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SYNTHESIS AND CHARACTERIZATION OF UNSYMMETRICAL BOROLE COMPLEXES OF HETEROCYCLIC ALDIMINES
PANDEY,TARUNA; SINGH,R.V.;
Boletín de la Sociedad Chilena de Química , 2000, DOI: 10.4067/S0366-16442000000100003
Abstract: recent developments in the chemistry of aldimines of boron are described.unsymmetrical borole complexes of aldimines derived from heterocyclic aldimineshave been characterized on the basis of ir, 1h-nmr, 13c-nmrand 11b-nmr spectral studies and elemental analysis and molecularweight determinations. spectral studies confirmed that the aldimines actin a monobasic bidentate fashion, rendering the non-metal tetracoordinated.the new complexes of the types [(b(c3h6o2)(ln)] and [b(c4h8o2)(ln)] were obtained by 1:1 molar reactions of unsymmetrical monoisopropoxyborane with heterocyclic aldimines in dry benzene. the liberated isopropanolwas fractionated off azeotropically with benzene and estimated.
SYNTHESIS AND CHARACTERIZATION OF UNSYMMETRICAL BOROLE COMPLEXES OF HETEROCYCLIC ALDIMINES  [cached]
TARUNA PANDEY,R.V. SINGH
Boletín de la Sociedad Chilena de Química , 2000,
Abstract: Recent developments in the chemistry of aldimines of boron are described.Unsymmetrical borole complexes of aldimines derived from heterocyclic aldimineshave been characterized on the basis of IR, 1H-NMR, 13C-NMRand 11B-NMR spectral studies and elemental analysis and molecularweight determinations. Spectral studies confirmed that the aldimines actin a monobasic bidentate fashion, rendering the non-metal tetracoordinated.The new complexes of the types [(B(C3H6O2)(Ln)] and [B(C4H8O2)(Ln)] were obtained by 1:1 molar reactions of unsymmetrical monoisopropoxyborane with heterocyclic aldimines in dry benzene. The liberated isopropanolwas fractionated off azeotropically with benzene and estimated. Se describen recientes desarrollos de la química de aldiminasde boro. Los complejos de boro y aldiminas asimétricas se han caracterizadopor estudios espectroscópicos de IR, 1H-NMR, 13C-NMRy 11B-NMR y también análisis elemental y determinacionesde peso molecular. Los estudios espectrales confirman que las aldiminasactúan como monobásicas bidentadas dando cuenta de la tetracoordinacióndel no-metal. Los nuevos complejos del tipo [(B(C3H6O2)(Ln)] y[B(C4H8O2)(L n)]fueron obtenidos por reacción molar 1/1 del monoisopropóxidode borano con la aldimina heterocíclica en benceno seco. El isopropanolliberado fue fraccionado desde el azeótropo con benceno y medido
Synthesis and thermal behavior of new liquid crystals arylaldoxime esters
Tavares, Aline;Arruda, Bárbara C.;Boes, Elvis S.;Stefani, Valter;Stassen, Hubert K.;Campo, Leandra F.;Bechtold, Ivan H.;Merlo, Aloir A.;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012000500013
Abstract: we report the synthesis of a series of liquid-crystalline materials based on arylaldoxime esters and the characterization of these materials by 1h, 13c nmr, atr/ft-ir spectroscopy and elemental analysis. the chemical stability and liquid-crystalline as well as photophysical properties of the compounds are described being dependent on the heating/cooling cycles. the changes in chemical stability and the liquid crystals properties of arylaldoxime esters were observed during these thermal cycles by ir analysis. all samples underwent a thermal degradation yielding the corresponding nitriles and carboxylic acid as evidenced by ir and 1h nmr spectra. due to the decomposition process, information about the mesomorphic behaviour is lost. the uv-vis absorption spectra in solution display three absorption bands between 230 and 340 nm. the fluorescence spectra exhibit a broad and structureless emission band located at 430 nm. ab initio calculations were performed to obtain information on the molecular structure and properties of the title compounds.
Synthesis of carbonated hydroxyapatite nanorods in liquid crystals
Campos, Daniella Dias Palombino de;Bertran, Celso Aparecido;
Materials Research , 2009, DOI: 10.1590/S1516-14392009000300003
Abstract: syntheses of calcium phosphate nanoparticles, carried out in systems formed from surfactant, oil and water, have resulted in materials with promising possibilities for application. the calcium phosphate particles were synthesized using two different liquid crystals, formed from renextm, cyclohexane and a salts solution. the morphology of the nanoparticles synthesized in the liquid crystals is similar to that of hydroxyapatite particles that form bone mineral, where collagen fibers connect these particles so as to form a composite. therefore, the synthesis of calcium phosphate nanoparticles in the systems used in this work can advance current understanding of mineralization processes that result in the formation of bone mineral.
Synthesis and Characterization of Bent-rod Liquid Crystals  [PDF]
Pablo Del Rosso,Sandra A. Hernandez,Raúl O. Garay
Molecules , 2000, DOI: 10.3390/50300383
Abstract: Two series of diesters with bend-rod shapes were synthesized and their thermal properties characterized by POM and DSC. The central group conformational mobility and polarity as well as the length of the mesogenic groups were varied in order to correlate these parameters with mesophase stability. Results indicate that series II diesters are enantiotropic and that their mesophase sensitivity to central group structural changes is limited.
Investigation of the Role of Electrogenerated N-Heterocyclic Carbene in the Staudinger Synthesis in Ionic Liquid  [PDF]
Marta Feroci
International Journal of Organic Chemistry (IJOC) , 2011, DOI: 10.4236/ijoc.2011.14028
Abstract: Electrogenerated N-heterocyclic carbene (NHC), obtained by cathodic reduction of Bmim-BF4, behaves as organocatalyst and base in the Staudinger synthesis from an acyl chloride and a deactivated imine in ionic liquid to yield ?-lactams. The effect of many parameters (temperature, amount of electricity, substituents, presence of an external base) has been evaluated and a tentative mechanism for the Staudinger synthesis in a very polar medium like the ionic liquid reported. The yields of isolated ?-lactams are good, starting from non-electrophilic imines, and predominantly trans lactams are obtained with a good diastereomeric ratio.
Synthesis and Characterization of Some N-Heterocyclic Carbohydrate Derivatives  [PDF]
M. A. Martins Alho,N. B. D’Accorso
Molecules , 2000, DOI: 10.3390/50300381
Abstract: The nucleophilic bimolecular substitution on 1,2:3,4-di-O-isopropylidene-α-Dgalactopyranose with NH2-heterocyclic derivatives allows us to obtain some new compounds with potential biological activities. The characterization of them as well as a discussion of their reactivities toward sulfur analogues are present.
Multi-Scale Characterization of Lyotropic Liquid Crystals Using 2H and Diffusion MRI with Spatial Resolution in Three Dimensions  [PDF]
Diana Bernin, Vanessa Koch, Magnus Nydén, Daniel Topgaard
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0098752
Abstract: The ability of lyotropic liquid crystals to form intricate structures on a range of length scales can be utilized for the synthesis of structurally complex inorganic materials, as well as in devices for controlled drug delivery. Here we employ magnetic resonance imaging (MRI) for non-invasive characterization of nano-, micro-, and millimeter scale structures in liquid crystals. The structure is mirrored in the translational and rotational motion of the water, which we assess by measuring spatially resolved self-diffusion tensors and spectra. Our approach differs from previous works in that the MRI parameters are mapped with spatial resolution in all three dimensions, thus allowing for detailed studies of liquid crystals with complex millimeter-scale morphologies that are stable on the measurement time-scale of 10 hours. The data conveys information on the nanometer-scale structure of the liquid crystalline phase, while the combination of diffusion and data permits an estimate of the orientational distribution of micrometer-scale anisotropic domains. We study lamellar phases consisting of the nonionic surfactant C10E3 in O, and follow their structural equilibration after a temperature jump and the cessation of shear. Our experimental approach may be useful for detailed characterization of liquid crystalline materials with structures on multiple length scales, as well as for studying the mechanisms of phase transitions.
Synthesis, spectral characterization and antibacterial studies of palladium(II) complexes of heterocyclic thiones  [PDF]
Syed Ahmed Tirmizi,Shafqat Nadeem,Abdul Hameed,Muhammad Hamid Sarwar Wattoo,Aneela Anwar,Zameer Ahmed Ansari,Saeed Ahmad
Spectroscopy: An International Journal , 2009, DOI: 10.3233/spe-2009-0387
Abstract: Reactions of K2[PdCl4] with heterocyclic thiones in molar ratios of 1:2 and 1:4 in water-methanol medium yielded the palladium(II) complexes with the general formula of either [Pd(L)Cl2], [Pd(L)2]Cl2 or [Pd(L)4]Cl2 where L ═ Imidazolidine-2-thione (Imt), 2-Mercaptopyridine (Mpy), 2-Mercaptopyrimidine (Mpm), 6-Mercaptopurine (6-Mp) and Thionicotinamide (Tna). The complexes were characterized by elemental analysis and spectroscopic (IR, 1H and 13C NMR) methods. An upfield shift in the >C═S resonance of thiones in 13C NMR and downfield shift in N–H or aromatic proton resonances in 1H NMR are consistent with the sulfur coordination to palladium(II). The complexes were screened for antibacterial activity, and the results showed that the complexes exhibited moderate activities as compared to that of a standard drug.
Synthesis and Characterization of Liquid Crystal Elastomer  [PDF]
Rita A. Gharde, Santosh A. Mani, Suman Lal, Samriti Khosla, S. K. Tripathi
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.66056
Abstract: The thermal and mechanical properties of Liquid Crystal Elastomers (LCEs) were characterized using various techniques for understanding of their physical behavior. The material used for investigation was synthesized by us, using Finklemann procedure, with proper cross linking density in nematic phase. The material is found to have unique coupling between anisotropicorder of liquid crystal component and elasticity of polymer network. The chemical structures were confirmed by Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM). Fabry Perot Scattering Studies (FPSS), Thermo gravimetric Analysis (TGA) and Differential Scanning Calorimatory (DSC) were used to study thermal properties. The mechanical properties were studied using force sensor. Our investigation shows that this synthesized Liquid Crystal Elastomer has ability of spontaneous change as a function of temperature and mechanical force, which shows it as a unique class of soft material.
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