117909-27-0

Upstream product

• 90-02-8 salicylaldehyde 
• 873-74-5 4-Aminobenzonitrile 

Downstream Products

• 622400-17-3 4-(2-hydroxybenzylamino)benzonitrile 
• 144989-74-2 4-(4H-Benzo[e][1,3]oxazin-3-yl)-benzonitrile 
• 873-74-5 4-Aminobenzonitrile 
• 1164105-20-7 bis(salicylidene-p-cyanoaniline)zinc(II) 

Relevant academic research and scientific papers

Solid state photochromism and thermochromism of two related N-salicylidene anilines

The crystalline structure and optical properties of N-salicylidene-p-cyanoaniline and N-salicylidene-p-carboxyaniline were investigated in solid state (microcrystalline powder), with the purpose to connect the effects of substitution and crystal packing with their optical properties. Diffuse reflectance and fluorescence spectroscopy were used to study the absorption and emission properties upon photoirradiation and cooling down to the liquid nitrogen temperature. The Stokes-shifted fluorescence, with a quantum yield of about 10-2-10-1, is given by the tautomeric cis-keto species formed as a result of the excited state intramolecular proton transfer from the initial enol structure. Despite their similar geometrical parameters, only SA-COOH is photochromic, which is in contradiction with literature. On the other side, the thermochromism is especially strong at SA-CN. The study shows the behavior of SA-CN similar to that of a classical anil, while SA-COOH presents interesting features that contradict the presumed behavior based only on its supramolecular structure.

Ligand dissociation/recoordination in fluorescent ionic zinc-salicylideneimine compounds: Synthesis, characterization, photophysical properties, and 1H NMR studies

A series of ionic zinc-salicylideneimine compounds, [HNEt 3][Zn(L)Cl2] (L = salH-4-CN, 1; sal Cl-4-CN, 2; salBr-4-CN, 3; salOMe-4-CN, 4) and [NEt4][Zn(salH-4-CN)Cl2] (5), have been synthesized and structurally characterized. Compounds 1-5 all display an intense fluorescence band in both solution (methanol, MeOH; acetonitrile, ACN; dimethylsulfoxide, DMSO; dichloromethane, DCM) and solid phases, with a maximum in the region of 515-560 nm and 529-573 nm, respectively. Detailed 1H NMR and optical spectroscopic studies indicate the occurrence of ligand dissociation and recoordination in 1-4 in solution, leading to an equilibrium between the zinc-salicylideneimine complex species, [Zn(L)Cl2] -, and the salicylideneimine free ligand, HL. The tendency of ligand dissociation is related to the solvent, the concentration, and the substitution of the salicylidene ring. The greatest degree of ligand dissociation is observed for 1-4 when dissolved in noncoordinating, less polar DCM solvent, followed by coordinating, high polar DMSO solvent. The least degree of ligand dissociation occurs in solutions of coordinating, moderately polar MeOH and ACN solvents for 1-3 and 4, respectively. Dilute solutions are likely characterized by the high degree of ligand dissociation, whereas the equilibrium shifts in favor of the complex [Zn(L)Cl2]- form at higher concentration. Furthermore, the electron-donating methoxy substitution in the salicylidene ring promotes a high tendency for ligand dissociation, while electron-withdrawing chloro and bromo groups cause the reverse tendency. The 1H NMR spectrum of 5 shows only one set of proton resonances in the aromatic region corresponding to the complex [Zn(salH-4-CN)Cl2] - species, indicating that the lack of ammonium proton would protect the complex form from ligand dissociation.

Influence of substituents on the structure of Schiff bases Cu(II) complexes

The relationship between molecular conformation and substituent effects of salicylaldehyde Schiff-base Cu(II) complexes was explored. For this study, eight samples of the complexes Cu(Sal-X)2 (X = OMe, Me, H, F, Cl, Br, CF3 and CN) w

Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi-aryl Schiff bases containing hydroxyl

Effect of substituents on the ultraviolet (UV) spectra of supermolecular system involving silver nanoparticles (AgNPs) and Schiff bases was investigated. AgNPs and 49 samples of model compounds (MC), bi-aryl Schiff bases containing hydroxyl (XBAY, involving 4-OHArCH?NArY, 2-OHArCH?NArY, XArCH?NAr-4′-OH, and XArCH?NAr-2′-OH), were synthesized. The size of AgNPs was characterized by transmission electron microscopy (TEM), and the UV absorption spectra of AgNPs, XBAYs, and MC-AgNPs mixed solutions were measured, respectively. The results show that (1) the size of AgNPs is larger in MC-AgNPs solutions than that in AgNPs solution due to the distribution of MC molecules on the surface of AgNPs; (2) the UV absorption wavelength of XBAYs changes in the action of AgNPs and their wavelength shift exists limitation between XBAY and MC-AgNPs solutions; and (3) the wavelength shift limit of MC-AgNPs (λWSL) is influenced by the substituents X and Y and the position of hydroxyl OH. The wavenumber ΔνWSL of λWSL can be quantified by employing the excited-state substituent constant σexCC and Hammett constant σ of substituents X and Y. Comparing with the 4-OH, the 4′-OH makes the ΔνWSL a red shift, whereas the 2′-OH, comparing with the 2-OH, makes the ΔνWSL a blue shift.

Remarkable difference between five- and six- number-membered ring transition states for intramolecular proton transfer in excited state

In this study, a range of organic dyes were prepared to investigate difference between five- and six- number-membered ring transition states for internal proton transfer in excited state. Different strength intramolecular hydrogen bond in the target dyes

Abnormal effect of hydroxyl on the longest wavelength maximum in ultraviolet absorption spectra for bis-aryl Schiff bases

Two sets of bis-aryl Schiff bases that contain 4(or 4′)-OH and 2(or 2′)-OH were synthesized. The first set consists of 4-HOArCH=NArY and XArCH=NArOH-4′, and the second set consists of 2-HOArCH=NArY and XArCH=NArOH-2′. Their ultraviolet absorption spectra were measured and investigated. A very interesting phenomenon was observed by analyzing their wave number νmax (cm?1) of longest wavelength maximum λmax (nm) of ultraviolet. Compared with the change regularity of the νmax of XArCH=NArY (where the X and Y excluded OH), the 4′-position hydroxyl (4′-OH) and 2′-position hydroxyl (2′-OH) have abnormal performance. The details are the following: the 4′-OH contributes an additional red shift to the νmax of XArCH=NArOH-4′ (λmax increase), whereas the 2′-OH contributes an additional blue shift to the νmax of XArCH=NArOH-2′ (λmax decrease). In addition, there are ortho steric effects of all 2-OH and 2′-OH on the νmax for 2-HOArCH=NArY and XArCH=NArOH-2′, and the ortho steric effect contributes a red shift to their νmax. These experimental facts can provide an important theoretical reference for us using aryl Schiff base compounds as optical materials and performing the molecular design.

Excited-state charge coupled proton transfer reaction via the dipolar functionality of salicylideneaniline

Based on design and synthesis of salicylideneaniline derivatives (1a-1d), we demonstrate a prototypical system to investigate the excited-state intramolecular charge transfer (ESICT) coupled excited-state intramolecular proton transfer (ESIPT) reaction vi

Extensive spectral tuning of the proton transfer emission from green to red via a rational derivatization of salicylideneaniline

A series of salicylideneaniline derivatives 1a-1f were synthesized under mild condition in high yields, and characterized by 1H NMR, HRMS, UV-vis and emission spectra. In solid and aprotic solvents 1a-1f exist mainly as E conformers that posses

A study of the tautomers of N-salicylidene-p-X-aniline compounds in methanol

We have studied the enol-imine→keto-amine tautomeric equilibrium of N-salicylidene-p-X-aniline compounds with X = Me, OMe, NMe2 as electron donor substituents and X = COMe, CN and NO2 as electron acceptor substituents. The equilibrium constants (Ktauo) and standard thermodynamic properties ΔGtauo, ΔHtauo and ΔStauo were measured and calculated in methanol solution at various temperatures, by means of excitation fluorescence spectroscopy. We have analyzed the p-phenylaniline substitution effect on Ktauo and the thermodynamic properties through the Hammett parameters σ. We have performed molecular orbital calculations at the semiempirical AM1 and ab initio HF/3-21G levels to interpret the experimental results, explicitly including the solute-solvent interaction through the formation of an intermolecular hydrogen bond between the salicylidene and methanol molecules. These computational results show a good correlation with the experimental values. An interpretation of the experimental values of TΔSo, based on changes in the molecular structure produced in the enol-imine→keto-amine tautomeric reaction, is proposed.

Qualitative analysis of the stability of the oxazine ring of various benzoxazine and pyridooxazine derivatives with proton nuclear magnetic resonance spectroscopy

A series of 3,4-dihydro-1,3-benzoxazine and 3,4-dihydro-1,3-pyridooxazine derivatives was synthesized, and the hydrolysis of the derivatives was studied with proton nuclear magnetic resonance spectroscopy. The oxazine derivatives underwent various degrees of hydrolysis when H2O was added to dimethyl sulfoxide solutions of the compounds. The rates and extents of decomposition of the oxazine ring systems depended on the electronic effects of substituents within the molecules. Examination of the proton nuclear magnetic resonance spectra that were generated during decomposition of the oxazines and trends in stability of the oxazine derivatives suggest the formation of an intermediate in the hydrolysis mechanism.