Structural,spectroscopic properties and theoretical studies of (E)-1-(4-Bromophenyl)-3-(2,3,4-trimethoxyphenyl)prop-2-en-1-one as a potential anti-oxidant agent

The new chalcone compound namely (E)-1-(4-Bromophenyl)-3-(2,3,4-trimethoxyphenyl)prop-2-en-1-one (C₁₈H₁₇BrO₄) is crystallized in the monoclinic crystal system of P2₁/c space group. The unit cell dimensions are: a = 8.0753 (10) Å, b = 21.873 (3) Å, c = 9.3362 (12) Å, α = 90°, β = 99.369 (2), γ = 90° and Z = 4. The single crystal was grown using slow evaporation solution growth technique. The newly synthesized compound was characterized by using IR, ¹H- and ¹³C-NMR, UV-Vis and single crystal X-ray diffraction analyses. Quantum chemical method of Density Functional Theory (DFT) with B3LYP/6-311++G(d,p) has been employed to study the structural and spectral properties of the compound. The electronic absorption spectrum was calculated using the time dependent functional theory (TDDFT) method. The most stable conformer of the title chalcone is identified from the computational results. Hirshfeld surface analysis with fingerprint plots has been used as a graphical tool for visualization and understanding of intermolecular interactions. Intermolecular C?H····O interaction observed stabilize the crystal structure, forming an infinite one dimensional column. The effect of this intermolecular interaction in the solid state can be seen in the difference between the experimental and the theoretically optimized geometrical parameters. The crystal is transparent in the entire visible region and absorptive in the UV region. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron potential (MEP). The other molecular properties like charge transfer are explain using Mulliken population analysis. The antioxidant test indicated that the 2,3,4-trimethoxy substitution on the bromide chalcone to be one of the favorable modification to enhance its metal chelating activity.     

Crystal growth and characterization of Au3+ ion irradiated 2-amino-5-nitropyridinium hydrogen oxalate (2A5NPHO)

2-amino-5-nitropyridinium hydrogen oxalate (2A5NPHO) was grown using slow evaporation and bulk crystal of 2A5NPHO was harvested from Assembled Temperature Reduction (ATR) method. Cut and polished crystal was irradiated using Au³⁺ ion with various fluences. Electronic loss, nuclear energy loss and penetration depth were calculated using SRIM software. It was observed in X- ray pattern that intensity of peak was reduced. Intensity of peak decreased with increase of ion fluencies from 10¹³ ions/cm² to 10¹⁴ ions/cm². Optical properties were measured using UV-Vis spectrometer. The increase of absorption was due to excited electrons which were formed by vacancies and formation of additional defects centres. Energy band gap of irradiated crystals increased with increase of ion fluence. Energy band gap of irradiated crystals were 3.39 eV, 3.42 eV, and 3.4 eV for 10¹³ ions/cm², 5 × 10¹³ ions/cm² and 10¹⁴ ions/cm² respectively and increase of band gap was due to the increase of forbidden gap. Microhardness was calculated using Vicker's Hardness tester. Increase of microhardness in irradiation crystal was due to increase of high density lattice defects produced by Au³⁺ of 10.8 MeV. Electrical property was calculated using dielectric constant. Increase of dielectric constant was due to large polarization which caused by disorderness and rich defects in the crystalline surface. Decrease of intensity peak in fluorescence was due to transition of excited electron to intermediated energy levels from excited state which converted into vibrational energy of lattice atoms (phonon). Morphology of irradiated crystal was seen using scanning electron microscope (SEM). It was observed from the SEM image that surface of crystal was heavily damaged. It was also noticed that the thermal stability of the irradiated single crystal increased with increase of ion fluences. Impedance of irradiated crystal was measured. The bulk resistance and grain boundary resistance also were calculated.     

Separation of 4-aminobenzoic acid by cocrystallization: Crystal structure of the complex of 4-aminobenzoic acid with (2R,3R)-tartaric acid

4-Aminobenzoic acid (PABA) has been successfully separated from a mixture containing 2-aminobenzoic acid and (2R,3R)-tartaric acid. X-ray structure analysis confirms the separating result. The molecular complex formed by PABA and tartaric acid in 1:1 molar ratio crystallizes in the orthorhombic space group P2₁2₁2₁ with cell dimensions of a = 7.329(1) Å, b = 12.095(2) Å, c = 15.231(3) Å, V = 1350.1(4) ų, Z = 4. The crystal structure comprises protonated PABA, monoanion of tartaric acid, and crystalline water. The extensive H-bonding network exists in the crystal structure. H bonding between tartaric acid and both terminal groups on para position of PABA is considered as a possible reason for the successful separation.     

Synthesis,spectral, X-ray diffraction and DFT studies on 1-(2-methyl-2-propenyl)-3-(2,3,4,5,6-pentamethylbenzyl)benzimidazolium chloride hydrate

A new benzimidazole based N-heterocyclic carbene (NHC) salt (1) was synthesized by the reaction of benzimidazole precursor with alkyl halide. The structure of 1 was determined by elemental analysis, FT-IR, ¹H NMR and ¹³C NMR spectroscopy tecniques and X-ray crystallography. The compound crystallized in the triclinic space group P-1 with two molecules in the unit cell. The optimization of 1 was firstly performed at B3LYP/6-311G++(d,p) level, then the theoretical spectral studies performed and compared with the experimental values. Besides the frontier molecular orbital energies and chemical reactivity analysis of 1, together with the electrostatic potential and molecular electrostatic potential analyses were performed at the same level of theory.     

不同晶体结构Gd2(MoO4)3:Eu3+荧光粉的合成及其发光性能研究

采用溶胶凝胶-燃烧法,柠檬酸为络合剂合成出系列Gd₂(MoO₄)₃:Eu³⁺荧光粉.利用X射线衍射(XRD)、扫描电子显微镜(SEM)和荧光光谱对样品的结构、形貌和发光性能进行了研究.XRD分析表明:稀土离子与柠檬酸为1:0.5时,800℃热处理获得单斜结构的Gd₂(MoO₄)₃:Eu³⁺荧光粉.单斜结构的Gd₂(MoO₄)₃:Eu³⁺荧光粉到正交结构的Gd₂(MoO₄)₃:Eu³⁺荧光粉的转换可以通过改变稀土离子与柠檬酸摩尔比和热处理温度等合成条件实现.Gd₂(MoO₄)₃:Eu³⁺荧光粉的形貌受合成条件的影响.荧光光谱研究表明:Gd₂(MoO₄)₃:Eu³⁺荧光粉的主发射峰位于616 nm处来自于Eu³⁺的⁵D₀→⁷F₂电偶极跃迁.正交结构的Gd₂(MoO₄)₃:Eu³⁺荧光粉发射强度明显高于单斜结构的荧光粉.计算⁵D₀→⁷F₂与⁵D₀→⁷F₁跃迁发射的相对强度比值表明:正交结构的Gd₂(MoO₄)₃:Eu³⁺中Eu³⁺局域环境的对称性较高。     

Synthesis and crystal structures of 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran

The title compounds 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline 1 (C₁₉H₁₂ClN₃O, M _r = 333.77) and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran 2 were synthesized and crystallized. The crystals of compound 1 are triclinic, space group P-1, a = 7.488(2), b = 9.127(3), c = 12.252(3) Å, = 73.58(2), = 78.38(2)°, = 75.39(2), Z = 2, V = 769.5(4) ų; The compound 2 crystallizes in space group P2₁/n, with cell parameters a = 13.582(2), b = 8.974(1), c = 16.960(2) Å, = 103.34(1)° and D _calc = 1.352 g/cm^–3 for Z = 4. X-ray analysis reveals that atoms C(1)—C(5) and O form a pyran ring in compound 1, which adopts half-chair conformation. In compound 2 the atoms C(12)—C(16) and O form a pyran ring which adopts boat conformation, another six-membered ring (C(8)—C(13)) adopts a half-chair conformation. In addition, there are intermolecular hydrogen bonds in the crystal structures 1 and 2.     

Synthesis and Crystal Structure of One-Dimensional Carboxylate-Bridged Copper(II) Complex with 2-Pyridylmethylamino-3-butyric acid

Abstract The tridentate Schiff base carboxylate-containing ligand 2-pyridylmethylamino-3-butyric acid (Hpaba) reacts with copper(II) perchlorate to give the one-dimensional chain complex {[Cu(μ-paba)](ClO₄)·H₂O} _n (1). The coordination geometry of each copper(II) ion is best described as a square-plane with two nitrogen atoms and one carboxylate oxygen atom of the ligand, and one carboxylate oxygen atom belong to another ligand. It crystallizes in the monoclinic system P2₁/c with a = 12.717(2), b = 7.9163(15), c = 14.981(2) ?, β = 111.14(1)°, V = 1406.8(4) ?³, Z = 4. Cyclic voltammogram of 1 undergoes the reversible one-electron oxidation to the Cu(III) and the reversible one-electron reduction to the Cu(I) state. Graphical Abstract Crystal structure of 1 reveals a syn-anti carboxylate-bridged one dimensional chain complex in which the coordination environment around each copper(II) ion exhibits a distorted square plane.      

Synthesis, characterization, peripheral studies, and structural analysis of E-4-(N-methylanilino)-3-pentene-2-one, C12H15NO

Crystallographic structural refinement of E-4-(N-methylanilino)-3-pentene-2-one (I) has been carried out by means of three-dimensional single-crystal X-ray diffractometry. The title compound crystallizes in space group C2 (No. 5,Z = 4). The lattice constants are a = 21.543(4), b = 6.433(1), c = 8.019(2) Å, and = 97.82(3)°. Characterizations include physical property determinations and spectrometric identifications employing IR, ¹H and ¹³C NMR, and X-ray powder analyses. The molecules in the crystal lattice are held together by van der Waals forces. Selected bond distances and angles are presented and discussed as well as synthesis and peripheral studies.     

以2-甲基-丙烯酸,4-(吡啶-4-偶氮)-苯酯为配体的四个配位化合物的合成、晶体结构和紫外吸收

4个单核配位化合物,[Zn(Maape)2(H2O)2(NO3)2] (1, 单核), [Cu(Maape)2(H2O)2(NO3)2] (2, 单核), [Zn(Maape)2Cl2] (3, 单核), [Zn(Maape)(H2O)4SO4] (4, 单核),都是用过渡金属盐和配体2-甲基-丙烯酸,4-(吡啶-4-偶氮)-苯酯合成的.四个化合物由单晶X-射线衍射和结构分析表明都是单核化合物.另外,还通过红外和元素分析对其进行表征.配位化合物的结构不仅受配位金属离子的影响还受不同配位阴离子的影响.化合物1和2的结构都是由一个金属离子中心、2个配位硝酸根离子和2个配体分子组成的单核配合物.化合物3的单核结构中包含一个Zn(II)、2个氯离子和2个配体分子.而化合物4的不对称单元[Zn(Maape)(H2O)4SO4]中Zn(II)中心位于二重对称轴上.在本文中,配体和4个化合物都在323 nm处有最高紫外吸收峰.     

Nd3+:LiLa(MoO4)2晶体生长、光谱和激光特性

本论文报道了Nd3+:LiLa(MoO4)2晶体生长、光谱和激光特性.采用提拉法生长出尺寸为φ20×34mm3的Nd+3+:LiLa(MoO4)2晶体.应用Judd-Ofelt理论计算了Nd3+离子在Nd3+:LiLa(MoO4)2晶体中唯象强度、自发发射跃迁几率、荧光分支比、辐射跃迁寿命和荧光量子效率.Nd3+:LiLa(MoO4)2晶体的偏振吸收跃迁截面分别为9.52×10-20cm2(π-偏振)和4.46×10-20cm2(σ-偏振).它的偏振发射跃迁截面分别为0.67×10-19cm2(σ-偏振)和1.02×10-19cm2(σ-偏振).在氙灯泵浦下,获得74.4mJ的1.06μm的激光输出,激光阈值为0.676J,激光总效率和斜率效率分别为0.39;和0.48;.     

Preparation and characterization of a bidentate carboxylate-bridged dinuclear cadmium(II) complex with bis(2-pyridylmethyl)amino-3-propionic acid

The carboxylate-bridged dinuclear complex [Cd(-pmpa)(H₂O)](ClO₄)·H₂O (1) (Hpmpa = bis(2-pyridylmethyl)amino-3-propionic acid) has been synthesized and structurally characterized by X-ray diffraction method. It crystallizes in the monoclinic system P2 ₁/n with a = 7.9678(6) Å, b = 17.5103(9) Å, c = 14.3147(9) Å, = 94.1030(10)°, V = 1992.0(2) ų, Z = 4. The carboxylate group of the pmpa ligand adopts a bidentate bridging coordination mode, and the ligand acts as -bridge linking two cadmium(II) ions to form a dinuclear complex. Each cadmium atom is seven-coordinate, with a distorted pentagonal bipyramidal geometry. The cyclic voltammogram of 1 undergoes irreversible one-electron oxidation to the Cd(III) and reversible one-electron reduction to the Cd(I).     

Synthesis and X-ray structural investigations of 2-amino-7-methyl-4-(1-naphthyl)-5-oxo4H,5H-pyrano[4,3-b]pyran-3-carbonitrile and 2-amino-4-(1-naphthyl)-5-oxo-4H,5Hpyrano[3,2-c]chromene-3-carbonitrile

Synthesis and X-ray structural investigations have been carried out for the two title compounds C₂₀H₁₄N₂O₃ (4) and C₂₃H₁₄N₂O₃⋅C₂H₃N (5). Compound 4 crystallizes in the monoclinic space group P2₁/n, with a = 7.0542(5), b = 8.822(1), c = 24.833(2) ?, β = 94.30(4)^∘, V = 1541.0(4) ?³, and Z = 4. Compound 5 crystallizes with an acetonitrile solvent molecule in the monoclinic space group P2₁/n, with a = 11.075(1), b = 7.854(1), c = 22.703(2) ?, β = 90.67(1)^∘, V = 1974.5(3) ?³, and Z = 4. In both molecules, the 4H-pyran ring adopts a flattened-boat conformation. The naphthalene substituent occupies a pseudo-axial position and the dihedral angle with the flat part of the pyran ring is equal to 94.6(3) in 4 and 76.8(3)^∘ in 5. The mutual orientation of these fragments and the flatness of the heterocyclic rings lead to H⋅sH intramolecular steric interactions: H4A⋅sH18A 1.98 ? in 4 and 2.11 ? in 5. In the crystal of 4, intermolecular hydrogen bonds N–H⋅sO and C–H⋅sN link molecules into infinite tapes along the b axis. In the crystals of 5, intermolecular hydrogen bonds N–H⋅sO and C–H⋅sN link molecules into infinite layers parallel to the bc plane. In each case, the C–H⋅sN interaction can be considered to be a weak hydrogen bond. The acetonitrile molecules link via intermolecular weak C–H⋅sN hydrogen bonds to form infinite chains along the b axes.     

The utility of 4-aminobenzoic acid in promotion of hydrogen bonding in crystallization processes: the structures of the cocrystals with halo and nitro subsituted aromatic compounds, and the crystal structures of the adducts with 4-nitroaniline (1:1), 4-(4-nitrobenzyl)pyridine (1:2), and (4-nitrophenyl)acetic acid (1:1)

A number of molecular adducts of 4-aminobenzoic acid (4-ABA) have been prepared and characterized using infrared spectroscopy and in three cases by X-ray diffration methods. These three compounds are with 4-nitroaniline [(4-ABA) (C₆H₆N₂O₂)], 4-(4-nitrobenzyl) pyridine, [(4-ABA)₂(C₁₂H₁₀N₂O₂)₄], and (4-nitrophenyl)acetic acid, [(4-ABA) (C₈H₇NO₄)]. Other compounds described are with 4-chlorobenzoic acid, [(4-ABA) (C₇H₅ClO₂)], 4-bromobenzoic acid, [(4-ABA) (C₇H₅BrO₂)], 4-cyanobenzoic acid, [(4-ABA) (C₇H₆N₂)], 2-nitrobenzoic acid, [(4-ABA) (C₇H₅NO₄)], and 3-nitrobenzoic acid, [(4-ABA) (C₇H₅NO₄)]. All compounds have 1:1 stoichiometry except that with 4-(4-nitrobenzyl)pyridine (1:2) which is unique in being retro-stoichiometric. A review of the systematics of the 4-aminobenzoic acid adducts is also made, particularly with respect to the infrared characterization of the cocrystalline materials and prediction of their NLO potential.     

Synthesis,characterization and impedance spectroscopy of the new material [(CH3) (C6H5) 3P] 2CoBr4: a member of the A2BX4 family

The crystal structure of bis‐(methyltriphenylphosphonium) tetrabromocobaltate (II), [(C₁₉H₁₈P)₂ CoBr₄] is determined: M_r = 933.203, monoclinic, P2₁, a = 9. 6977 (3) Å, b = 12.5547 (4)Å, c = 16.4503 (6)Å, β = 105.603 (2)°, V = 1929.04 (11)ų, Z = 2, D_x = 1.607 Mg m^‐3, T = 298 K. Differential thermal analysis at high temperatures shows three endothermic peaks characterizing four phases, with onset temperatures at T₁= 313±2 K, T₂ = 320±4 K and T₃= 360±1 K. The structural instability detected via the temperature dependence of permittivity at T₁ is ascribed to order‐disorder transition associated with cation dipole reorientation. Permittivity and ac conductivity studies as a function of temperature (295 K‐375 K) and frequency (0.11 kHz < f <100 kHz) are presented. The results indicate the importance of the cation size and shape on the phase transitions in the system. Bulk conductivity behavior is thermally activated. The associated activation energies are in the range 2.9 to 1.0 eV depending on the temperature regime. Two contributions to the ac conductivity, one dominating at low temperatures and high frequencies which are characterized by superlinear frequency exponent and the second dominates at high temperatures characterized by a sublinear frequency exponent. The behavior is interpreted in terms of the jump relaxation model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The synthesis and crystal structure of (4<Emphasis Type="Italic">E</Emphasis>)-5(3-chlorophenyl)-<Emphasis Type="Italic">N</Emphasis>-(4-chlorophenyl)-2-diazo3-oxopent-4-enoic acid amide

(4E)-5-(3-Chlorophenyl)-N-(4-chlorophenyl)-2-diazo-3-oxopent-4-enoic acid amide (5) was synthesized from p-chloroaniline to N-(4-chlorophenyl)-2-diazo-3-oxo-butyramide (4) with 3-chlorobenzaldehyde. The yielded product 5 was investigated with X-ray crystallographic, NMR, MS, and IR techniques. Compound 5 (C₁₇H₁₁Cl₂N₃O₂, Formula wt = 360.19), crystallizes in the monoclinic space group P21/c with unit cell parameters a = 10.516(2), b = 17.996(4), c = 8.902(2) Å, α = 90.00, β = 105.36(3), γ = 90.00^°. V = 1624.5(6) ų, Z = 4, D _x = 1.473 Mg m^?3. The final R was 0.0511.     

Synthesis and structural analysis of Bis(2-hydroxyphenyl) phenylamine, PhN(o-C6H4OH)2: Comparison with Tris(2-hydroxyphenyl)amine N(o-C6H4OH)3

The molecular structures of N(o-C₆H₄OH)₃, PhN(o-C₆H₄OH)₂, andp-TolN(o-C₆H₄OMe)₂ have been determined by X-ray diffraction, thereby indicating several structural differences. For example, whereas the nitrogen in N(o-C₆H₄OH)₃ is pyramidal with Σ_C–N–C = 348.3^∘, the nitrogen atoms in PhN(o-C₆H₄OH)₂ andp-TolN(o-C₆H₄OMe)₂ are trigonal planar with Σ_C–N–C = 359.9^∘ and Σ_C–N–C = 360.0^∘, respectively. The phenyl andp-tolyl groups of PhN(o-C₆H₄OH)₂ andp-TolN(o-C₆H₄OMe)₂ lie close to the trigonal plane, while theo-C₆H₄OH ando-C₆H₄OMe groups are almost orthogonal to this plane. The coplanar and orthogonal orientations of the aryl groups of PhN(o-C₆H₄OH)₂ andp-TolN(o-C₆H₄OMe)₂ are in marked contrast to those of the phenyl groups within Ph₃N, which exhibit dihedral angles in the range 38–52^∘ and approximateD₃ symmetry. The observed structures of PhN(o-C₆H₄OH)₂ andp-TolN(o-C₆H₄OMe)₂ may be rationalized in terms of maximizing delocalization of the nitrogen lone pair into the phenyl andp-tolyl groups, while minimizing unfavorable overlap with theo-C₆H₄OH ando-C₆H₄OMe groups due to the presence of π-donatingortho-substituents; the orthogonal orientation of theo-C₆H₄OH ando-C₆H₄OMe groups is also one that minimizes unfavorable steric interactions between theortho-substituents.     

Synthesis,characterization and crystal structure of a novel Ni(II) coordination polymer with dipyrido[3,2‐a:2′,3′‐c]phenazine and 4,4′‐oxy(bisbenzoate)

A novel coordination polymer, [Ni(dppz)(oba)(H₂O)]·0.5H₂O (dppz = dipyrido[3,2‐a:2′,3′‐c]phenazine and oba = 4,4′‐oxy(bisbenzoate)) has been synthesized through hydrothermal method and characterized by IR, and single‐crystal X‐ray diffraction. It crystallizes in monoclinic, space group C2/c with a = 23.163(5), b = 18.211(4), c = 14.460(3) Å, α = γ = 90°, β = 100.45(3)°, V = 5998(2) ų, Z = 2. The structure was solved by direct methods and refined to R = 0.0866 (wR₂ = 0.1836). The compound exhibits interesting one‐dimensional chain structures, which are further stacked through π‐π interactions to form supramolecular double chains. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)