Stilbazolium Derivatives Research Articles

A new stilbazolium family crystal of 1-methyl-2-[2-(3-nitro-phenyl)-vinyl]-pyridinium iodide (MNPI): Investigation of the growth, structural, optical, surface and third order nonlinear optical properties

A new stilbazolium derivative crystal of 1-methyl-2-[2-(3-nitro-phenyl)-vinyl]-pyridinium iodide (subsequently referred to as MNPI) has been grown using the slow evaporation method. Single-crystal XRD was employed to analyse the crystalline nature of the MNPI crystal, and it was found that MNPI crystallizes in the triclinic structure with the centrosymmetric space group P-1. The molecular weight of the elements present in the MNPI was affirmed by CHN elemental analysis. The Nuclear Magnetic Resonance (NMR) spectroscopic investigation confirmed the molecular structure of the MNPI crystal. FT-IR spectral analysis was used to identify the fundamental vibrational frequencies of specific functional groups present in the compound. The intermolecular interactions were studied using Hirsfeld surface analysis. Optical characterization has been carried out to find its optical transmittance efficiency and energy bandgap. According to the photoluminescence experiment, the MNPI crystal can be used as a green emission light source. Using the etching studies, the growth features of MNPI were studied. The surface properties of the crystal were studied using Atomic Force Microscopy (AFM). The title crystal was subjected to the single beam Z-scan technique to obtain its third-order nonlinear susceptibility. Its third-order nonlinear optical nature is compared with other reported centrosymmetric phase crystals.

A New Non-linear Stilbazolium Derivative Crystal of 4-[2-(3 Methoxy-phenyl)-vinyl]-1-methyl-pyridinium+ Iodide− (MMPI): Analysis of Its Structural, Surface, Optical and NLO Properties

New organic stilbazolium family of 4-[2-(3 methoxy-phenyl)-vinyl]-1-methyl-pyridinium+ iodide− (MMPI) was successfully synthesized using the condensation reaction method. The recrystallization process was carried out to improve the purity of the synthesized material, and MMPI and grown into a single crystal by the solvent evaporation method. The solubility of the (MMPI) material was taken at different temperatures with a mixture of solvent Methanol: Acetonitrile (1:1). The grown MMPI crystal structure and cell parameters were solved via single crystal X-ray diffraction analysis. The structural formation of the title material was also confirmed by Nuclear Magnetic Resonance spectroscopic (NMR) studies. The experimental vibrational bands in the synthesized material have been assigned by Fourier Transform Infrared (FT-IR) spectrum analysis. From the optical analysis, the grown crystal’s lower cut-off wavelength, transmittance range, and optical band gap were calculated. Chemical etching analysis was carried out on the grown crystal surface (MMPI) to study the surface property of the grown MMPI crystal. Along with etching, atomic force microscope (AFM) and scanning electron microscope (SEM) were also used to analyses the grown MMPI crystal surface. Hirshfeld surface analysis was used to analyses the intermolecular interactions. HOMO and LUMO energies were calculated theoretically using the Gaussian View 6 programmer. The chemical activity was evaluated via the molecular electrostatic potential using the density functional theory (DFT) method. The third-order nonlinear optical parameters of the title crystal were evaluated at He-Ne laser (632.8 nm) source with the single beam Z-scan technique. In addition, it shows significant reverse saturable absorption and self-defocusing.

A novel stilbazolium derivative crystals of 4-[2-(4-dimethyl amino-phenyl)-vinyl]-1-methyl-pyridinium+ bromide- (DMSB) single crystal: exploration of the growth, molecular structure, linear optical, and third order nonlinear properties.

A novel third-order stilbazolium derivative single crystal, 4-[2-(4-dimethyl amino-phenyl)-vinyl]-1-methyl-pyridinium bromide (DMSB), was fruitfully harvested using methanol as a medium, through a slow evaporation technique. The solubility of the prepared DMSB powder was experimentally tested at different temperatures (30 °C to 50 °C) with a methanol solvent. Single crystal X-ray diffraction analysis (SCXRD) implied that the DMSB crystal crystallized in a centrosymmetric fashion (space group P21/c) with the monoclinic crystal system. The molecular weight of the element present in DMSB was confirmed by CHN elemental analysis. Nuclear magnetic resonance (NMR) spectroscopic study confirmed the molecular structure of the DMSB crystal. All the functional group vibrations raised from the title compound were studied using Fourier transform infrared spectroscopy (FTIR). From the UV-visible spectrum, the absorbance nature and band gap of the grown DMSB crystal were determined. The photoluminescence study of the grown crystal exhibited an emission peak at 660 nm, which is attributed to the red light emission in the EM spectrum. The morphological characteristics of the crystal were characterized using atomic force microscopy (AFM). Hirshfeld surface analysis was employed to quantitatively explore the non-covalent interactions that are accountable for the crystal packing. The third-order nonlinear susceptibility was determined experimentally and it was found to be 1.6 × 10-8 esu. These favourable Z-scan analysis results indicate that the DMSB crystal is a good candidate for different applications, such as photonics devices, optical computing, optical switches, and optical limiting.

Selective enhancement of organic dye properties through encapsulation in rotaxane orientational isomers.

We report the synthesis and characterisation of [2]rotaxanes based on a stilbazolium dye and a calix[6]arene macrocycle. Since both components are non-symmetric, two orientational isomers are obtained. The two isomers display distinct photophysical and photochemical properties in solution and solid state, superior to the unencapsulated dye.

Theoretical Model of Polarization Effects on Third-Order NLO Properties of the Stilbazolium Derivative Crystal.

The linear and nonlinear properties of the stilbazolium derivative, 2-[2-(3-hydroxy-4-methoxy-phenyl)-vinyl]-1-methyl-pyridinium naphthalene-2-sulfonate dihydrate crystal (VSNS), were investigated using an iterative electrostatic embedding scheme and density functional theory (DFT). The dipole moment and second hyperpolarizability of the VSNS molecule are sharply influenced by its crystalline phase. Standard DFT global hybrids such as B3LYP and M06 are strongly benefited by the effects of crystalline polarization. The performance can be further improved by making small changes in the amount of Hartree-Fock exchange included in the hybrid, delivering good hyperpolarizability and spectroscopy.

Analysis of the growth and physicochemical properties of the newly developed stilbazolium derivative 4-N,N-dimethylamino-4-N-methyl stilbazolium 2-formyl benzene sulfonate (DSFS) single crystal: an effective material for nonlinear optical applications.

A novel ionic stilbazolium derivative single crystal of 4-N,N-dimethylamino-4-N-methyl stilbazolium 2-formyl benzene sulfonate (DSFS) was successfully cultivated with methanol as the solvent by using the slow evaporation technique. Structural confirmation was done using single-crystal X-ray diffraction (SCXRD), and the obtained results reveal that the DSFS crystal crystallized in a centrosymmetric pattern with P1̄ space group. The presence of different vibrational modes in the DSFS crystal is affirmed via Fourier transform infrared (FTIR) spectroscopy. Linear optical constants such as cut-off wavelength, bandgap, extinction coefficient, Urbach energy, electrical conductivity and optical conductivity of the titular crystal were found from ultraviolet-visible-near infra-red spectroscopy (UV-Vis-NIR). The emission wavelength of the title crystal lies in the red region (620 nm), which was confirmed from the photoluminescence spectroscopy (PL). The surface nature of the grown ionic crystal was examined through the etching and atomic force microscopy (AFM) technique. With a He-Ne laser as the source, Z scan analysis was carried out to study the third-order nonlinear properties of the DSFS crystal.

Investigation on the Effects of MnCl2 Doping on Structural and Optical Properties of DAST Single Crystals as Materials for Second Order Nonlinear Optics

AbstractThe intent is to explore the optoelectronic properties of metal ions doped stilbazolium derivative, 4‐N,N′‐dimethylamino‐N‐methyl‐4‐stilbazolium tosylate (MnCl2‐DAST) nonlinear optical crystal materials for the existing technological necessities. The Mn‐DAST single crystals are crystallized by adopting the slow evaporation solution technique (SEST). The structural and crystallographic dimensions of grown crystals are affirmed using single‐crystal X‐ray diffraction and powder crystal X‐ray diffraction. Fourier transform infrared spectra are performed to explicate the functional groups and energy dispersive X‐ray analysis (EDAX) spectra confirm the presence of the chemical elements of grown crystals. The UV–vis absorption spectra of DAST and Mn‐DAST crystals exhibit all possible n–π* and π–π* electronic transitions. The blue shift is observed in the doped materials due to the exchange of lone pair electrons between the metal ions and organic molecule. Tremendously, the second order harmonic generation (SHG) efficiency of Mn (0.01 mol%) doped DAST crystals has 1.68 times larger than that of DAST crystal. From the metal‐organic crystals (Mn‐DAST), all the results brought out are the promising materials in the design of nonlinear optical applications.

Investigation on nucleation, growth and physical properties of low soluble 4-N, N-dimethylamino-4-N’-methylstilbazolium 4-aminotoluene-3-sulfonate crystal – A potential NLO material

Terahertz generation requires materials with excellent nonlinear optical (NLO) properties and environment stability. 4-N, N-dimethylamino-4-N’-methylstilbazolium 4-aminotoluene-3-sulfonate (DAAS) an organic ionic compound is found to match these conditions but it is one of the sparingly soluble compounds among the stilbazolium derivatives causing difficulty in crystal growth. Therefore, in this article, the nucleation and growth kinetics of DAAS in different solvents are examined in order to understand and improve its crystal growth. The structural properties like symmetry, hydrogen bonding that contribute to crystal growth and morphology are studied and discussed. As nonlinear optical properties in organic compound is affected by vibration of the molecules, the existence of functional groups and various modes of vibration present in the molecule are identified and categorized by Fourier transform infrared (FT-IR) and FT-Raman analyses. Linear optical properties of the DAAS at molecular level, liquid and solid phases are investigated using density functional theory and UV-Visible spectroscopic technique. The NLO properties of DAAS molecule like the first order hyperpolarizability and mean polarizability is predicted using density function theory and the second harmonic generation efficiency is determined using Kurtz powder test. The thermal stability of DAAS is compared with other highly nonlinear optical stilbazolium derivatives.

Second Harmonic Generation Responses of Ion Pairs Forming Dimeric Aggregates.

A sequential approach combining molecular dynamics and density functional theory calculations has been worked out to unravel the second harmonic generation responses of anion-cation (AC) pairs when they form dimeric aggregates, where the cation is a stilbazolium derivative and the anions range from small inorganic iodide to medium-size organic p-toluenesulfonate. These complexes showed a strong self-aggregation behavior in molecular dynamics simulations within high-concentration conditions and formed stable dimeric aggregates, (AC)2, which can adopt different structural shapes from stacked, Λ, to head-to-head configurations. These various structures are associated with different symmetries, which are shown to modulate the second- and third-order nonlinear optical (NLO) responses. By consolidating the NLO results of this work with those previously obtained for single AC pairs [ J. Chem. Inf. Model. 2020, 60, 4817-4826], we have been able to explain the experimentally observed variations of the electrical-field-induced second harmonic generation (EFISHG) responses of these complexes as a function of concentration [ ChemPhysChem 2010, 11, 495-507]. Moreover, results have highlighted that (i) the second-order contribution, μβ//, dominates the global EFISHG response; (ii) the μβ// responses of dimers are about half of those computed for the parent AC pairs, while the third-order contributions, γ//, are reduced by only 10%; (iii) these distinct trends are ascribed to the formation of dimers adopting mainly Λ and head-to-head shapes, increasing the centrosymmetric character, in comparison to the monomers, a situation in which the second-order response cancels out as well as influences the dipole moment on μβ//; (iv) the presence of a strong amino donor group in the cation enhances the μβ// response by 1 order of magnitude and γ// by about a factor of 2; and finally, (v) dimeric aggregation has similar effects on the hyper-Rayleigh scattering response, βHRS, as on μβ//, while it reduces the one-dimensional character of βHRS. This work constitutes a step forward for the modeling of the NLO responses of AC aggregates in solution.

Potential aromatase inhibitors and antiestrogen agents based on stilbene and stilbazole derivatives

Abstract. Widely used forms of endocrine therapy for women with hormone-dependent breast cancer include blocking the biosynthesis of estrogens through using inhibitors of cytochrome P450 19A1 (aromatase). A series of new stilbene and stilbazole based aromatase inhibitors on are prepared. Z-isomers of 4-(2-(pyridin-4-yl)-1-(1H-1,2,4-triazol-1-yl)vinyl) benzonitrile, 4-(2-(pyridin-3-yl)-1-(1H-1,2,4-triazol-1-yl)vinyl)benzonitrile, 4-(2-(4-fluorophenyl)-1-(1H-1,2,4-triazol1-yl)vinyl)benzonitrile, 4-(2-(4-chlorophenyl)-1-(1H-1,2,4-triazol-1-yl)vinyl)benzonitrile, 4-(2-(4-bromophenyl)-1-(1H-1,2,4triazol-1-yl)vinyl)benzonitrile, 4-(2-(3,4-dimethoxyphenyl)-1-(1H-1,2,4-triazol-1-yl)vinyl)benzonitrile were prepared by condensation of 4-((1H-1,2,4-triazol-1-yl)methyl)benzonitrile and corresponding aldehyde in presence of strong base followed by dehydration of obtained alcohols. Isomerization to corresponded E-isomers was carried out in the presence of UV light.

Construction of Chiral Nanoassemblies Based on Host-Guest Complexes and Their Responsive CD and CPL Properties: Chirality Transfer From 2,6-helic[6]arenes to a Stilbazolium Derivative.

A couple of water-soluble chiral 2,6-helic[6]arene derivatives P-H1 and M-H1 were synthesized, and they could form 1:1 stable complexes with 4-[(4′-N, N-diphenylamino)-styryl]-N-methylpyridinium iodide (G) in water. Compared with G, the host-guest complexes exhibited enhanced fluorescence, which might be attributed to the spatial confinement of G and restriction of aggregation-caused quenching (ACQ) effects. Based on the host-guest complexation, the first helic[6]arene-based chiral assemblies were then constructed, and they showed rectangular or hexagonal nanostructures by scanning electron microscopy (SEM) images. Interestingly, the assemblies showed clear mirror-image circular dichroism (CD) and circularly polarized luminescence (CPL) spectra in aqueous solution, revealing a consecutive chirality transfer from the chiral macrocyclic cavities of the hosts to G. Moreover, the supramolecular chirality of the assemblies could also show responsiveness to the pH values and temperatures of the system.

Structural, spectral, thermal, and optical studies of stilbazolium derivative crystal: (E)-4-(3-hydroxy-4-methoxystyryl)-1-methyl pyridinium iodide monohydrate

In the current research, (E)-4-(3-hydroxy-4-methoxystyryl)-1-methyl pyridinium iodide monohydrate (HMSI) has been prepared through Knoevenagel condensation and crystallized by slow evaporation technique. Crystallographic analysis has been carried out to study the crystal structure and unit cell parameters. The fundamental vibration frequencies of specific chemical functional groups were detected by infrared absorption spectrum. Further the molecular structure of the grown crystal was confirmed by nuclear magnetic resonance spectroscopic analysis. Thermal stability (145 °C) and meting point (248 °C) of the HMSI material have been elaborated by means of thermogravimetric and differential scanning calorimetric (TG/DSC) analysis. The crystal was found to be transparent above 460 nm with the band gap of 2.63 eV obtained from transmission spectral analysis. The growth features of HMSI crystal were examined to check for the defects using an optical microscope. Crystal surface damage by Nd: YAG laser at 1.064 μm radiation was measured to be 1.98 GW/cm2. Further, the nonlinear response of HMSI has been studied using Z-scan technique and it was found that the title crystal is capable of exhibiting self-focusing nature with reverse saturable absorption. The evaluated nonlinear susceptibility is in the order of 10−6 esu which is slightly higher compared to other third-order stilbazolium derivative crystals.

Microscopic environment and molecular orientation of guest molecules within polyfluorinated surfactant and clay hybrids: Photochemical studies of stilbazolium derivatives

Three kinds of cationic aromatic alkenes, trans-stilbazolium derivatives: trans-4-[2-[4-phenyl]ethenyl]-1-pyridinium chloride (1a), trans-4-[2-[4-phenyl]ethenyl]-1-methylpyridinium bromide (1b), and trans-4-[2-[4-(4′-hexadecyloxy)phenyl]ethenyl]-1-methylpyridinium bromide (1c), were each cointercalated with a cationic polyfluorinated surfactant (C3F-S) within the interlayer of cation-exchangeable clay (SSA) to form hybrid compounds (C3F-S/SSA hybrids). The molecular orientations of the intercalated cationic molecules within the C3F-S/SSA hybrids were investigated photochemically using the stilbazolium derivatives as probes. Compound 1a exhibited selective excimer emission, indicating that at least two 1a molecules take on proximal orientations. However, the major photoproduct from 1a was the cis-isomer, and photodimer production was negligible. Absorption spectroscopic analysis showed that cointercalated 1a molecules were deprotonated within the C3F-S/SSA hybrid. These results suggested that deprotonated 1a was situated in a hydrophobic environment formed by the alkyl chains of C3F-S molecules. Compound 1b also exhibited selective excimer emission and both syn-head-to-head and syn-head-to-tail cyclodimers were obtained, suggesting that 1b could be competitively coadsorbed with C3F-S up to the amount of 100% vs CEC of SSA to form parallel conformational aggregates on the same side of the SSA surface. The amount of 1b that was directly adsorbed on the SSA surface was proportional to the sum of all cationic molecules present (1b and C3F-S). The remaining 1b molecules were solubilized as aggregates in the long alkyl chain “forest” of C3F-S in an antiparallel manner. Compound 1c exhibited predominantly monomer emission, and the cis-isomer was observed as the major photoproduct. These results indicated that cationic 1c was adsorbed as isolated monomers in the C3F-S/SSA hybrids because of the formation of hydrophobic interactions with the substituted long alkyl chains of 1c and C3F-S molecules. Thus, it was revealed that C3F-S/SSA provides a unique microenvironment for guest molecules, such as cationic stilbazolium derivatives, through a delicate balance among (1) electrostatic interactions exerted by the negatively charged SSA surface, (2) hydrophobic interactions from the long alkyl chain of C3F-S, and (3) both hydrophobic and lipophobic interactions from the perfluoropropyl chains of C3F-S that form a polyfluorinated “wall”.

1,2,4,5-Benzenetetracarboxylic acid: a versatile hydrogen bonding template for controlling the regioselective topochemical synthesis of head-to-tail photodimers from stilbazole derivatives.

The crystal engineering of hydrogen bonded organic assemblies based on 1,2,4,5-benzenetetracarboxylic acid (H4bta) and stilbazole derivatives (1-10) is exploited to provide regio-controlled [2 + 2] photocycloadditions in the solid state. Single crystal X-ray diffraction analyses have revealed that all the arrays are built-up from the self-assembly of the (H2bta)2- dianion with two stilbazolium cations via O-HO- and N+-HO- charge-assisted H-bonding synthons: (4-Hstilbazolium+)2(H2bta2-). The dianion displays an interesting diversity of H-bonding motifs. Such structural flexibility allowed us to obtain four structure-types defined by the preferential formation of intramolecular or intermolecular hydrogen bonds between carboxylate-carboxylic groups. In these ionic assemblies two predominant structural H-bonding patterns were observed. The first pattern is characterised by the formation of intramolecular H-bonds in the dianion, leading to discrete assemblies based on ternary arrays. The second hydrogen pattern consists of 2-D hydrogen networks built-up from the self-assembly of anions via intermolecular H-bonds that are linked to the cations. Two additional examples, in which the dianion is self-assembled in two types of ribbons, were also observed. Another supramolecular feature predominant in all these arrays is the stacking of the cations in a head-to-tail fashion, which is controlled via cation-π interactions. These arrays are photoactive in the solid state upon UV-irradiation leading to the regioselective synthesis of rctt-cyclobutane head-to-tail-isomers in high to quantitative yield. In this work, the template tolerance either to steric or electronic effects by changing the number or positions of the supramolecular interactions exerted by distinctive functional groups was also explored. In addition, assemblies bearing 2-chloro (7 and 8) and 3-chloro-4-stilbazole (1 and 9) crystallize in two different crystalline forms, leading to novel examples of supramolecular isomers with similar solid state reactivity.

Synthesis and nonlinear optical properties of pyridoxine-based stilbazole derivatives and their azo-analogs

ABSTRACTThe syntheses of a series of novel derivatives of stilbazole and their azo-analogs bearing the phenylalkenyl and phenyldiazenyl substituents at position 6 of the pyridoxine ring are reported. The observed cis/trans regioselectivity in the Wittig reaction between triphenylbenzylphosphonium chloride and carbonyl derivatives of pyridoxine ketal is discussed with respect to transition state intermediates, nature of base used in the reaction, and resonance transformations in the pyridoxine system. The azo-derivatives are obtained by azocoupling of the diazonium salts of sulfanilic or 4-aminophenyl-1,3-disulfonic acids with the corresponding pyridoxine acetals. Nine compounds from the obtained experimental series are capable of emitting second harmonic generation light, although with a reduced efficiency as compared to well known KH2PO4 or LiIO3 perovskite crystals, but with excellent beam resistance under laser irradiation, which makes them potential starting points for the development of novel nonlinear optical materials.

Synthesis, growth, crystal structure and characterization of new stilbazolium derivative single crystal: (E)-4-(3-ethoxy-2-hydroxystyryl)-1-methyl pyridinium iodide (3ETSI)

Organic single crystals of new stilbazolium derivative, (E)-4-(3-ethoxy-2-hydroxystyryl)-1-methyl pyridinium iodide (3ETSI), was grown by slow evaporation technique. Single crystal X-ray diffraction study revealed that 3ETSI crystallizes in monoclinic crystal system with centrosymmetric space group P21/c. The characteristic functional groups of the grown crystal were identified by FT-IR spectral studies. The 1H NMR spectral studies further confirm the molecular structure of the grown crystal. The thermal behaviour of 3ETSI crystal was studied by TG/DSC analysis. The grown crystal was found to be transparent in the region between 471 and 800 nm as indicated by the UV–visible spectral studies. Photoluminescence spectrum of 3ETSI crystal shows broad green emission peak at 529 nm. The mechanical strength of the grown crystal was estimated by Vickers microhardness tester. The laser damage threshold of 3ETSI crystal was found to be 2.5 GW/cm2 using Nd: YAG laser (1064 nm). Etching studies enunciate the two-dimensional (2D) layer growth mechanisms in the grown crystal. The third-order nonlinear optical properties including nonlinear refractive index (n2), nonlinear absorption coefficient (β), and third-order nonlinear optical susceptibility (χ(3)) of 3ETSI crystal were investigated by the Z-scan technique using continuous wave (CW) He-Ne laser at 632.8 nm.

Synthesis, growth, and characterization of new stilbazolium derivative single crystal: 2-[2-(2,4-dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide for third-order NLO applications

2-[2-(2,4-Dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DMPI), a new organic stilbazolium derivative was synthesized and grown by slow evaporation technique. The crystal structure of the grown crystal was solved by single crystal X-ray diffraction analysis and it was found that DMPI crystallizes in triclinic structure with the centrosymmetric space group Pī. Various functional groups of the grown crystal were identified using FT-IR spectral analysis. The molecular structure of DMPI was further confirmed by 1H NMR and 13C NMR spectral studies. The linear optical studies revealed that the grown crystal has a wide transparency range from 481 to 800 nm, which is suitable for opto-electronic and nonlinear optical applications. The luminescence spectrum of DMPI showed yellow emission radiation at 571 nm. TG/DTA analysis revealed that the grown crystal was thermally stable up to 232 °C. Microhardness studies confirmed the reverse indentation size effect of DMPI. The dielectric behaviour of DMPI was analyzed by dielectric studies with various frequencies at different temperatures. The surface damage threshold study showed that the grown crystal has higher optical radiation stability against 1064 nm Nd: YAG laser. Studies of its nonlinear optical properties using a Z-scan technique indicated that DMPI crystal possesses a saturable absorption and the self-focusing effect. Negative photo conducting nature of the grown crystal was obtained by photoconductivity measurements.

Synthesis, growth, structure and characterization of 1-Ethyl-2-(2-p-tolyl-vinyl)-pyridinium iodide (TASI) – An efficient material for third-order nonlinear optical applications

A new organic stilbazolium derivative, 1-Ethyl-2-(2-p-tolyl-vinyl)-pyridinium iodide (TASI), was grown from methanol:acetonitrile (1:3) mixed solvent by slow evaporation technique. Single crystal X-ray diffraction analysis revealed that TASI crystallizes in triclinic system with a centrosymmetric space group P-1. The molecular structure and the presence of expected functional groups of TASI were confirmed by 1H NMR and FT-IR spectroscopic studies. The HOMO and LUMO energies influence the charge transfer takes place within the molecule. The grown crystal was thermally stable up to 210 °C as determined by TG/DTA analysis. UV-Vis-NIR spectral study showed that the grown crystal was transparent in the wavelength range of 438–1100 nm. Mechanical behaviour and surface laser damage threshold were studied to find the suitability of the grown crystal for device fabrication. Studies of its third-order nonlinear optical properties using a Z-scan technique demonstrates that TASI crystal is capable of exhibiting reverse saturable absorption and self-focusing performance with the second-order molecular hyperpolarizability (γ) 4.983 × 10−34 esu. The third-order nonlinear susceptibility of TASI was found to be 8.931 × 10−6 esu, which is higher than a few other stilbazolium derivative crystals.

Investigation on growth, optical and thermal properties of stilbazolium derivative crystal: 4-N,N-dimethylamino-4′-N′-methylstilbazolium 2,4-dimethylbenzenesulfonate

AbstractMetathesis ionic exchange reaction process was used to synthesize a novel nonlinear optical material: 4-N,N-dimethylamino-4′- N′-methylstilbazolium 2,4-dimethylbenzenesulfonate (DSDMS). The growth of DSDMS single crystals was carried out by adopting the solution growth technique. The crystal perfection and lattice parameters were elucidated from single XRD and powder XRD, respectively and its morphology was interpreted by WinXMorph program. FT-IR and Raman spectral analyses confirmed the existence of functional groups and their corresponding vibrational modes. UV-Vis spectral studies revealed the optical transmission region. Mechanical stability of the crystal was determined from Vickers microhardness number Hv, Meyer’s index n and elastic stiffness constant C11. Dielectric and thermal behavior of the grown crystal were elucidated by using impedance analyser and thermogravimetric analysis.

Supramolecular discotic nematic liquid crystals built through simple hydrogen bonding between 1,3,5-tris(4-hydroxyphenyl)benzene and stilbazole derivatives

ABSTRACTNew supramolecular discotic nematic liquid crystals have been prepared simply through hydrogen bonding between the non-mesogenic core of 1,3,5-tris(4-hydroxyphenyl)benzene and the peripheral arms of stilbazole derivatives with different alkyl chain lengths. The discotic mesophases formed by simple hydrogen bonding were examined by POM, DSC, and XRD. The nematic columnar and discotic nematic mesophases were observed depending on the length of alkyl chains around the aromatic core by introducing the curved structure in three arms of supramolecular discotic mesogens. Our controlled methodology will be helpful for providing a convenient and effective way to prepare the rarely found discotic nematic liquid crystals.