTA and DSC analyses. Its mechanical hardness was estimated by Vickers microhardness tester.

Growth and characterization of glycine picrate single crystal.

Glycine picrate (GP), an organic material, was synthesized and successfully grown by solution growth method. Cell parameters of the grown crystals were obtained from the single crystal X-ray diffraction analysis and the presence of functional groups was identified by FTIR study. Its optical properties were examined by UV-vis-NIR analysis, which shows that the crystal is transparent between the wavelengths 400 nm and 1000 nm. Thermal analysis carried out for the glycine picrate reveals that the crystal exhibits a single sharp weight loss at 214 degrees C. The fluorescence spectrum of glycine picrate was recorded. The Vicker's microhardness values were measured for the grown crystal.