scholarly journals Synthesis and Structural Characterization of Some Lanthanide(III) Nitrate Complexes with a Mesogenic Schiff-Base, N,N’-di-4-(4’-heptadecyloxybenzoate) salicylidene-1,3-diaminopropane Derived from 2,4- dihydroxybenzaldehyde

2020 ◽  
Vol 41 (1) ◽  
pp. 16-25
Author(s):  
Prem Kumar Shrestha ◽  
Pawan Raj Shakya
Keyword(s):  
Schiff Base ◽  
Liquid Crystalline ◽  
Molar Conductance ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Spectral Techniques ◽  
Crystalline Property ◽  
Elemental Analyses ◽  
Overlap Parameter

Complexes of La(III), Pr(III), Nd(III), Sm(III), Gd(III) and Dy(III) with the Schiff-base, N,N′-di-4-(4’-heptadecyloxybenzoate)salicylidene-1,3-diaminopropane, (abbreviated as H2L) have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic, electronic, infrared, 1H and 13C NMR spectral techniques. The nephelauxetic ratio (β), the bonding parameter (b1/2), Sinha’s parameter (%δ) and angular overlap parameter (η) have been calculated from the electronic spectra of Pr(III), Nd(III), Sm(III) and Dy(III) complexes. Infrared and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as LH2) to the Ln(III) ions through two phenolate oxygens, rendering the overall geometry around Ln(III) to distorted square antiprism. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) shows the liquid crystalline property of the ligand with a nematic (N) mesophase. Among the metal complexes, only that of the Gd(III) exhibits smectic B (SmB) and nematic (N) phases. 

scholarly journals Novel banana-discotic hybrid architectures

2009 ◽  
Vol 5 ◽  
Author(s):  
Hari Krishna Bisoyi ◽  
H T Srinivasa ◽  
Sandeep Kumar
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Microscopy ◽  
Elemental Analysis ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
Spectral Techniques ◽  
Design And Synthesis ◽  
Chemical Structures ◽  
Crystalline Property ◽  
Liquid Crystalline Property

Here we present the design and synthesis of novel banana-discotic dimers and banana-bridged discotic dimers. The chemical structures have been characterized by spectral techniques and elemental analysis. The thermal behaviors of the compounds have been investigated by polarizing optical microscopy and differential scanning calorimetry. None of these synthesized compounds exhibit any liquid crystalline property probably because of the incompatibility of the bent-core with the discotic core.

scholarly journals Co(III) and VO(IV) complexes with a new bidentate Schiff base: Interaction with BSA and antimicrobial studies

2019 ◽  
Vol 9 (1) ◽  
pp. 3776-3782 ◽  
Keyword(s):  
Schiff Base ◽  
Analytical Techniques ◽  
Molar Conductance ◽  
Base Interaction ◽  
1H And 13C Nmr ◽  
Pyramidal Geometry ◽  
Antimicrobial Studies ◽  
Biological Studies ◽  
Bacteria And Fungi

A Schiff base ligand L was prepared from the condensation of 2-amino-3-benzyloxypyridine and 5-chlorosalicylaldehyde. The ligand forms complexes with Co(III) and VO(IV) in good yield. Design, synthesized and characterization of cobalt(III) and oxidovanadium(IV) with (E)-2-((3-(benzyloxypyridinylimino) methyl)-4-chlorophenol (L) are described. The prepared complexes were characterized by different analytical techniques elemental analysis, molar conductance, infrared spectra, 1H and 13C NMR, mass, electronic absorption and TGA. The coordination geometry is octahedral in C1 and C2, while complexes C3 and C4 show a square-pyramidal geometry. Numerous biological studies have been conducted on L and Co(III) and VO(IV) complexes. The results of antimicrobial studies indicated that all compounds had antimicrobial activity against bacteria and fungi. The binding of metal complexes with BSA (bovine serum albumin) was reported. The results of these indicated that Co(III) and VO(IV) are significantly quenching fluorescence intensity of BSA, that results in changing its conformation and results in a static quenching.

Synthesis and characterization of novel liquid and liquid crystalline phthalocyanines

2004 ◽  
Vol 08 (10) ◽  
pp. 1175-1186 ◽  
Author(s):  
Mahmut Durmuş ◽  
Colette Lebrun ◽  
Vefa Ahsen
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Metal Salt ◽  
Electronic Spectroscopy ◽  
Scanning Calorimetry ◽  
Elemental Analyses ◽  
Columnar Mesophases ◽  
New Compounds ◽  
Hexagonal Columnar

Peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy) substituted metal free-, Ni (II) and Zn (II) phthalocyanines have been synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt ( NiCl 2 and Zn ( OOCCH 3)2) or a strong organic base. The new compounds have been characterised by elemental analyses, IR, NMR, mass spectra and electronic spectroscopy. The mesogenic properties of these new materials were studied by differential scanning calorimetry (DSC), optical polarised microscopy and X-ray investigations. The effects of peripheral or non-peripheral substitution of (13,17-dioxanonacosane-15-hydroxy) to the phthalocyanine ring are also investigated. It is found out that non-peripheral substituted phthalocyanine derivatives (4a-c) are liquid at room temperature whereas, peripheral substituted phthalocyanine derivatives (7a-c) exhibit ordered discotic hexagonal columnar mesophases ( Col h) at room temperature.

Novel Hydroxy- and Methyl-Terminated Triaromatic Schiff Base Compounds: Synthesis and Mesogenic Properties

2010 ◽  
Vol 63 (2) ◽  
pp. 276 ◽  
Author(s):  
Natarajan Senthilkumar ◽  
Tanneru Narasimhaswamy ◽  
Aravamudhan Raghavan
Keyword(s):  
Differential Scanning Calorimetry ◽  
Schiff Base ◽  
Model Compounds ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Methyl Group ◽  
Smectic Phases ◽  
Phase Range ◽  
Fourier Transform Ir

A series of Schiff base hydroxy-mesogens and their model compounds have been synthesized. The mesogen is constructed from three-ring-containing mesogens linked through ester and azomethine groups with a terminal hydroxy group. The related model compounds were also synthesized with varying chain length with a terminal methyl group and their properties were compared with that of hydroxy mesogens. Extensive characterization of all mesogenic compounds was carried out by Fourier-transform IR, 1H and 13C NMR and mass spectroscopy. The phase characteristics such as nature of phase, melting and clearing temperatures and phase range were evaluated using a hot-stage optical polarizing microscope and differential scanning calorimetry. The appearance of enantiotropic smectic phases is due to the high molecular polarizability of the triaromatic core with azomethine and ester linkages.

scholarly journals Synthesis and Structural Characterization of (E)-4-[(2-Hydroxy-3-methoxybenzylidene)amino]butanoic Acid and Its Novel Cu(II) Complex

Molbank ◽  
10.3390/m1179 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1179
Author(s):  
Eleftherios Halevas ◽  
Antonios Hatzidimitriou ◽  
Barbara Mavroidi ◽  
Marina Sagnou ◽  
Maria Pelecanou ◽  
...  
Keyword(s):  
Schiff Base ◽  
Gamma Aminobutyric Acid ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Polymeric Compound ◽  
Bridging Ligands ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
Ft Ir

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.

Thermal, Mechanical and Magneto-Mechanical Characterization of Liquid Crystalline Elastomers Loaded with Iron Oxide Nanoparticles

2015 ◽  
Vol 1718 ◽  
pp. 3-7
Author(s):  
Stephany Herrera-Posada ◽  
Barbara O. Calcagno ◽  
Aldo Acevedo
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Liquid Crystalline ◽  
Molar Mass ◽  
Oxide Nanoparticles ◽  
Magnetic Actuation ◽  
Scanning Calorimetry ◽  
Elastomeric Matrix ◽  
Alternating Magnetic Fields

ABSTRACTLiquid crystalline elastomers (LCEs) are materials that reveal unusual mechanical, optical and thermal properties due to their molecular orientability characteristic of low molar mass liquid crystals while maintaining the mechanical elasticity distinctive of rubbers. As such, they are considered smart shape-changing responsive systems. In this work, we report on the preparation of magnetic sensitized nematic LCEs using iron oxide nanoparticles with loadings of up to 0.7 wt%. The resultant thermal and mechanical properties were characterized by differential scanning calorimetry, expansion/contraction experiments and extensional tests. The magnetic actuation ability was also evaluated for the neat elastomer and the composite with 0.5 wt% magnetic content, finding reversible contractions of up to 23% with the application of alternating magnetic fields (AMFs) of up to 48 kA/m at 300 kHz. Thus, we were able to demonstrate that the inclusion of magnetic nanoparticles yields LCEs with adjustable properties that can be tailored by changing the amount of particles embedded in the elastomeric matrix, which can be suitable for applications in actuation, sensing, or as smart substrates.

scholarly journals Synthesis, Mesomorphism and the Optical Properties of Alkyl-deuterated Nematogenic 4-[(2,6-difluorophenyl)ethynyl]biphenyls

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4653
Author(s):  
Jakub Herman ◽  
Piotr Harmata ◽  
Michał Czerwiński ◽  
Olga Strzeżysz ◽  
Marta Pytlarczyk ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Optical Properties ◽  
Liquid Crystalline ◽  
Near Infrared ◽  
Synthesis And Characterization ◽  
Molecular Approach ◽  
Scanning Calorimetry

The synthesis and characterization of new deuterated liquid crystal (LC) compounds based on phenyl tolane core is described in this paper. The work presents an alternative molecular approach to the conventional LC design. Correlations between molecular structure and mesomorphic and optical properties for compounds which are alkyl-hydrogen terminated and alkyl-deuterium, have been drawn. The compounds are characterized by mass spectrometry (electron ionization) analysis and infrared spectroscopy. They show enantiotropic nematic behavior in a broad temperature range, confirmed by a polarizing thermomicroscopy and differential scanning calorimetry. Detailed synthetic procedures are attached. Synthesized compounds show a significantly reduced absorption in the near-infrared (NIR) and medium-wavelength infrared (MWIR) radiation range, and stand as promising components of medium to highly birefringent liquid crystalline mixtures.

scholarly journals Synthesis , Spectroscopic and Antibacterial Studies of Zinc(II) Complexes Derived from Salicylaldehyde, Leucylalanine and Glycylglycine

2012 ◽  
Vol 9 (3) ◽  
pp. 532-540 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Schiff Base ◽  
Bacterial Species ◽  
Conductivity Measurement ◽  
Growth Inhibitor ◽  
Molar Conductance ◽  
Diffusion Method ◽  
Schiff Base Ligands ◽  
Elemental Analyses ◽  
L1 And L2

Two Schiff base ligands L1 and L2 have been obtained by condensation of salicylaldehyde respectively with leucylalanine and glycylglycine then their complexes with Zn(II)were prepared and characterized by elemental analyses , conductivity measurement , IR and UV-Vis .The molar conductance measurement indicated that the Zn(II) complexes are 1:1 non-electrolytes. The IR data demonstrated that the tetradentate binding of the ligands L1 and L2 . The in vitro biological screening effect of the investigated compounds have been tested against the bacterial species Staphlococcus aureus, Escherichia coil , Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa by the disc diffusion method . A comparative study of inhibition values of the Schiff base ligands and their complexes indicated that the complexes exhibit higher antimicrobial activity than the free ligands . Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium .

Synthesis and Characterization of Cr (III) Macrocyclic Schiff Base Complexes

2021 ◽  
pp. 269-274
Author(s):  
Dharmendra Kumar Sahu ◽  
Shekhar Srivastava
Keyword(s):  
Schiff Base ◽  
Molar Conductance ◽  
Photoelectron Spectra ◽  
Schiff Base Complexes ◽  
Squaric Acid ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Trimesic Acid ◽  
Macrocyclic Schiff Base

Ninety Cr(III) macrocyclic Schiff base complexes of the type [CrL_n^(1-10) X_2 ]X(Where X = Cl- or NO-3 or CH3COO- and = macrocyclic Schiff base ligands derived from condensation of trimesic acid or p-phthalic acid or squaric acid with different aliphatic diamines) have been synthesised and characterised by elemental analysis; molar conductance; electronic spectra; IR; magnetic moment and XPS i.e. X-ray Photoelectron spectra data. An octahedral geometry was established for them.

scholarly journals Synthesis, Spectroscopic, Molecular Structure, and Antibacterial Studies of Dibutyltin(IV) Schiff Base Complexes Derived from Phenylalanine, Isoleucine, and Glycine

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Har Lal Singh ◽  
Jangbhadur Singh
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Schiff Bases ◽  
Molar Conductance ◽  
Schiff Base Complexes ◽  
Spectral Studies ◽  
E Coli ◽  
Elemental Analyses ◽  
In Vitro Antibacterial Activity

New series of organotin(IV) complexes and Schiff bases derived from amino acids have been designed and synthesized from condensation of1H-indole-2,3-dione, 5-chloro-1H-indole-2,3-dione, andα-amino acids (phenylalanine, isoleucine, and glycine). All compounds are characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (1H,13C, and119Sn NMR) spectral studies. The results suggest that Schiff bases behave as monobasic bidentate ligands and coordinate with dibutyltin(IV) in octahedral geometry according to the general formula [Bu2Sn(L)2]. Elemental analyses and NMR spectral data of the ligands with their dibutyltin(IV) complexes agree with their proposed distorted octahedral structures. Few representative compounds are tested for their in vitro antibacterial activity against Gram-positive (B. cereus,Staphylococcusspp.) and Gram-negative (E. coli,Klebsiellaspp.) bacteria. The results show that the dibutyltin complexes are more reactive with respect to their corresponding Schiff base ligands.

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