scholarly journals An unsymmetrical porphyrin and its metal complexes: Synthesis, spectroscopy, thermal analysis and liquid crystal properties

2009 ◽  
Vol 74 (10) ◽  
pp. 1097-1104 ◽  
Author(s):  
Changfu Zhuang ◽  
Xuexin Tang ◽  
Dong Wang ◽  
Aiqing Xia ◽  
Wenhui Lian ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Liquid Crystalline ◽  
Thermal Studies ◽  
Luminescent Properties ◽  
Quantum Yields ◽  
Scanning Calorimetry ◽  
Crystal Properties

The synthesis and characterization of a new unsymmetrical porphyrin liquid crystal, 5-(4-stearoyloxyphenyl)phenyl-10,15,20-triphenylporphyrin (SPTPPH2) and its transition metal complexes (SPTPPM, M(II) = Zn, Fe, Co, Ni, Cu or Mn) are reported. Their structure and properties were studied by elemental analysis, and UV-Vis, IR, mass and 1H-HMR spectroscopy. Their luminescent properties were studied by excitation and emission spectroscopy. The quantum yields of the S1 ? S0 fluorescence were measured at room temperature. According to thermal studies, the complexes have a higher thermal stability (no decomposition until 200?C). Differential scanning calorimetry (DSC) data and an optical textural photograph, obtained using a polarizing microscope (POM), indicate that the porphyrin ligand had liquid crystalline character and that it exhibited more than one mesophase and a low-lying phase transition temperature, with transition temperatures of 19.3 and 79.4?C; the temperature range of the liquid crystal (LC) phase of the ligand was 70.1?C.

scholarly journals Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene)hydrazines

2019 ◽  
Vol 43 (1-2) ◽  
pp. 67-77 ◽  
Author(s):  
Adil A Awad ◽  
Al-Ameen Bariz OmarAli ◽  
Ahmed Jasim M Al-Karawi ◽  
Zyad Hussein J Al-Qaisi ◽  
Samer Ghanim Majeed
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Luminescent Properties ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
X Ray ◽  
Step Procedure ◽  
Liquid Crystalline Materials

{1-[4-( n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines ( n-alkoxy = O(CH2) nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.

Synthesis and Characterization of Stilbene Derivatives for Possible Incorporation as Smart Additives in Polymers Used as Packaging Films.

1997 ◽  
Vol 50 (4) ◽  
pp. 425 ◽  
Author(s):  
Gary M. Day ◽  
Owen T. Howell ◽  
Michael R. Metzler ◽  
Paul D. Woodgate
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystalline ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Packaging Films ◽  
Multiple Phase ◽  
Liquid Crystalline Phases ◽  
Crystal Properties ◽  
Stilbene Derivatives

Several series of stilbene derivatives for possible use as smart additives in polymers used as packaging films have been prepared and characterized. Differential scanning calorimetry was performed on some of the stilbenes in order to determine any liquid crystal properties. Those compounds which had multiple phase transitions were also shown to have two liquid crystalline phases according to optical microscopy.

scholarly journals Synthesis and Characterization of a New Bidentate Ligand 5-Substituted-(2-methyl-5-nitro-1-imidazomethyl)-1,3,4-oxadiazole-2-thione and its Metal Complexes of Ag(I), Cu(II) and Zn(II)

2011 ◽  
Vol 8 (s1) ◽  
pp. S127-S136
Author(s):  
Shabbir A. A. Kazi
Keyword(s):  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Thermal Studies ◽  
Bidentate Ligand ◽  
Octahedral Geometry ◽  
Spectral Studies ◽  
Ligand Molecule ◽  
H Nmr ◽  
Elemental Analyses

A new ligand (2-methyl-5-nitro-1-imidazomethyl)-1,3,4-oxadiazole-2-thione (L) and its Ag(I),Cu(II) and Zn(II) complexes were synthesized. The authenticity of the ligand and its transition metal complexes were established by elemental analyses, conductance and magnetic susceptibility measurements, as well as spectroscopic (IR,1H NMR, electronic, mass and ESR) and thermal studies. The IR spectral studies revealed the existence thiol-thione tautamerism in the ligand molecule. The magnetic and electronic spectral studies suggest an octahedral geometry for Cu(II) and Zn(II) complexes. The ligand acts as a bidentate coordinating through the N-3 nitrogen and the exocyclic sulfur atoms of oxadiazole rings. Antimicrobial screening of the ligand and its metal complexes were determined against the bacteriaEscherichia coliandSalmonella paratyphiA.

scholarly journals Template Synthesis and Characterization of Transition Metal Complexes of 13, 15 and 17-Membered Tetraamide Macrocyclic Disubstituted Dimethyl Tetrasubstituted Tetraazacycloalka Tetrasubstituted Tetraene Disubstiuted Diol

2020 ◽  
Vol 32 (3) ◽  
pp. 488-494 ◽  
Author(s):  
B. Vimala ◽  
S.R. Jayapradha ◽  
A. Selvan
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Thermal Studies ◽  
Synthesis And Characterization ◽  
Template Method ◽  
Magnetic Susceptibilities ◽  
X Ray ◽  
L 13

A series of new transition metal complexes [ML(Ln)Cl2] where Ln = L13, L15 and L17 (L(13) = 11,13-dimethyl-1,4,7,10-tetraazacyclotrideca-4,6,10,13-tetraene-5,6-diol, L(15) = 9,11-dimethyl-1,4,8,12-tetraazacyclopentadeca-1,3,8,11-tetraene-2,3-diol and L(17) = 10,12-dimethyl-1,4,9,13-tetraazacycloheptadeca-1,3,9,12-tetraene-2,3-diol) and M = Cu(II), Co(II), Ni(II), Mn(II) and Zn(II) have been synthesized by template method. All the synthesized complexes were characterized by IR, UV, ESR, X-ray microanalysis, elemental analysis, thermal studies and magnetic susceptibilities and the geometry of the complexes found to be octahedral.

scholarly journals Synthesis and Determination of Thermotropic Liquid Crystalline Behavior of Cinnamaldehyde-Based Molecules with Two Schiff Base Linking Units

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3780
Author(s):  
Zuhair Jamain ◽  
Nor Faizawani Omar ◽  
Melati Khairuddean
Keyword(s):  
Schiff Base ◽  
Liquid Crystal ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Condensation Reaction ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Crystal Properties ◽  
Structure Property Relationship

A series of liquid crystal molecules with two Schiff base linking units and a cinnamaldehyde core with different terminal groups were synthesized and characterized. The intermediates of 4-heptyloxybenzaldehyde (1a) and 4-dodeyloxybenzaldehyde (1b) were synthesized through the alkylation of 4-hydroxybenzaldehyde with a series of bromoalkane. A condensation reaction of cinnamaldehyde, 1,4-phenylenediamine and a series of substituted benzaldehydes with different terminal groups such as bromo, chloro, hydroxy, cinnamaldehyde, hydrogen, methoxy, heptyloxy and dodecyloxy produced a series of new cinnamaldehyde-based compounds, 2–9, respectively. All these compounds were characterized using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and CHN elemental analysis. The liquid crystal properties of these compounds were determined using polarized optical microscopy (POM), and their transitions were further confirmed using differential scanning calorimetry (DSC). Compounds with chloro, bromo, methoxy, heptyloxy, and dodecyloxy substituents are mesogenic compounds with nematic phase behavior. However, the other compounds were found to be non-mesogenic without any mesophase transitions. The structure–property relationship was investigated in order to study the effect of different terminal groups and Schiff base linking units on the liquid crystalline behavior of these compounds.

Synthesis and Properties of Novel Thiophene-Based Liquid Crystalline Conducting Polymers

2017 ◽  
Vol 25 (9) ◽  
pp. 669-676 ◽  
Author(s):  
Danesh Roudini
Keyword(s):  
Magnetic Field ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Electronic Properties ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystal Properties

Side-chain liquid crystalline polythiophenes were synthesised and the effects of the mesogenic units on the structure and electronic properties of the polymers were studied. The liquid crystal properties of the polymer films were studied using polarised hot-stage optical microscopy and differential scanning calorimetry, and X-ray diffractometry was used to investigate the effect of a magnetic field on the monomers and polymers.

scholarly journals New azobenzene liquid crystal with dihydropyrazole heterocycle and photoisomerization studies

2020 ◽  
Vol 7 (7) ◽  
pp. 200474
Author(s):  
Xiaoxuan Wang ◽  
Zhaoxia Li ◽  
Haiying Zhao ◽  
Shufeng Chen
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Ester Group ◽  
Azo Compounds ◽  
Scanning Calorimetry ◽  
Polarizing Microscopy ◽  
Mesogenic Unit ◽  
Crystal Properties ◽  
Azobenzene Derivatives ◽  
Long Chain

New azobenzene derivatives with dihydropyrazole heterocycle have been prepared and characterized. According to thermal polarizing microscopy and differential scanning calorimetry studies, the compounds consisting of four linearly linked rings and a long alkoxy chain on the azobenzene side ( 3a-8 and 3a-14 ) displayed no liquid crystal properties. When the length of mesogenic unit increased to five rings, except for compound 5a-8 , all compounds from 5a-10 to 5a-16 containing a long chain of 10–16 carbon atoms on the side of ester group displayed liquid crystalline properties, and the mesogenic domain gradually narrowed with increase of the chain length. However, in the case of the molecule with long alkoxy chains on both sides, only 5c-16 with a long chain of 16 carbon atoms exhibited liquid crystal behaviour. In addition, these azo compounds underwent isomerization from E to Z under ultraviolet irradiation and then thermal back relaxation slowly in the dark, which can be recycled many times.

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