Crystal growth,spectral characterization and structural studies of a luminescent coordination polymer of calcium(II) complex of benzilic acid

Single crystals of a new calcium(II) complex of benzilic acid, [Ca(C₁₄H₁₁O₃)₂(C₁₄H₁₂O₃)₂] have been successfully grown by gel diffusion technique at room temperature. Single crystal X-ray diffraction study reveals that the compound belongs to orthorhombic system with space group Fddd. The adjacent CaO₈ units are linked via O–H–O interaction to form one dimensional polymeric chains. The extensive hydrogen bonding interactions lead to a supramolecular structure. The grown crystals were further characterized by elemental analysis, FT-IR, UV–Visible, thermogravimetric, powder X-ray diffraction and solid state photoluminescence studies.     

Highly facile and stereoselective intramolecular [2 +2]photocycloadditions of bis(alkenoyl)ketenedithioacetals

The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,7-substituted-1,6-heptadiene-3,5-diones results in favorable spatial relationships between the alkenoyl groups to effect efficient intramolecular cycloadditions: irradiation of bis(alkenoyl)ketenedithioacetals in solution leads to facile and stereospecific intramolecular [2 + 2] photocycloadditions resulting in the formation of substituted bicyclo[3.2.0]heptane-2,4-diones, the observed conformational rigidity of which is attributed to the push-pull character of the ketenedithioacetal group.     

Synthesis, spectroscopic characterization, and antimicrobial activity of cobalt(II) complexes of acetone-N(4)-phenylsemicarbazone: crystal structure of [Co(HL)2(MeOH)2](NO3)2

Four Co(II) complexes, [Co(HL)₂](OAc)₂, [Co(HL)₂Cl₂], [Co(HL)₂(MeOH)₂](NO₃)₂, and [Co₂(HL)₄(SO₄)₂] (HL = acetone-N(4)-phenylsemicarbazone) were synthesized and characterized by physicochemical and spectroscopic methods. The magnetic susceptibility measurements indicate that the complexes are paramagnetic with three unpaired electrons. In all the complexes, the semicarbazone is coordinated as a neutral bidentate ligand. The structure of [Co(HL)₂(MeOH)₂](NO₃)₂ was confirmed by single crystal X-ray crystallography. The ligand is neutral and bidentate, being coordinated to the cobalt atom through the carbonyl oxygen and the azomethine nitrogen. Intermolecular hydrogen bonding and C–H···π interactions combine to stabilize the crystal structure. The ligand and its two complexes [Co(HL)₂Cl₂] and [Co(HL)₂(MeOH)₂](NO₃)₂ were screened for their antibacterial and antifungal activities using disk diffusion methods.     

Synthesis and Crystal Structure Analysis of 3,3'-[(3-Sulfanyl Phenyl)Methylene]Bis(4-Hydroxy-2H-1-Benzopyran-2-One) : 5-Methyl-1,3-Thiazol-2(3H)-Imine

Crystallography Reports - The structure of 3,3'-[(3-sulfanylphenyl)methylene]bis(4-hydroxy-2H-1-benzopyran-2-one) : 5-methyl-1,3-thiazol-2(3H)-imine was determined by X-ray crystallography. It...     

Synthesis and Crystal Structure of 1,7-Bis(4-methoxyphenyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione

Abstract  

The synthesis and crystal structure of 1,7-bis(4-methoxyphenyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione is described. This compound crystallizes in the space group P2₁ with unit cell parameters a = 14.207 ?, b = 7.752(1) ?, c = 19.473(1) ?, β = 91.00(3)°, with two molecules in the asymmetric unit. The ketenedithioacetal functionality present between the carbonyl groups prevents the possibility of keto-enol tautomerization in this compound. The cinnamoyl groups are organized parallel to each other due to the push–pull nature of the ketenedithioacetal functionality.     

Growth, spectral, and thermal characterization of 2-hydroxy-3-methoxybenzaldehyde semicarbazone

2-Hydroxy-3-methoxybenzaldehyde semicarbazone (HMBS) has been synthesized from 2-hydroxy-3-methoxybenzaldehyde and semicarbazide hydrochloride using sodium acetate as catalyst. Good quality single crystals of HMBS were successfully grown by slow evaporation method at room temperature using a mixture of DMF and ethanol as solvent. Fourier transform infrared and Fourier transform Raman spectral studies have been performed to identify the functional groups. Single-crystal XRD study was conducted to obtain the crystal structure and lattice parameters. The grown crystal was subjected to ¹H- and ¹³C-NMR spectral studies in order to confirm its structure and purity. The compound crystallizes into a monoclinic P21/c space group. Intermolecular hydrogen-bonding interactions facilitate unit cell packing in the crystal lattice. The UV–Vis spectrum confirmed the transparency of the compound between the wavelengths 420 and 1,100 nm, which is a characteristic property of a nonlinear optical (NLO) material. The thermal decomposition of the compound under static air atmosphere was investigated by simultaneous TG–DTG at a heating rate of 10 °C min^?1. The NLO property of HMBS was confirmed from the second-harmonic generation by Kurtz–Perry powder test.     

Synthesis and structural characterization of sol–gel derived titania/poly (vinyl pyrrolidone) nanocomposites

Non hydrolytic sol–gel method was employed to synthesize pure anatase TiO₂ nanocrystals using tetra isopropyl orthotitanate and poly vinylpyrrolidone as precursors. The structural analyses of the prepared samples were carried out using Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric and differential thermal analysis (TG–DTA), X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). The capping of PVP around TiO₂ nanoparticles was confirmed by FT-IR spectroscopy, the interaction being via bridging oxygens of the carbonyl (C=O) and the nanoparticle surface. The XRD, Raman and TEM results indicate that the prepared samples had a pure anatase nano-TiO₂ structure. The particle size analysed by TEM ranged between 7 and 12 nm. The size of the nanocrystals evaluated from the XRD spectra and TEM micrograph is well in agreement. The spacing for the crystal planes was also determined using the ImageJ program applied to the TEM micrographs.     

Crystal Structures of 1,7-Bis(furyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione and 1,7-bis(thienyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione

Abstract  

The title compounds (bis(alkenoyl) ketene dithioacetals) were prepared starting from the cyclic acyl ketene dithioacetal and aromatic aldehydes. These compounds were characterized by IR, ¹H NMR, mass spectral studies and X-ray crystal structure analysis. The bis(furyl) ketene dithioacetal crystallized in the space group P[`\text1] P{\bar{\text{1}}} with unit cell dimensions a = 7.7626(12) ?, b = 9.0217(13) ?, c = 26.827(5) ?, α = 86.271(14)°, β = 87.643(14)°, γ = 66.286(11)° and the structure was refined to an R-factor of 0.0528 while bis(thienyl) ketene dithioacetal crystallized in the space group P2₁/c with unit cell dimensions a = 10.2433(9) ?, b = 10.4142(6) ?, c = 18.0973(18) ?, β = 106.0° and the structure was refined to an R-factor of 0.0446. The ketenedithioacetal functionality present between the carbonyl groups prevents the possibility of keto-enol tautomerization in these compounds. In both the crystal structures, the crystal packing is stabilized by C–H···O hydrogen bonds as well as van der Waals interactions.     

Crystal Structure of 1,7-Bis(4-chlorophenyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione

Abstract  The synthesis and crystal structure of 1,7-bis(4-chlorophenyl)-4-(1,3-dithiolan-2-ylidene)-1,6-heptadiene-3,5-dione is described. This compound is a curcuminoid analogue, configurationally symmetric about the C4–C5 atoms and also retains the two fold axis in the crystal phase. This compound crystallizes in the space group C2/c with unit cell parameters a = 19.203(1) ?, b = 13.147(1) ?, c = 8.801(1) ?, β = 112.99(1)°, with half a molecule in the asymmetric unit. The ketenedithioacetal functionality present between the carbonyl groups prevents the possibility of keto-enol tautomerization in this compound. The push-pull nature of the ketenedithioacetal functionality organizes the cinnamoyl groups parallel to each other. Index Abstract  The details regarding synthesis and crystal structure of the title compound which is a curcuminoid analogue is reported in this paper.      

Crystal growth,characterization and photoluminescence study of a novel one dimensional coordination polymer of Cd(II) with thiophene-2,5-dicarboxylic acid

A novel one dimensional coordination polymer of Cd(II) with thiophene-2,5-dicarboxylic acid (H₂tdc), {[Cd(tdc) (H₂O)₃]·1.5H₂O}_n has been prepared by gel diffusion method. Elemental analysis, single crystal and powder X-ray diffraction studies, FT-IR and UV–visible spectral studies were used to characterize the title compound. Cd-thiophene units form a linear chain in the crystal structure. Thiophene rings of a linear chain are stacked parallel to each other while the thiophene rings of the adjacent chains are intercalated and stacked ant-parallel to each other. Extensive hydrogen bond formation and π-π interactions between thiophene moieties are responsible for the supramolecular architecture. TG/DTG studies confirm the presence of both lattice and coordinated water molecules. Photoluminescence studies showed that the title compound is red shifted by 46 nm compared to ligand.