Mesogenic complementary absorbing dyads based on porphyrin and perylene units

2018 ◽  
Vol 22 (01n03) ◽  
pp. 221-232
Author(s):  
Xiangfei Kong ◽  
Hongkang Gong ◽  
Shengping Dai ◽  
Wei Yao ◽  
Linping Mu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Emission Spectra ◽  
Molecular Orbitals ◽  
Resonance Spectroscopy ◽  
Response Curves ◽  
Scanning Calorimetry ◽  
Broad Absorption ◽  
Active Materials ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals

Five novel dyads, consisting of a tetraphenylporphyrine unit connected to a perylene monoimide diester unit via a flexible bridge -CONH-(CH[Formula: see text]- (n [Formula: see text] 4, 6, 8, 10 and 12), have been synthesized. Their structures were characterized by [Formula: see text]C and [Formula: see text]H nuclear magnetic resonance spectroscopy, infrared spectroscopy, mass spectrometry and elemental analysis. The UV-vis absorption spectra revealed these dyads have broad optical absorption in the ultraviolet and visible regions due to the complementary absorption of the two units. The differential scanning calorimetry traces and polarized optical microscopy textures showed all these dyads have columnar liquid crystal phases. Cyclic voltammetry revealed the highest occupied molecular orbitals of the dyads located on the porphyrin units, and the lowest unoccupied molecular orbitals located on the perylene units. In addition, these results were in agreement with that of the theoretical modeling. When excited at 423 or 473 nm, the photoluminescent emission spectra showed that the degree of fluorescence quenching of porphyrin units increased as the spacers became shorter. This quenching was ascribed to intramolecular photoinduced electron transfer, which also induced the dyad molecules to form the charge-separated states. The charge-separated molecules were further confirmed by the photocurrent response curves. These behaviors of broad absorption of the ultraviolet-visible light, yielding the charge-separated states of the molecules when excited and the formation of columnar liquid crystal phase made these dyads candidates for single-component photovoltaic active materials.

scholarly journals Molecular Structure Modulated Trap Distribution and Carrier Migration in Fluorinated Epoxy Resin

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3071 ◽  
Author(s):  
Jin Li ◽  
Yufan Wang ◽  
Zhaoyu Ran ◽  
Hang Yao ◽  
Boxue Du ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Surface Charge ◽  
Epoxy Resin ◽  
Mobility Model ◽  
Molecular Orbitals ◽  
Chemical Calculation ◽  
Dissipation Process ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals ◽  
Positively Charged

Surface charge accumulation on epoxy insulators is one of the most serious problems threatening the operation safety of the direct current gas-insulated transmission line (GIL), and can be efficiently inhibited by the surface modification technology. This paper investigated the mechanisms of fluorination modulated surface charge behaviors of epoxy resin through quantum chemical calculation (QCC) analysis of the molecular structure. The results show that after fluorination, the surface charge dissipation process of the epoxy sample is accelerated by the introduced shallow trap sites, which is further clarified by the carrier mobility model. The electron distribution probability of the highest occupied molecular orbitals (HOMO) under positive charging and the lowest unoccupied molecular orbitals (LUMO) under negative charging shows distinctive patterns. It is illustrated that electrons are likely to aggregate locally around benzenes for the positively charged molecular structure, while electrons tend to distribute all along the epoxy chain under negatively charging. The calculated results verify that fluorination can modulate surface charge behaviors of epoxy resin through redesigning its molecular structure, trap distribution and charging patterns.

Observational studies of imperfect carbon cage structures of C 60 by high-resolution scanning tunnelling microscopy

1994 ◽  
Vol 444 (1921) ◽  
pp. 325-332 ◽  
Keyword(s):  
High Resolution ◽  
Molecular Orbitals ◽  
Scanning Tunnelling Microscopy ◽  
Carbon Cage ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Dynamics Simulations ◽  
First Time ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals

Anomalies in the morphology of the carbon cage of C 60 clusters have been investigated with atomic level resolution using high-resolution scanning tunnelling microscopy. The imperfect carbon cages have been resolved in the finest detail, which, for the first time, provide a remarkable confirmation of a variety of theoretical defect structures recently predicted by molecular dynamics simulations. The observed tunnelling spectra are consistent with the theoretical contention that the gap between the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) for the clusters is decreased with the presence of defects.

Blue Light Emission from a Rod-Like Liquid Crystal

2010 ◽  
Vol 428-429 ◽  
pp. 288-291 ◽  
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Light Emission ◽  
Tight Binding ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Blue Light Emission ◽  
Liquid Crystalline Phases ◽  
Dominant Peak ◽  
Blue Photoluminescence

A rod-like liquid crystal 4-butoxybenzylidene-4'-octylphenylamine was synthesized. The molecular structure and the liquid crystalline phases of the synthesized compound were characterized with the nuclear magnetic resonance spectroscopy, the differential scanning calorimetry, and the polarizing optical microscopy, respectively. The absorption measurement shows that the dilute tetrahydrofuran solutions of the rod-like liquid crystal absorb photons at about 290 and 330 nm, respectively; while the luminescence measurements indicate that this rod-like liquid crystal can give off intense blue photoluminescence with its dominant peak located at about 430 nm. Using Hückel tight-binding program, we have calculated the electronic structures of the liquid crystal, and the origin of the blue photoluminescence is discussed. Introduction

Synthesis and Characterization of a New Organometallic Palladium Coordinated Liquid Crystal

2010 ◽  
Vol 428-429 ◽  
pp. 117-121 ◽  
Author(s):  
Jian Qiang Liu ◽  
Xing Cheng Zhang ◽  
You Yong Dai ◽  
Hong Di Xiao ◽  
Shi Shen Yan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Optical Microscope ◽  
Resonance Spectroscopy ◽  
Functional Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Liquid Crystallinity ◽  
New Type ◽  
Clearing Temperature

A new organometallic palladium coordinated liquid crystal that is written by PdS4 has been synthesized by chelating reaction of the tetrachloropalladate (PdCl42-) and the star-like liquid crystal (S4) containing four butoxyazobenzene mesogens in its periphery. The structure and liquid crystallinity (LC) of PdS4 were characterized by infrared absorption spectroscopy (IR), ultraviolet absorption spectra (UV), nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing optical microscope (POM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The phase behavior of PdS4 is Cr167N232I200N170Cr, its melting point and clearing temperature are higher than those of the free azo ligand S4, its mesophase range is broader than S4’s. It will be used as a new type photoelectric functional material in the future.

Synthesis and Liquid Crystal Properties of a New Organometallic Palladium Complex

2011 ◽  
Vol 306-307 ◽  
pp. 242-245
Author(s):  
Jian Qiang Liu ◽  
Xing Qi Fu ◽  
Jian Ye Song ◽  
Yun Xu Fu ◽  
Xing Cheng Zhang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Optical Microscope ◽  
Resonance Spectroscopy ◽  
Functional Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Liquid Crystallinity ◽  
Crystal Properties ◽  
New Type ◽  
Clearing Temperature

A new organometallic palladium coordinated liquid crystal that was written by PdS6 had been synthesized by chelating reaction of the tetrachloropalladate (PdCl42-) and the star-like liquid crystal (S6) containing four hexyloxyazobenzene mesogens in its periphery. The structure and liquid crystallinity (LC) of PdS6 were characterized by infrared absorption spectroscopy (IR), ultraviolet absorption spectra (UV), nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing optical microscope (POM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The phase behavior of PdS6 was Cr155N230I205N160Cr, its melting point and clearing temperature were higher than those of the free azo ligand S6, its mesophase range wass broader than S6’s. It will be used as a new type photoelectric functional material in the future.

scholarly journals Theoretical Study on Molecular Structure and Electronic Properties of New 1,3-Diaza-adamantan-6-ones Derivatives

2020 ◽  
Vol 20 (3) ◽  
pp. 638
Author(s):  
Haithem Abdulhasan ◽  
Ahmed Al-Yasari ◽  
Rahman Alasadi
Keyword(s):  
Electronic Properties ◽  
Theoretical Study ◽  
Dft Method ◽  
Molecular Orbitals ◽  
Molecular Structures ◽  
Computational Method ◽  
Basis Set ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals ◽  
Vibrational Wavenumbers

In this study, the structural geometry and vibrational frequencies (IR) of 1,3-Diaza-adamantane-6-ones derivatives including Adamantane (A), 1,3-Diaza-adamantan (D), 1,3-Diaza-adamantan-6-one (DO), 5-Benzyl-1,3-diaza-adamantan-6-one (BD), 5-(4-Hydroxybenzyl)-1,3-diaza-adamantan-6-one (HBD), 5-(4-Methoxybenzyl)-1,3-diaza-adamantan-6-one (MBD), and 5-(4-Hydroxy-3-methoxybenzyl)-1,3-diaza-adamantan-6-one (HMBD) were theoretically studied. In addition, molecular orbital energies, including the highest occupied molecular orbitals (HOMOs), and lowest unoccupied molecular orbitals (LUMOs), and electronic properties of the titled molecules were theoretically studied using the computational method. Optimized molecular structures were obtained by DFT method with the hybrid B3LYP functional at a relatively small basis set of 6-31G. The calculated vibrational wavenumbers were obtained using the same level of the theory mentioned above. The contributions to the molecular orbitals of adamantane and substituted-phenyl groups in the title compounds were determined. Moving from A to HMBD, a decrease in the value of LUMO and total energy are noticed, while an increase in the value of HOMO is noted. These findings are supported by the decreasing in the EHOMO-LUMO gap values. Furthermore, a decrease in the value of ionization potential (IP) is obtained, while an increase in the electronegativity (EA) is observed.

scholarly journals Polymer Dispersed Cholesteric Liquid Crystals With a Toroidal Director Configuration under an Electric Field

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 732
Author(s):  
Anna P. Gardymova ◽  
Mikhail N. Krakhalev ◽  
Victor Ya. Zyryanov ◽  
Alexandra A. Gruzdenko ◽  
Andrey A. Alekseev ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Electric Field ◽  
Point Defects ◽  
Structural Response ◽  
Optical Filters ◽  
Response Curves ◽  
Polymer Dispersed Liquid Crystal ◽  
Dichroic Dye ◽  
Polymer Dispersed

The electro-optical properties of polymer dispersed liquid crystal (PDLC) films are highly dependent on the features of the contained liquid crystal (LC) droplets. Cholesteric LC droplets with homeotropic boundaries can form several topologically different orientational structures, including ones with single and more point defects, layer-like, and axisymmetric twisted toroidal structures. These structures are very sensitive to an applied electric field. In this work, we have demonstrated experimentally and by computer simulations that twisted toroidal droplets reveal strong structural response to the electric field. In turn, this leads to vivid changes in the optical texture in crossed polarizers. The response of droplets of different sizes were found to be equivalent in terms of dimensionless parameters. In addition, the explanation of this phenomenon showed a comparison of theoretical and experimental structural response curves aids to determine the shape of the droplet. Finally, we demonstrated that the addition of a dichroic dye allows such films to be used as optical filters with adjustable color even without polarizers.

scholarly journals Physicochemical properties and structural dynamics of organic–inorganic hybrid [NH3(CH2)3NH3]ZnX4 (X = Cl and Br) crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ae Ran Lim ◽  
Sun Ha Kim ◽  
Yong Lak Joo
Keyword(s):  
Structural Dynamics ◽  
Chemical Shifts ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Scanning Calorimetry ◽  
Inorganic Hybrid ◽  
Halogen Atoms

AbstractThe physical properties of the organic–inorganic hybrid crystals having the formula [NH3(CH2)3NH3]ZnX4 (X = Cl, Br) were investigated. The phase transition temperatures (TC; 268K for Cl and 272K for Br) of the two crystals bearing different halogen atoms in their skeletons were determined through differential scanning calorimetry. The thermodynamic properties of the two crystals were investigated through thermogravimetric analysis. The structural dynamics, particularly the role of the [NH3(CH2)3NH3] cation, were probed through 1H and 13C magic-angle spinning nuclear magnetic resonance spectroscopy as a function of temperature. The 1H and 13C NMR chemical shifts did not show any changes near TC. In addition, the 1H spin–lattice relaxation time (T1ρ) varied with temperature, whereas the 13C T1ρ values remained nearly constant at different temperatures. The T1ρ values of the atoms in [NH3(CH2)3NH3]ZnCl4 were higher than those in [NH3(CH2)3NH3]ZnBr4. The observed differences in the structural dynamics obtained from the chemical shifts and T1ρ values of the two compounds can be attributed to the differences in the bond lengths and halogen atoms. These findings can provide important insights or potential applications of these crystals.

scholarly journals Synthesis and Characterization of N-Substituted Polyether-Block-Amide Copolymers

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 773
Author(s):  
Jyun-Yan Ye ◽  
Kuo-Fu Peng ◽  
Yu-Ning Zhang ◽  
Szu-Yuan Huang ◽  
Mong Liang
Keyword(s):  
Titanium Isopropoxide ◽  
Decomposition Temperature ◽  
Phenyl Isocyanate ◽  
Cross Linking ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Melt Polycondensation ◽  
Structural Regularity

A series of N-substituted polyether-block-amide (PEBA-X%) copolymers were prepared by melt polycondensation of nylon-6 prepolymer and polytetramethylene ether glycol at an elevated temperature using titanium isopropoxide as a catalyst. The structure, thermal properties, and crystallinity of PEBA-X% were investigated using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, and thermogravimetric analysis. In general, the crystallinity, melting point, and thermal degradation temperature of PEBA-X% decreased as the incorporation of N-methyl functionalized groups increased, owing to the disruption caused to the structural regularity of the copolymer. However, in N-acetyl functionalized analogues, the crystallinity first dropped and then increased because of a new γ form arrangement that developed in the microstructure. After the cross-linking reaction of the N-methyl-substituted derivative, which has electron-donating characteristics, with poly(4,4′-methylenebis(phenyl isocyanate), the decomposition temperature of the resulting polymer significantly increased, whereas no such improvements could be observed in the case of the electro-withdrawing N-acetyl-substituted derivative, because of the incompleteness of its cross-linking reaction.

scholarly journals Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Polyethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Soft Segment ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

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