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Novel tris-buffer based Schiff base bearing long flexible alkoxy arm and its lanthanide complexes: mesomorphism and photoluminescence
摘要： A new liquid crystalline salicylaldimine Schiff base having pendant hydroxymethyl (-CH2OH) groups and a series of lanthanide(III) complexes of the type, [Ln(LH)3(NO3)3] {Ln= La, Pr, Sm, Gd, Tb; LH=(E)-2-((1, 3-dihydroxy-2-(hydroxyl methyl) propan- 2-ylimino)methyl)-5-(hexadecyloxy) phenol} have been synthesised. The compounds were characterised by FT-IR, 1H NMR, 13C NMR, UV-Vis, and FAB-mass spectroscopy. Thermal behaviour of these compounds was studied using polarizing optical microscopy (POM) and differential scanning calorimetry. The phase confirmation and molecular organisation in the mesophase was ascertained by variable temperature powder X-ray diffraction (XRD) study. The ligand and the complexes both showed highly viscous smecticA and columnar mesophase, respectively. A bilayer self organization of the ligand molecules with interdigitation of the alkyl chains in the mesophase is proposed. Molecular organizations of the complexes in the mesophase involve arrangement of all the aliphatic chain pointing in same direction leading to lamellar columnar phase. The ligand showed an intense blue emission at 452 nm while the gadolinium(III) complex exhibited an intense emission at 458 nm (λex= 310 nm). The samarium(III) complex is a bright orange light emitter over a wide range upon UV irradiation.
关键词： mesophase,Schiff base,lanthanidomesogen,Luminescent,XRD
更新于2025-09-10 09:29:36
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Synthesis, Crystal Structure and Photophysical Properties of Two Reduced Schiff Bases Derived from 5-Aminoisophthalic Acid
摘要： Two reduced Schiff bases, namely 5-[(2-hydroxybenzyl)amino]isophthalic acid (1) and 5-[(pyridin-4-ylmethyl)amino] isophthalic acid (2), were synthesized in two-step method using 5-aminoisophthalic acid as the starting material, and were characterized by single-crystal X-ray diffraction, elemental analysis, infrared, 1H NMR, mass, absorption and fluorescence spectra. Both 1 and 2 crystallize in monoclinic system with space groups P21/c for 1 and P21/n for 2. Photophysical properties of both 1 and 2 are significantly different from those of raw material 5-aminoisophthalic acid due to stronger p → π conjugation when one amino hydrogen atom in 5-aminoisophthalic acid is substituted with electron-donor group. 1 displays a very strong narrow-band blue fluorescence with the maximum peak at 439 nm, a high quantum efficiency up to 64%, and a narrow full width at half maximum of 35 nm, while 2 has a broader and weaker fluorescence with the peak at 418 nm and FHWM of about 50 nm.
关键词： 5-[(2-Hydroxybenzyl)amino]isophthalic acid,5-Aminoisophthalic acid,Photophysical property,5-[(Pyridin-4-ylmethyl)amino]isophthalic acid,Crystal structure,Reduced Schiff base
更新于2025-09-04 15:30:14
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Molecular structures, DFT studies and their photophysical properties in solution and solid state. Microwave-assisted multicomponent synthesis of organotin bearing Schiff bases
摘要： A couple of luminescent organotin compounds derivated from ligands-ONO were obtained by multicomponent microwave assisted synthesis in short time (15 min) and good yields: ((E)-8, 8-8-diphenylbenzo[d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (1) and (E)11, 13- di-tert-butyl, 8- diphenylbenzo [d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (2)). Both compounds were fully characterized by NMR (1H, 13C, and 119Sn; 2D-NMR, HETCOR and COSY), UVeVis, IR, and high-resolution mass spectrometry. The X-ray structures of two complexes demonstrate that the tin atoms adopt a bipyramidal trigonal geometry. The 119Sn NMR chemical shifts of the tin atom in the complexes are also consistent with the presence of pentacoordinate tin centers. The photophysical properties in solution and solid state, DFT, and voltammetry the two complexes have been determined.
关键词： Fluorescence,X-ray,Schiff base,Organotin,Microwave assisted synthesis
更新于2025-09-04 15:30:14
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Electronic properties of B12N12 fullerene–like nanoclusters functionalized with Schiff bases: a DFT study
摘要： In the present study, electronic properties of B12N12 nanocage functionalized with Schiff bases are studied by means of density functional theory (DFT) calculations at wB97XD/6-31+G(d,p) computational level. Adsorption of Schiff bases on the surface of B12N12 nanocage leads to one local minimum with the adsorption energy in the range of ? 63.61 and ? 157.37 kJ/mol. Effect of substitution of Schiff bases with electron-donating and electron-withdrawing groups on the adsorption energy, electronic properties, and thermodynamic parameters of studied complexes has been reported. In general, adsorption of H2C=N–C6H4–R Schiff bases on B12N12 nanocage is stronger than adsorption of R2C=N–C6H5 moieties. The result of present study may be used for surface modification of B12N12 nanocage based on interaction with Schiff bases.
关键词： DFT,B12N12 nanocage,TDOS,Schiff base,Functionalization
更新于2025-09-04 15:30:14
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Synthesis and characterization of alkoxy substituted p-cyano stilbene schiff bases
摘要： Schiff bases consist of aromatic have been used in various application including biological, inorganic and analytical chemistry. It also has been applied in optical and electrochemical sensors to enable detection of enhance selectivity and sensitivity of the sensors. These compounds might give excellent prospect in sensor. Schiff bases derived from 4-(4- aminostyryl)benzonitrile and three 4-alkoxybenzaldehyde derivatives are synthesis using ethanol as solvent. All compounds were characterized by Fourier transform-infrared spectroscopy (FT-IR), UV-Vis spectrophotometer and Nuclear Magnetic Resonance (NMR). FTIR showed formation of C=N (imine) stretching vibrations at range of 1604 cm-1 to 1609 cm- 1. In UV-vis, π-π* electronic transition of the C=N can be observed at peak range 361 nm. While in the δH NMR the peak of CH=N (Imine) group was found at δ 8.32-8.34 ppm and 13C NMR for three Schiff bases were discovered at δ 158.72, 158.73 and 158.71 ppm. In previous study there are several types of linker that have been used in E-DNA, especially alkanethiol. In this study, three new Schiff base derivatives have been synthesized and characterized due to it promising in sensor which prompted us to apply its as future potential linker in electrochemical DNA sensor.
关键词： future potential linker in E-DNA,Characterization,Synthesis,Schiff base
更新于2025-09-04 15:30:14
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Constructing excellent electromagnetic wave absorber with dielectric-dielectric media based on 3D reduced graphene and Ag(I)-Schiff base coordination compounds
摘要： The dielectric-dielectric composite (SRGA) for electromagnetic absorber was fabricated via integrating Ag(I)-Schiff base coordination compounds (SSBCC) with three-dimensional reduced graphene aerogel (3D-rGA) powders. SRGA showed excellent electromagnetic wave absorption properties in terms of re?ection loss, absorption band width and absorber thickness. Specially, when the mass ratio of SSBC to 3D-rGA powders was 1:3 (SRGA-25), the maximum value of re?ection loss at 2 mm was up to (cid:1)63.82 dB and the effective frequency bandwidth of 6.28 GHz (10.16e16.44 GHz) at 2.5 mm can be obtained. The mechanism investigation of electromagnetic wave absorption for SRGA showed that the enhanced electromagnetic wave absorption was ascribed to enhanced polarization loss derived from good 3D-conductive-network units of 3D-rGA, abundant interfaces caused by the media heterostructure due to the introduction of SSBCC and the good impedance matching condition. And 3D-rGA based materials might be put into practical application only in powder state due to the very low strength of the buck state. Therefore, the investigation on SRGA in our contribution is considered to be an actual performance evaluation of the materials based on three-dimensional graphene for microwave attenuation. This work also provided a method for fabricating excellent graphene-based electromagnetic wave absorbers by simply mixing a suitable dielectric lossy material, e.g. SSBCC.
关键词： Electromagnetic wave absorber,Schiff base,Composite,Microwave attenuation,Graphene aerogel
更新于2025-09-04 15:30:14
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Fast response two-photon fluorogenic probe based on Schiff base derivatives for monitoring nitric oxide levels in living cells and zebrafish
摘要： Numerous excellent fluorogenic probes for NO detection based on NO-mediated reactions have been developed. However, some of them still suffer from limitations such as low selectivity, slow response, and a short excitation wavelength (o500 nm). Herein, a novel two-photon fluorogenic probe (XNO1) based on a Schiff base derivative has been reported for the first time. This new mechanism with a Schiff base structure as the specific response moiety towards NO endows the probe with fast responsibility, high selectivity and pH-independent properties. Furthermore, XNO1 has been demonstrated to be lysosome-targeted and to successfully monitor exogenous/endogenous NO in living cells and zebrafishes with one- and two-photon fluorescence imaging.
关键词： living cells,nitric oxide,two-photon fluorogenic probe,zebrafish,Schiff base derivatives
更新于2025-09-04 15:30:14