Molecular and crystal structure of 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen -2-yl)butane-1,3-dione

Single crystal X-ray diffraction is used to determine the crystal and molecular structure of 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen-2-yl)butane-1,3-dione. Crystallographic data for C₁₄H₈F₄N₂O₂S are as follows: a = 8.2723(6) ?, b = 9.3009(7) ?, c = 9.9895(7) ?; α = 79.224(2)°, β = 75.851(2)°, γ = 72.337(2)°. Triclinic crystal system, P-1 space group, d _x = 1.622 g/cm³, V = 704.83(9) ?³, μ = 0.286 mm⁻¹, crystal size 0.30×0.20×0.20 mm, R1 = 0.0891, wR2 = 0.1989.     

1-[4-(二甲氨基)苯亚甲基氨基]-4-苯基硫脲的另一个手性对映体晶体结构

对-二甲氨基苯甲醛和苯基氨基硫脲缩合反应生成1-[4-(二甲氨基)苯亚甲基氨基]-4-苯基硫脲(DMB), 产物能从溶液中析出单一手性对映体晶体. 用单晶X射线衍射技术测定了它的绝对构型, 晶体属正交晶系, P2₁2₁2₁空间群, a＝0.7870(2) nm, b＝1.1560(2) nm, c＝1.6668(3) nm, V＝1.5164(5) nm³, Z＝4, D_c＝1.307 g/cm³, F(000)＝632, μ＝0.213 mm^－1, 2557个可观测点[I＞2s(I)]精修的最终残差因子: R＝0.0409, wR＝0.1061, Flack参数为0.00(9), 能够确定绝对构型. 化合物的晶体结构和大宗粉末样品的固体圆二色谱表明化合物在结晶过程中发生单一对映体的手性堆积.     

The Raman spectrum of tetragonal Eu3+CaF2

The Raman spectrum of a tetragonal single crystal of the compound Eu_xCa_1-(3/2)x F₂(where x = 0.002) is reported. The main features of the spectrum are the ⁷F₀ - ⁷F₁ and ⁷F₀ → ⁷F₂ electronic transitions of Eu³⁺ ions located at a site of C₂ symmetry and vibrational transitions which involve movements of the europium ion. The characteristic phonon band of cubic CaF₂ is for the rare-earth doped crystal moved to a higher frequency and the corresponding Raman tensor is that for a crystal of tetragonal symmetry.     

Synthesis and characterisation of star-shaped liquid crystalline polymer with a POSS core

The star-shaped POSS-graft-LCP with POSS as the core and liquid crystal polymer, poly{6-(4?-octyloxyphenyl-4″-benzoyl)hexyl acrylate}, as arms was prepared by atom transfer radical polymerisation technique using octa(3-chloropropyl) polyhedral oligomeric silsesquioxane [POSS-(CH₂CH₂CH₂Cl)₈] as initiator. For comparison, the linear liquid crystal polymer, poly{6-(4?-octyloxyphenyl-4″-benzoyl)hexyl acrylate} (LLCP), was obtained by conventional radical polymerisation. Both liquid crystal polymers were characterised by FT-IR, ¹H NMR, ¹³C NMR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarised optical microscopy and X-ray diffraction analysis. The liquid crystal phase behaviour research demonstrated that both liquid crystal polymers were reversible thermotropic nematic liquid crystal materials. The number of polymerisation degree of every arm attached on POSS in POSS-graft-LCP impacted greatly on the liquid crystal properties and only a small one was necessary for it to exhibit a broad liquid crystal range. Results further demonstrated that the special star-shaped topology of POSS and the eight arms attached helped POSS-graft-LCP form and stabilise liquid crystal phase easily. This research may further expand the way to star-shaped LCPs by employing a variety of (meth)acrylate and other vinyl liquid crystalline monomers.     

Synthesis and crystal structure of 2-{5-[2-(2,6-dichlorophenylamino)benzyl]-4-p-tolyl-4H-1,2,4-triazol-3-ylthio}acetate

The compound 2-{5-[2-(2,6-dichlorophenylamino)benzyl]-4-p-tolyl-4H-1,2,4-triazol-3-ylthio}acetate has been prepared and characterized by IR, ¹H NMR, ¹³C NMR and mass spectra. The crystal and molecular structure were further confirmed using single crystal X-ray diffraction. The crystal structure has been found to be stabilized by intermolecular C–H···O interaction generating bifurcated hydrogen bonds whereas the C–H···N interactions generate chain of molecules. The intramolecular N–H···N hydrogen bond forms a ring with S(7) graph-set motif.     

Phosphorinane and Enol Rings in One Molecule. Evidence for Reciprocal Stabilization of Half-Chair Conformations

Abstract.

The X-ray crystal structure of 2-(2′,4′-dioxo-3′-pentyl)-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (2) reveals significant half-chair distortion of the axially oriented cisenol ring. The molecule also undergoes in-plane deformations. R(O...O) = 2.410 Å in the enol moiety indicates a very strong hydrogen bonding. The enol content, δ_OH and thermodynamic parameters for the axial-equatorial conformational and keto-enol equilibriums were obtained from ¹H, ³¹P NMR and IR measurements in comparison with the planar 4,6-dimethyl isomer (1) containing equatorially oriented enol ring. The X-ray single crystal structure of 5,5-dimethyl-2-(methoxycarbonyl-3′-oxo-2′-butyl)-2-oxo-1,3,2-dioxaphosphorinane (3) reveals the unusual half-chair conformation of the dioxaphosphorinane cycle disposed a trans-enol ring substituent. ¹H, ³¹P NMR and IR solution data support the same structure displays a strong conformational preference while the minor forms are chair conformers with an axial or equatorial cis-enol ring.     

Ion-selective and complexation properties, vibrational spectra, and crystal and molecular structure of 1,5-bis[2-(hydroxyethoxyphosphoryl)phenoxy]-3-oxapentane

The ion-selective properties of 1,5-bis[2-(hydroxyethoxyphosphoryl)phenoxy]-3-oxapentane H₂R² have been described. The molecular and crystal structure of H₂R² has been determined by powder X-ray crystallography and IR spectroscopy. The molecule has the twofold symmetry axis, orthorhombic crystal system, space group Pbcn, a = 16.830(2) ?, b = 8.866(15) ?, c = 15.7190(2) ?, V = 2346.1(6) ?³, Z = 4. A new CuR² · 2H₂O complex has been synthesized and characterized.     

Solubility of thioindigo dopants in a smectic liquid crystal host evaluated by 2H NMR spectroscopy

The solubility of two partially deuterated thioindigo dopants in a smectic liquid crystal host was evaluated by variable temperature ²H NMR spectroscopy and polarized microscopy. 2H NMR spectra showed that the dopant (±)-6,6'-bis(2-octyloxy)-5,5-dinitrothioindigo-d ₆ forms a homogeneous solution with the smectic phases of the liquid crystal host (±)-4-(4-methylhexyloxy)phenyl 4-decyloxybenzoate (PhB) up to its saturation point of 3 mol %. These results are consistent with polarized microscopy observations of the dopant crystallizing out of solution upon reaching a concentration of 3 mol %. On the other hand, ²H NMR spectra of (±)-5,5'-dichloro-6,6'-bis(2-octyloxy)thioindigo-d ₆ dissolved in PhB showed evidence of a partitioning of the solution between smectic and isotropic microdomains, which increases with increasing dopant concentration—from 1.2 to 9.1 mol %. To a large extent, this smectic/isotropic microphase separation could not be detected by polarized microscopy. These results suggest that ²H NMR spectroscopy can provide a more accurate determination of the occurrence and extent of microphase separation in doped liquid crystal samples.     

Synthesis and characterization of new thiadiazole derivatives bearing a pyrazole moiety

A series of thidiazole derivatives (4, 7) from pyrazole-3-carboxylic acid chloride (2) and pyrazole-3,4-dicarboxylic acid chloride derivatives (6) were synthesized and characterized. The structures of the new compounds were confirmed byelemental analysis, NMR (¹H and ¹³C) and IR spectra. The molecular and crystal structure of 4-benzoyl-N-[5-(methylthio)-1,3,4-thiadiazol-2-yl]-1,5-di-phenyl-1H-pyrazole-3-carboxamide(4d)was determined by single crystal X-ray diffraction method.     

Preparation,Structural Characterization and the Molecular Structure of 2,3,5-Trinitro-<Emphasis Type="Italic">p</Emphasis>-xylene

2,3,5-trinitro-p-xylene (TPX) is synthesized by nitration of p-xylene in mixed acid of nitric and sulfuric acid. Single crystal of TPX is cultured from DMF solution using a slow cooling method. The compound is characterized by FT-IR, ¹H NMR and MS techniques. The crystal structure is determined by X-ray⁴ single-crystal diffraction analysis. The crystal belongs to the monoclinic system with space group P_n. Its unit cell parameters are as follows: a = 0.8271(2), b = 0.6011(1), c = 1.0487(2) nm, β = 105.42(2)^∘, V = 0.50263(2) nm³, D_c = 1.593 g/cm³, Z = 2, F(0 0 0) = 248. The molecular structures of TPX have been calculated at the B3LYP/6-31G^** and B3LYP/6-311G^** levels of theory, and its frequencies analysis have also been accomplished at the same level of theory. The thermal decomposition process of the compound was studied using DSC and TG-DTG techniques. The predicted nitro group vibrations with B3LYP/6-311G^** calculation considerably agree with the observed frequencies. The calculated results propose that the structural parameters from the theory are close to those of the crystal structure from the experiments.     

Synthesis and structure of (η-cyclopentadienyl)(η-(1-(η-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel - the first analogue of nickelocene with a nickelacyclopentadienyl ring

A new metallacyclic compound (η⁵-cyclopentadienyl)(η⁵-(1-(η⁵-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel was synthesised and characterised. Its molecular and crystal structure was determined by X-ray measurements. It crystallises from hexane:THF mixture in the monoclinic crystal system and the P2₁/c space group. This is the first example of the homometallic metallametallocene of nickel. Like in nickelocene the central nickel atom has 20 valence electrons, so the compound can be regarded as the first nickelacyclic analogue of nickelocene.     

Influence of protonation on the geometry of 2-{[(2,6-dimethylphenoxy)ethyl]amino}-1-phenylethan-1-ol: crystal structures of the free base and of its chloride and 3-hydroxybenzoate salt forms

The aroxyalkylaminoalcohol derivatives are a group of compounds known for their pharmacological action. The crystal structures of four new xylenoxyaminoalcohol derivatives having anticonvulsant activity are reported, namely, 2-{[2-(2,6-dimethylphenoxy)ethyl]amino}-1-phenylethan-1-ol, C₁₈H₂₃NO₂, 1 , the salt N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxy-1-phenylethan-2-aminium 3-hydroxybenzoate, C₁₈H₂₄NO₂⁺·C₇H₅O₃^?, 2 , and two polymorphs of the salt (R)-N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxy-1-phenylethan-2-aminium chloride, C₁₈H₂₄NO₂⁺·Cl^?, 3 and 3p . Both polymorphs crystallize in the space group P2₁2₁2 and each has two cations and two anions in the asymmetric unit (Z′ = 2). The molecules in the polymorphs show differences in their molecular conformations and intermolecular interactions. The crystal packing of neutral 1 is dominated by intermolecular O—H…N hydrogen bonds, resulting in the formation of one-dimensional chains. In the crystal structures of the salt forms ( 2 , 3 and 3p ), each protonated N atom is engaged in a charge-assisted hydrogen bond with the corresponding anion. The protonation of the N atom also influences the conformation of the molecular linker between the two aromatic rings and changes the orientation of the rings. The crystal packing of the salt forms is dominated by intermolecular O—H…O hydrogen bonds, resulting in the creation of chains and rings. Structural studies have been enriched by the calculation of Hirshfeld surfaces and the corresponding fingerprint plots.     

Synthesis,structure and spectroscopic properties of CuL(MeOH), H2L = (E)-N 1-(2-((2-aminocyclohexydiimino)(phenyl)methyl)-4-chlorophenyl)-N 2-(2-benzyl-4-chlorophenyl)oxalamide

A new kind of copper(II) complex, CuL(MeOH) (H₂L?=?(E)-N ¹-(2-((2-aminocyclohexydiimino)(phenyl)methyl)-4-chlorophenyl)-N ²-(2-benzyl-4-chlorophenyl)oxalamide) has been synthesized and its structure determined by single-crystal X-ray methods. Copper(II) ion is five-coordinate, bonding to four nitrogen atoms from H₂L and one oxygen atom from MeOH. Hydrogen bonds in the crystal result in the formation of a one-dimensional structure. EPR spectra are discussed. Computer simulation gave g_||?=?2.200, g_⊥?=?2.002. On the basis of the synthesis and the crystal structure, the mechanism of the metal template reaction involved in the formation of the complex was verified.     

Crystal structure of a new compound C17H22FN3O32+·ZnCl42-

A new compound C₁₇H₂₂FN₃O₃ ²⁺ ZnCl₄ ² (pefloxacindium tetrachlorozincate(II)), C₁₇H₂₀FN₃O₃ 1-ethyl-N-methyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methyl-1-piperazinyl)-3-quinoline carbonic acid (PefH, pefloxacin) is synthesized, and its crystal structure is determined. The crystal contains PefH₃ ²⁺ and ZnCl₄ ²⁻ ions. The supramolecular architecture of the crystal is analyzed.     

Synthesis and characterization of a novel η 2-iminoacyl monocyclopentadienyl titanium(IV) complex

An unusual complex, [CpTi(η²-(C,N)-2-ArNH–C₆H₄C=NAr)Cl₂] (Ar?=?2,6- ⁱ Pr₂C₆H₃) (1) has been synthesized and characterized by elemental analysis, NMR spectra, and single crystal X-ray diffraction. The ¹³C NMR resonance of the imine carbon atom of 1 at δ?221?ppm is consistent with the η²-(C,N) binding. This was confirmed by single crystal X-ray diffraction study of 1. In the complex, Ti atom is five-coordinate with a η²-bound iminoacyl ligand and one Cp ligand occupying the axial position in a distorted square pyramid.     

Synthesis,spectroscopic and thermal properties of Pt(II) complexes of some polydentate ligands

The new tetradentate symmetrical (2R,2′S)-1,1′-piperazine-1,4-diyldipropane-2-thiol) (L¹), (2S)-1-[bis(2-aminoethyl)amino]propan-2-ol) (L²), and 2-{(E)-[((1R,2S)-2-{[(1Z)-(2-hydroxy phenyl)methylene]amino}cyclohexyl)imino]methyl}phenol (L³) ligands were synthesized and characterized on the basis of FT-IR, ¹H, ¹³C NMR, EI mass, and elemental analysis. Three commercially available ligands, (2,2′-[ethane-1,2-diylbis(thio)]diethanol (L⁴), 2,2′-dithiodiethanenamine (L⁵), and (2,2′-[ethane-1,2-diyldi(imino)] diethanol (L⁶), were also studied. Pt(II) complexes were characterized by FTIR, elemental analysis and thermal methods. Thermal behaviors of these complexes were investigated in the range 10–1000 °C. Magnetic properties were also studied, and the all complexes were found to be diamagnetic. The structures consist of the monomeric units in which the Pt(II) atoms exhibit square planar geometry. N,N′-bis(salicylidene)-1,2-cyclohexane has been synthesized and characterized by X-ray single crystal diffraction measurement. The ligand crystallizes in monoclinic crystal system and space group, Cc.     

Extraction—spectrophotometric determination of nickel with 4-chloro-2-nitroso-1-naphthol and crystal violet

Six nitrosonaphthol derivatives are evaluated for the determination of nickel(II) after ion-pair formation with zephiramine or crystal violet, 4-chloro-2-nitroso-1-naphthol is the best; its nickel complex forms an extractable pair with crystal violet. The apparent molar absorptivity is 8.2 × 10⁴ l mol^-1 cm^-1 at 611 nm; calibration graphs are linear in the range 0–10^-5 M nickel(II).     

Synthesis and structure of C17H22FN3O 32+ ?CuCl 42-

A new compound C₁₇H₂₂FN₃O₃ ²⁺ • CuCl₄ ^2- [pefloxacindium tetrachlorocuprate(II)], C₁₇H₂₀FN₃O₃ — 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methyl-1-piperazinyl)-3-quinoline carboxylic acid (pefloxacin, PefH) is synthesized and characterized by single crystal X-ray diffraction technique. The crystal structure of the compound contains one PefH₃ ²⁺ cation and one CuCl₄ ^2- anion. The supramolecular architecture of the crystal is determined.     

Six coordinate Ni(II) complexes of ONN donor aroylhydrazone ligands: synthesis,spectral studies,and crystal structures

A new ligand N′-(pyridin-2-ylmethylene)nicotinohydrazide (HL²) and two Ni(II) complexes of stoichiometry NiL¹·H₂O [L¹-2-benzoylpyridine nicotinoylhydrazone] and NiL²·H₂O have been synthesized and characterized by elemental analyses, IR and UV–Vis spectral studies. Structures of HL² and Ni(II) compounds have been determined by single crystal X-ray diffraction studies which reveal a distorted octahedral geometry around the two Ni(II) centers.

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Graphical abstract A new ligand N￠-(pyridin-2-ylmethylene)nicotinohydrazide (HL2) and two Ni(II) complexes of stoichiometry NiL1·H2O [L1-2-benzoylpyridine nicotinoylhydrazone] and NiL2·H2O have been synthesized and characterized by elemental analyses, IR, UV–Vis spectral studies and single crystal X-ray analysis.

     

Influence of the central metal on the crystal structures and electronic structures of biferrocene trinuclear complexes

Five metal-bridged biferrocene complexes of the Schiff-base ligand (HL = S-benzyl-N-(ferrocenyl-1-methyl-methylidene)dithiocarbazate) have been studied by single crystal X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy. The crystal structures of the complexes show that the central metal ions are tetra-coordinated by two ligands in two modes: the central d⁸ transition metal ions (Ni²⁺, Pd²⁺, and Pt²⁺) are nearly square-planar coordinated and the d¹⁰ transition metal ions (Zn²⁺ and Cd²⁺) are tetrahedrally coordinated. Interestingly, the isomer shifts in ⁵⁷Fe Mössbauer spectroscopy are also of two kinds: d⁸ transition metal ions (0.097-0.247 mm/s) and d¹⁰ transition metal ions (0.416-0.435 mm/s).