- Synthesis of tetradentate schiff base derivatives of transition bimetallic complexes as antimicrobial agents
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A series of Co(II), Cu(II), Mn(II) and Zn(II) bimetallic complexes have been synthesized with the schiff base ligand 2-(bis-2-hydroxyl phenylidene) diimine (L) derived from the condensation of hydrazine and salicylaldehyde. The synthesized ligand and bimetallic complexes were characterized by different spectroscopic techniques. The characterization of ligand was carried out by FT-IR, H1NMR, C13NMR andMS while the bimetallic complexes were characterized by FT-IR and X-ray crystallographic techniques. The complexes and ligand were employed in vitro for antifungal and antibacterial activities using disc diffusion method. Different fungal strains such as Alternaria Alternate, Aspergillus Flavus and Aspergillus Niger were used to check antifungal activities of bimetallic complexes and ligand. Similarly, the bacterial strains used were Staphylococcus Aureus, Bacillus Subbtilis and Escheria Coli. The biological studies showed that the ligand exhibited lower value of antifungal and antibacterial activities than bimetallic complexes.
- Yousaf, Muhammad,Pervaiz, Muhammad,Sagir, Muhammad,Ashhar-Uz-Zaman,Mushtaq, Muhammad,Naz, Muhammad Yasin
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- Efficient photocatalytic properties of a dinuclear iron complex with bis[2-hydroxybenzaldehyde]hydrazonate ligand
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A novel photooxidative system for degrading toxic organic pollutants is reported. A new complex of Fe2L3(L = bis[2- hydroxybenzaldehyde]hydrazone) synthesized can efficiently activate hydrogen peroxide (H2O2) to oxidize and mineralize the target complexes rhodamine B (RhB) and methyl orange (MO) in aqueous media under ambient temperature and normal pressure and with visible light irradiation.
- Ran, Jing-Wen,Liu, Shao-Wen,Wu, Peng,Pei, Jun
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- Spectroscopic and photophysical properties of salicylaldehyde azine (SAA) as a photochromic Schiff base suitable for heterogeneous studies
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The photochromic cycle of the salicylaldehyde azine (SAA) has been investigated by means of the stationary and time-resolved UV-vis spectroscopy in a number of differently interacting solvents and micellar systems. The primary enol form of this Schiff base is much more energetically stabilized than in the other aromatic Schiff bases, which is reflected in remarkable resistance of SAA to the hydrolysis process. The fluorescence decay measured in highly viscous solvents as well as in micellar systems has proved the existence of different conformers of the cis-keto tautomer. Three different routes of the photochrome (trans-keto tautomer) decay have been also observed.
- Zió?ek, Marcin,Filipczak, Katarzyna,Maciejewski, Andrzej
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- Salicylaldehyde azine cluster formation observed by cold-spray ionization mass spectrometry
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We installed a cold-spray ionization (CSI) source on a mass spectrometer to investigate the self-assembly behavior of an aggregation-induced emission enhancement system. Using a CSI source and the three-dimensional platform, a self-assembly system of a salicylaldehyde azine (SAA) was studied in mixture solution. This method permitted the determination of the structural information of the solution state, which cannot be detected by conventional mass spectrometry. In addition to the [M+H]+ ion (M is the SAA molecule), many major ion clusters such as [2M+Na]+ at m/z 503, [3M+Na] + at m/z 743, [4M+Na]+ at m/z 983 and higher order aggregates were observed in the CSI mass spectra. However, many fragment ions, with the exception of cluster ions, appeared with high abundance when the ESI ion source was used due to the desolvation chamber temperature, suggesting that some aggregation can be detected at low temperatures. To investigate the effect of solvent on the aggregation, the CSI-mass spectrometry (MS) experiments of SAA in absolute ethanol solution and ethanol/water (good/poor solvent) mixture solution were conducted. The most abundant ion peak was protonated SAA (m/z 241) in absolute ethanol, but many cluster ions and some multiple charged ion peaks were observed after adding a small amount of water into the ethanol solution. The results showed good agreement with that inferred by the combinational analysis of scanning electron microscope and fluorescence microscopy, indicating that CSI-MS is capable of providing self-assembly information of labile molecules in the solution state. Copyright
- Xu, Xiangyu,Qiao, Jinping,Deng, Xuebin,Na, Na,Ouyang, Jin
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- New salicylaldehyde azine esters: Structural, aggregation induced fluorescence, electrochemical and theoretical studies
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The establishment of high-tech products relying on organic optoelectronics is focused towards latest strategies for improving the processability and performance. In the present study, two esters of salicylaldehyde azine SAE-F and SAE-NF were synthesized and their structural characterization were performed using FT-IR, 1H and 13C NMR, UV–visible spectroscopy, mass spectrometry and single crystal-XRD technique. The bathochromic shift observed in luminescence measurements from solution to aggregate/solid state, solvent based fluorescence studies, SEM and DLS measurements confirmed the fluorescence emission from the SAE-F aggregates. The DSC data indicated the phase transitions, and the TGA measurements confirmed the thermal stability of SAE-F to withstand temperatures up to 225 °C. The morphological characterization revealed formation of homogeneous pin-hole free uniform films of SAE[sbnd]F. Cyclic voltammetry was used to estimate the HOMO and LUMO energy levels which were found to be ?5.46 eV and ?3.05 eV respectively with a band gap of 2.41 eV. The p-type semi-conductivity of SAE-F was established using hot probe technique. The dielectric measurements were carried out to measure dielectric constant and ac conductivity at different frequency ranges. The electronic data obtained based on Density Functional Theory calculations were in conformity with the experimental results. Successful fabrication of a diode and the recorded current-voltage characteristics clearly advocated SAE-F to be an excellent candidate for electro-optical devices.
- Abdul Salam, Abdul Ajees,Kagatikar, Sneha,Kekuda, Dhananjaya,Kulkarni, Suresh D.,Sunil, Dhanya
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- A simple fluorescent probe for Zn(II) based on the aggregation-induced emission
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A aggregation-induced emission-based fluorescent probe 1 for Zn 2+ was designed and simply synthesized by condensation of salicylaldehyde with aqueous hydrazine. The experimental conditions were first optimized. It was found that N, N-Dimethylformamide (DMF) was the best solvent for the Zn2+-triggered aggregation of compound 1 compared with other solvents. The emission intensity was gradually increased, accompanied by the simultaneous red shift of the maximum emission peak with increasing Zn 2+ concentrations. A red shift about 45 nm was achieved when Zn 2+ concentration is 100 μM. Compared with other Zn2+ fluorescent sensors based on aggregation-induced emission (AIE), compound 1 can detect a lower concentration of Zn2+ with a detection limit of 0.1 μM. Compound 1 also exhibited good selectivity toward Zn2+. The aggregation was verified by the dynamic light scattering (DLS) results, with a Zn2+ concentration-dependent size observed. It was also directly confirmed by TEM analyses.
- Xie, De-Xun,Ran, Zhao-Jin,Jin, Zhen,Zhang, Xiao-Bing,An, De-Lie
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- Simple and sensitive colorimetric sensors for the selective detection of Cu2+ in aqueous buffer
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Simple chromogenic sensor for the selective detection of Cu2+ was described. With the addition of Cu2+, a bathochromic shift about 82 nm was observed in the UV-VIS spectra, with the color change from colorless to bright yellow. This suggested that the coordination between receptor and Cu2+ was formed, and the strong push-pull system occurred. The followed IR spectra indicated that Cu2+ coordinated to the two phenolic oxygen atoms and one of two azomethines in the receptor.
- Huo, Jianzhong,Liu, Kai,Zhao, Xiaojun,Zhang, Xingxing,Wang, Ying
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- Synthesis, X-Ray Structure and In Vitro Cytotoxic Activity of a New Dinuclear Cobalt(III) Complex with Diazine Ligands
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A new dinuclear cobalt(III) compound [Co2 (2,2′-azinodimethyldiphenol)3] has been synthesized, which shows better cytotoxic activity than carboplatin and exhibits potent in vitro antiproliferative activity.
- Li, Fan-fang,Chen, Hong-Yan,Jin, Yi,Zhao, Qi-Hua,Xie, Ming-Jin
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- Highly selective fluorescence turn-on determination of fluoride ions via chromogenic aggregation of a silyloxy-functionalized salicylaldehyde azine
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A novel fluorescent chemsensor TBS-protected salicylaldehyde azine (TSAA) for fluoride ion was developed based on aggregation-induced emission (AIE). The probe TSAA was prepared by the reaction of salicylaldehyde azine (SAA) with tert-butyldimethylsilyl chloride (TBS-Cl) via an unusual synthetic methodology and shows only non-emission. Upon treatment with fluoride in aqueous MeCN solution, the TBS protective group of probe TSAA was removed readily and the fluorescence of the probe was switched on, which resulted in a new fluorescence peak around 543?nm. The fluorescent intensity at 543?nm increases linearly with fluoride ion concentration in the range 1–50?μmol?L?1. This proposed probe shows excellent selectivity toward fluoride ion over other common anions and cations.
- Zhao, Yun-Hui,Li, Yubo,Long, Yunfei,Zhou, Zhihua,Tang, Zilong,Deng, Keqin,Zhang, Shaowei
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- Synthesis, characterization and biological studies of Bis{μ-2,2'-[N,N'- diylbis (nitrilomethylidyne)]diphenolato}dicobalt(II) using triple component solvent system
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The crystal structure of compound [Co2(C14H 12N2O2)2] showed dimeric complex. Two nitrogen atoms and two oxygen atoms of the [N,Nbis( salicylidine)diamine] formed distorted square pyramidal geometry in the region of Co(II) and one oxygen atom from each ligand acting as bridge between two ligand molecules which are distorted in parallel path among each other. The titled complex showed amorphous crystalline structure in toluene solvent but to get more clear X-ray crystallographic data three component solvent system (ethanol, toluene, ethyl acetate) was used. The ligand was synthesized and characterized by FTIR, Mass spectrometry, NMR while the titled complex was characterized by FTIR and X-ray crystallography. The ligand and complex were screened for their antibacterial activity against bacterial species Escheria coli, Staphylococcus aureus and Bacillus subtilis and antifungal activity against A. flavus, A. alternate and A. niger. The activity data shows that the metal complex has more antibacterial and antifungal activities than the synthesized ligand against bacterial strains.
- Yousaf, Muhammad,Pervaiz, Muhammad,Jabbar, Abdul,Zahoor, Ameer Fawad,Bokhari, Tanveer Hussain,Anjum, Anbreen,Sagir, Muhammad,Khan, Misbahul Ain,Ali, Kulsoom Ghulam,Ahmad, Sajjad,Zia-Ur-Rehman, Muhammad,Ashraf, Sadia,Qeureshi, Khurram Shehzad
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- Fluorescence staining of salicylaldehyde azine, and applications in the determination of potassium tert-butoxide
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Salicylaldehyde azine (1), with an aggregation-induced emission (AIE) function, was synthesized from salicylaldehyde and characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high resolution mass spectrometry (HRMS), and X-ray single crystal diffraction. Compound 1 exhibited high thermal stability and good light-emitting behavior in the solid state. It could be preferably used to dye cellulose and KBr. No obvious changes in fluorescence intensity occurred when compound 1 was dissolved in different pH buffer solutions. The addition of TFA led to slight fluorescence quenching, and the fluorescence intensity gradually increased with increasing potassium tert-butoxide solution concentrations. The fluorescence intensity of compound 1 showed a good linear relationship with the concentration of potassium tert-butoxide (0.5–4.0 104 M), y ? 99.193x + 93.599, R2 ? 0.9902; the limit of detection (LOD) was 1.07 107 M. It could measure the content of potassium tert-butoxide with a relative standard deviation (RSD) value of 1.5%.
- Yang, Jinlai,Rui, Jian,Xu, Xu,Yang, Yiqin,Su, Jun,Xu, Haijun,Wang, Yunyun,Sun, Nan,Wang, Shifa
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- Synthesis and spectroscopic investigation of schiff base complexes of lanthanides (III)
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A series of La(III), Pr(III), Nd(III), Sm(III) and Tb(III) complexes have been synthesized with Schiff base (SAZ) derived from the condensation of salicylaldehyde with hydrazine. The prepared Schiff base and its lanthanide complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibilities, UV-visible, IR, 1H NMR, thermal studies and XRD. The complexes have stoichiometry of the type [Ln(SAZ)2·2(H2O)]Cl3, for Pr(III), Sm(III) and Tb(III) where as [Ln(SAZ)2Cl2]Cl for La(III) and Nd(III), where the ligand SAZ coordinates to the lanthanide ion through azomethine nitrogen and phenolic oxygen of azine moiety.
- Rajewar,Dharmale,Pingalkar
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- 2,2'-Azinodimethyldiphenol, C14H12N2O2
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The X-ray single-crystal structure determination of the title compound reveals a trans planar structure in which the molecules stack in columns parallel to the c axis of the unit cell.Each molecule contains intramolecular O...N hydrogen bonds .
- Xu, Xue-Xiang,You, Xiao-Zeng,Sun, Zhen-Fan,Wang, Xin,Liu, Hai-Xin
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- A novel and simple fluorescent chemical sensor SX based on AIE for relay recognition of Zn2+ and Cu2+ in aqueous system and analysis in logic gates
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A simple, fast response and aggregation-induced emission (AIE) fluorescent chemical sensor 2,2′-(hydrazine-1,2-diylidenebis(methaneylylidene))diphenol (SX) based on o-hydroxybenzaldehyde had been designed and synthesized. Interestingly, the increase of water content, the color of the SX solution changed from colorless to bright yellow in solution, and the chemical sensor SX showed the unique AIE properties. The chemical sensor SX exhibited high selectivity and sensitivity to Zn2+ without Cu2+ in DMSO/H2O (4:1, v/v) solution, and the limit of detection was 6. 8 × 10?8 M. In addition, the in situ generated [SX + Zn2+] system was used for the relay detection of Cu2+ without separation and purification and exhibited a new fluorescence quenching signal under the same conditions, and limit of detection [SX + Zn2+] to Cu2+ was 2.3 × 10?8 M. Furthermore, the chemical sensor SX had been successfully applied to detect and analyze Zn2+ and relay detect Cu2+ in environmental water samples.
- Deng, Zhepeng,Ding, Wenmin,Guo, Geng,Jia, Yuehui,Li, Juan,Sun, Yinxia
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- Cascade detection of fluoride and bisulphate ions by newly developed hydrazine functionalised Schiff bases
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Two hydrazine functionalized Schiff bases have been synthesized through the reaction between hydrazine and o-vanillin/salicylaldehyde compounds employing a green-chemical approach and characterized spectroscopically including XRD study. Crystal structure analysis reveals that both the chemosensors, N,N′-bis(o-vanilidine)hydrazine (P17) and N,N′-bis(salicylidene)hydrazine, (HARB) crystallize in monoclinic system with P21/n space group and exist in the locked forms through intramolecular H-bonding (~1.90 ?) between phenolic-OH and N atom of hydrazine. The chemosensors display excellent selectivity towards fluoride followed by bisulphate ions, over other potential competitor anions in acetonitrile. Binding stoichiometry of the individual chemosensor with F? is confirmed to be 1:1 and assessed with absorption study and 1H NMR analysis. Systematic DFT analysis reveals that the contribution of hydroxyl oxygen atoms to the HOMO increases sharply from the chemosensor to chemosensor–F? adduct (17% to 28%) leading to deprotonation of one hydroxyl group and consequently involvement in conjugation impeding the C=N isomerisation. Thus, the hydroxyl proton captured by F? restricts the C=N isomerisation as well as ICT character of both the chemosensors and confirms the cascade sensing mechanism for fluoride and bisulphate ions.
- Roy, Suvojit,Paul, Provakar,Karar, Monaj,Joshi, Mayank,Paul, Suvendu,Choudhury, Angshuman Roy,Biswas, Bhaskar
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- METHODS OF FORMING IMINES, IMINE-RELATED AND IMINE-DERIVED COMPOUNDS USING GREEN SOLVENTS
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The present disclosure relates to using green solvents to synthesize an array of imines, imine-related and imine-derived compounds in an efficient and eco-friendly matter, satisfying green chemistry requirements. Reaction embodiments are performed using solvents, such as ethyl lactate and dimethyl isosorbide, which are both individually characterized as green. In embodiments, solvents include lactic whey and/or water as co-solvents. In these green solvents, the synthesis process discussed herein can produce up to quantitative yields of product at room temperature in a short duration. Embodiments include a method of forming an imine, imine-related or imine-derived compound product. In embodiments, the methods include mixing an aldehyde reactant with a nucleophilic/nitrogen-containing reactant in a green solvent at a temperature between negative twenty degrees Celsius (?20° C.) and positive fifty degrees Celsius (50° C.); stirring the mixture; and forming an imine, imine-related or imine-derived compound product.
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Paragraph 0194-0197
(2021/10/22)
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- Salicylazine activated plasmonic silver nanoprisms for identification of Fe(ii) and Fe(iii) from aqueous solutions
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Herein, we report the synthesis and characterization, along with the successful application, of silver nanoprisms for the identification of Fe(ii)/Fe(iii) at the nanomolar level. A few real samples have also been analyzed successfully. The scanning electron microscopy (SEM)-transmission electron microscopy (TEM) imaging of the sensing events indicate analyte induced changes in the morphology and geometrical pattern of the silver nanoparticles.
- Kumar, Abhay,Singh, Anurag Kumar,Singh, Deovrat,Singh, Raksha,Upadhyay, K. K.,Yadav, Minu
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supporting information
p. 17782 - 17786
(2021/10/12)
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- Synthesis and characterization of hydrazone and azine derivatives of bis(cyclopentadienyI) titanium(IV)
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Pentacoordinated hydrazone and azine derivatives of bis(cyclopentadienyl)titanium(IV) of the type {equation presented}, have been prepared. The products were characterized by chemical analyses, elec- trical conductance, IR, 1H NMR, and electronic spectral studies. Some hydrazone complexes and a few azine com- plexes of titanium have been studied.' ' However, no systematic study on their organometallic derivatives is available. In view of the versatile chelating ability, widespread applications and lack of data involving organometallic derivatives of titanium, it has been considered of interest to study the reactions of Cp2TiCl2 with the title ligands.
- Kaushik, Narender Kumar,Khera, Brij,Sharma, Anand Kumar
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p. 793 - 794
(2021/11/22)
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- Design, synthesis and biological evaluation of Schiff’s base derivatives as multifunctional agents for the treatment of Alzheimer’s disease
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A series of Schiff’s base derivatives was rationally designed, synthesized, and evaluated as multi-function agents for the treatment of Alzheimer’s disease (AD). The results revealed that compound 3b was a novel multifunctional agent. It acted as a highly selective monoamine oxidase-B inhibitor (IC50 = 8.4 nM), which was explained by the docking study. Compound 3b also was an antioxidant agent (2.3 eq) and could significantly inhibit self-induced Aβ1-42 aggregation (31.8%). Meanwhile, compound 3b was a selective metal chelator and could inhibit Cu2+-induced Aβ1-42 aggregation (62.3%). Furthermore, compound 3b presented good neuroprotective effects on H2O2-induced PC12 cell injury. More importantly, compound demonstrated good blood brain barrier permeability and druglike properties. Therefore, compound 3b, a promising multi-targeted active molecule, offers an attractive starting point for further study in the drug-discovery process against AD.[Figure not available: see fulltext.].
- Shi, Jian,Zhou, Yi,Wang, Keren,Ma, Qinge,Wei, Rongrui,Li, Qingfeng,Zhao, Yiyang,Qiao, Zhanpin,Liu, Shuang,Leng, Yumin,Liu, Wenmin,Sang, Zhipei
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p. 624 - 634
(2020/11/30)
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- An activity-based fluorescent probe and its application for differentiating alkaline phosphatase activity in different cell lines
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Herein, a new fluorescent probe, AE-Phos, is reported for detecting the ALP activity with the combined advantages of aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT). Further detailed fluorescence experiments demonstrated that AE-Phos exhibited excellent selectivity and sensitivity, a large Stokes shift, and a fast response towards ALP. Furthermore, AE-Phos was applied to imaging the ALP activity in different cell lines quantitatively. This journal is
- He, Yong,Yu, Junli,Hu, Xiangzi,Huang, Shumei,Cai, Lili,Yang, Liu,Zhang, Huatang,Jiang, Yin,Jia, Yongguang,Sun, Hongyan
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supporting information
p. 13323 - 13326
(2020/11/10)
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- Sensitive and selective detection of uranyl ions based on aggregate-breaking mechanism
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A highly selective fluorescent sensor based on salicylaldehyde azine derivative for the detection of uranyl cation was developed. The aggregation induced emission characteristics of obtained compounds were investigated and a strong emission of these derivatives was observed upon aggregation in organoaqueous solvent. The emission of these aggregated forms was found to be effectively quenched by uranyl cation. The effect of uranyl was shown to be destructive rather than constructive to the aggregation of the salicylaldehyde azine derivatives. An aggregate-breaking process was proposed to explain the destruction of the aggregates by the complexation with uranyl cation. The sensor showed good selectivity towards uranyl and with a low detection limit up to ppb scale, hence, can be used as an efficient fluorescent sensor for detecting uranyl cation in aqueous solvent.
- Pham, Xuan-Qui,Kumar, Naresh,Ha-Thi, Minh-Huong,Leray, Isabelle
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p. 139 - 145
(2019/01/19)
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- Method for preparing fluorescent probe based on salicylaldehyde azine as well as application of fluorescent probe
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The invention discloses a method for preparing a fluorescent probe based on salicylaldehyde azine as well as application of the fluorescent probe. The method comprises the following steps: weighing hydrazine hydrate, adding the hydrazine hydrate into a round-bottom flask, adding absolute ethanol and stirring uniformly; continuously adding salicylic aldehyde into the round-bottom flask and stirringat constant temperature to obtain a crude product; filtering the crude product, cooling and crystallizing under the condition of room temperature, and removing a solvent through reduced-pressure suction filtration to obtain a solute crystal; and drying the solute crystal at room temperature, adding ethyl acetate and recrystallizing to obtain a yellow needle-shaped compound salicylaldehyde azine.The probe salicylaldehyde azine is prepared through a one-step synthesis method; the test result in a water and acetonitrile system with different volume ratio indicates that the molecule has high aggregation fluorescence enhanced (AIE) property; in the mixed system of the acetonitrile and the water, the fluorescent probe has high recognition ability on copper ions; furthermore, the fluorescent probe has high selectivity on the copper ions, has low detection limit and can serve as a probe for efficiently recognizing the copper ions.
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Paragraph 0032-0037
(2019/01/23)
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- Glucose:urea:NH4Cl low melting mixture for the synthesis of symmetric azines
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Alternate reaction media have become very important due to the problems created by the highly volatile nature of the solvents. The deep eutectic mixture is a kind of an alternate reaction medium which has emerged in recent years. Low melting mixtures were introduced by making the deep eutectic mixture more cost-effective and renewable by introducing carbohydrates into it. The properties of low melting mixtures include easiness to prepare, usage of low-cost components, biodegradability, solubility in water, easy separation from organic compounds, etc. The low melting mixtures such as glucose:urea:NH4Cl, glucose:ChCl, glucose:urea:ChCl, glycerol:urea:NH4Cl, and ethylene glycol:urea:NH4Cl were used in different ratios for the reactions. The properties such as viscosity, density, acidity, glass transition temperature, and thermal stability were studied. An unusual method for the synthesis of symmetrical azines is introduced wherein benzaldehyde and hydroxylamine are reacted in the presence of glucose:urea:NH4Cl. The method of synthesis needs only less reaction time, temperature and the product was easily separated. The products were confirmed using GC-MS and NMR techniques. The recyclability of glucose:urea:NH4Cl was studied.
- Theresa, Letcy V.,Shaibuna,Sreekumar
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p. 3148 - 3160
(2019/09/03)
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- Unprecedented synthesis of symmetrical azines from alcohols and hydrazine hydrate using nickel based NNN-pincer catalyst: An experimental and computational study
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Azines are having widespread applications in both industry as well as synthetic chemistry. Thus new catalytic synthetic protocols are desirable as they are greener alternatives than traditional methods of synthesis. Thus, herein a novel earth abundant nickel based NNN-pincer catalyst Ni(BPEA)(Cl2) is synthesized for the first time for the direct transformation of alcohols and hydrazine hydrate into symmetrical azines. This catalytic reaction is accompanied by dehydrogenative coupling of alcohols and hydrazine hydrate and is carried out in presence of a base. Theoretical calculations supported by experimental evidence have been performed for understanding the mechanistic insights of the reaction.
- Shiekh, Bilal Ahmad,Kaur, Damanjit,Godara, Sachin Kumar
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- Subtle structural variation in azine/imine derivatives controls Zn2+ sensitivity: ESIPT-CHEF combination for nano-molar detection of Zn2+ with DFT support
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Excited-state intra-molecular proton transfer (ESIPT)-active imine and azine derivatives, structurally characterised by XRD, and denoted L1, L2, L3 and L4, possess weak fluorescence. The interaction of these probes with Zn2+ turns ON the fluorescence to allow its nano-molar detection. Among the four ESIPT-active molecules, L2, L3 and L4 are bis-imine derivatives while L1 is a mono-imine derivative. Among the three bis-imine derivatives, one is symmetric (L3) while L2 and L4 are unsymmetrical. The lowest detection limits (DL) of L1, L2, L3 and L4 for Zn2+ are 32.66 nM, 36.16 nM, 15.20 nM and 33.50 nM respectively. All the probes bind Zn2+ (105 M-1 order) strongly. Computational studies explore the orbital level interactions responsible for the associated photo-physical processes.
- Khanra, Somnath,Ta, Sabyasachi,Ghosh, Milan,Chatterjee, Sudeshna,Das, Debasis
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p. 21302 - 21310
(2019/07/22)
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- A New Alternative Synthesis of Salicylaldazine via Microwave Irradiation Method
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Two diazine Schiff base ligands, HLa and HLb, derived from thiocarbohydrazide and salicylaldehyde derivatives were synthesized using the microwave-assisted synthesis approach. The confirmation of both ligands was elucidated through physiochemical and spectroscopy techniques as well as single X-ray crystallography diffraction. The analyses showed that the ligands synthesized were formed as azine instead of thiocarbohydrazone based on the missing thione, C=S moiety, throughout FTIR and NMR spectrascopic data. This finding was further concluded by X-ray crystal analysis. The biological properties of these ligands were screened using the disc diffusion method. The result shows that HLb shows significant inhibition towards all of the bacteria tested.
- Kassim, Karimah,Hamali, Muhamad Azwan,Yamin, Bohari
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- Excited state intramolecular single proton transfer mechanism of pigment yellow 101 in solid state: Experiment and DFT calculation
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To investigate fluorescence mechanism of Pigment Yellow 101 (P. Y. 101) in solid state, three aromatic aldehyde azines (1–3) including P. Y. 101 have been synthesized and compared with each other. Results indicated that P. Y. 101 prepared by solvothermal method is actually the mixture of two polymorphs, whose molecular packing mode can be transformed into each other by recrystallizing or external stimuli such as pressure and grinding. The ESIPT properties of 1–3 were investigated by DFT/TD-DFT calculations and time-correlated single photon counting (TCSPC) technique. Both experimental and theoretical results revealed that the dual fluorescence properties of P. Y. 101 in solid state are ascribed to the excited-state intramolecular single proton transfer fluorescence emissions of two structurally different polymorphs rather than the results of the sequential or concerted excited-state intramolecular double proton transfers, which provide a potential valuable tool for developing multistimuli-responsive luminescent materials.
- Shen, Shen,Liu, Xian,Sun, Jianqi,Wang, Mingda,Jiang, Zhengjun,Xia, Guomin,Wang, Hongming
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- Li+-Induced fluorescent metallogel: A case of ESIPT-CHEF and ICT phenomenon
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A fluorescent metallogel (1percent w/v) has been synthesized from non-fluorescent ingredients viz. the smallest possible low molecular weight aromatic symmetrical ligand H2SA (1) and LiOH in a chloroform and methanol mixture. The chelation of Li+ is not only responsible for the inhibition of excited state intramolecular proton transfer (ESIPT) or the origin of fluorescence through chelation enhanced fluorescence (CHEF) in 1, but also for aggregation leading to gelation. The metallogel obtained from 1/Li+ reveals a fibrous morphology while 1 with other, bigger size, alkali metal ions like Na+/K+/Cs+ demonstrates the growth of crystals with different shapes. The effect of the size of the alkali metal ion over gel formation is well explored by FTIR, UV-vis, fluorescence, average lifetime measurements, SEM and PXRD. The metallogel shows multi-stimuli responsive behaviour towards thermal and mechanical stress as well as reswelling properties. The regioisomer H2PBA (2) also shows emission upon treatment with LiOH due to the presence of intramolecular charge transfer (ICT), this is well established by various experiments. The mechanism of gel formation is well established by FTIR, 1H NMR, UV-vis, fluorescence, lifetime measurements, SEM and single crystal and powder XRD instrumental techniques. The involvement of various phenomena in gel formation has been further supported by other synthesized model compounds viz. H2MBA (3), PMO (4), H2SEA (5) and H2SPA (6). True gel phase material is proved by detailed rheological experiments.
- Dixit, Manish Kumar,Dubey, Mrigendra
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p. 23762 - 23772
(2018/09/29)
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- Tunable Color of Aggregation-Induced Emission Enhancement in a Family of Hydrogen-Bonded Azines and Schiff Bases
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A simple synthesis strategy afforded a family of hydrogen-bonded azines and Schiff-bases. Although in dilute solution these dyes are faint light emitters, all exhibit bright luminescence upon aggregation. Changing the peripheral substituents from electron donating to electron withdrawing allows emission fine-tuning in a range from bluish-green to orange-red. The crystal structures of the materials reveal that the restriction of intramolecular rotations is the main mechanism for the aggregation-induced emission enhancement properties.
- Guieu, Samuel,Cardona, Francisco,Rocha, Jo?o,Silva, Artur M. S.
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supporting information
p. 17262 - 17267
(2018/11/10)
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- C[sbnd]N bond formation in alicyclic and heterocyclic compounds by amine-modified nanoclay
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In the current protocol, amine functionalized montmorillonite K10 nanoclay (NH2-MMT) was applied to catalyze the formation of C[sbnd]N bonds in the synthesis of azines and 2-aminothiazoles at room temperature. In comparison with the current methods of C[sbnd]N bond formation, this approach displays specific advantages include atom economy, clean conversion, design for energy efficiency, the use of nontoxic and heterogeneous catalyst, higher purity and yields, safer solvent and reagents for this organic transformation.
- Zarnegar, Zohre,Alizadeh, Roghayeh,Ahmadzadeh, Majid,Safari, Javad
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- Efficient and versatile catalysis for β-alkylation of secondary alcohols through hydrogen auto transfer process with newly designed ruthenium(II) complexes containing ON donor aldazine ligands
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A new series of ruthenium(II) carbonyl complexes, [RuCl(CO)(EPh3)2(L1-2)] (1–4) (E?=?P or As; H2L1?=?salicylaldazine, H2L2?=?2-hydroxynaphthaldazine), have been assembled from ruthenium(II) precursors [RuHCl(CO)(EPh3)3] and bidentate ON donor Schiff base ligands (H2L1-2). Both ligands and their new ruthenium(II) complexes have been characterized by elemental analyses, spectroscopic methods (UV, IR, NMR (1H, 13C, 31P) as well as ESI mass spectrometry. The molecular structures of H2L1 and 1 have been confirmed by single crystal X-ray diffraction. Based on the above studies, an octahedral coordination geometry around the metal center has been proposed for 1–4. To investigate the catalytic effectiveness of 1–4, the complexes have been used as catalysts in β-alkylation of secondary alcohols with primary alcohols and synthesis of quinolines. The effect of solvent, time, base, catalyst loading, and substituent of the ligand moiety on the reaction was studied. Notably, 1 was a more efficient catalyst toward alkylation of a wide range of alcohols and quinolines synthesis. The reusability of the catalyst was checked and the results showed up to six catalytic runs without significant loss of activity.
- Premkumar, Periyasamy,Manikandan, Rajendran,Nirmala, Muthukumaran,Viswanathamurthi, Periasamy,Malecki, Jan Grzegorz
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p. 3065 - 3079
(2017/10/11)
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- Structure and electronics in dimeric boron π expanded azine and salphen complexes
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Although boron-based fluorophores incorporating nitrogenous chelating ligands have received much attention, there has been little work on examples of boron-salphen and azine derivatives. In this report, we present several π expanded boron salphen type complexes, incorporating both bis(2-hydroxynaphthaldehyde)azine as well as ortho, meta and para variants of the analogous 2-hydroxynaphthaldehyde salphen compounds. For the azine, we observed only the formation of a single BF2 adduct, while for the naphth-phen compounds dimeric BF2 binding was observed. All new compounds were fully characterized via X-ray diffraction, and both DFT and TDDFT studies were carried out to probe the electronic structures of these fluorophores.
- Crandall, Laura A.,Dawadi, Mahesh B.,Burrell, Tailon,Odoom, Adwoa,Ziegler, Christopher J.
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p. 627 - 632
(2017/07/07)
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- Synthesis, Characterization, and Biological Activity of Organotin(IV) Complexes with Schiff Bases
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The synthesized Schiff base ligands H2L1, N,N'-bis(2-hydroxybenzylidene)1,2-diaminobenzene, and H2L2, N,N'-bis(2-hydroxybenzylidene)hydrazine, reacted with Alk2SnCl2 to give organotin(IV) complexes 1–10. The products were characterized by elemental analysis, FTIR, 1H and 13C NMR, and mass spectrometry. All organotin(IV) derivatives with [O,N,O] donor ligands retained their 5-coordinated geometry in solid state and solutions. Most of synthesized complexes exhibited significant antibacterial activity. Cytotoxicity was also tested by using the brine shrimp (Artemia salina) lethality bioassay.
- Nazneen,Ali,Shahzadi,Shujah
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p. 2970 - 2978
(2018/02/21)
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- Fluorine ion detection probe based on aggregation-induced emission as well as preparation method and application of fluorine ion detection probe
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The invention discloses a fluorine ion detection probe based on aggregation-induced emission as well as a preparation method and application of the fluorine ion detection probe. The structure of a fluorescent probe is shown as a formula (I); the fluorescent probe is formed by taking salicylic aldehyde as a raw material, forming salicylic aldehyde azine through the raw material and hydrazine hydrate and carrying out silicon protection. The probe disclosed by the invention has stable optical performances, high fluorine ion detection sensitivity and low detection lower limit; the detection limit is 1mu.M and a response range is 1mu.M to 50mu.M. The fluorine ion detection probe has good selectivity and no response on negative and positive ions including chlorine ions, bromine ions, iodate ions, periodate ions, nitrate ions, nitrite ions, acetate ions, carbonate ions, sulfate ions, sulfite ions, silver ions, barium ions, calcium ions, lithium ions, magnesium ions, ammonium ions, nickel ions, zinc ions and the like. The fluorine ion detection probe has the advantages of simple synthesis, moderate conditions and high yield. The fluorescent molecular probe has an actual application value in the fields of biochemistry and environmental chemistry, especially detection of fluorine ions in water and the like. (The formula (I) is shown as the description.).
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Paragraph 0048-0050
(2017/07/07)
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- A family of silatrane-armed triazole-encapped salicylaldehyde-derived Schiff bases: Synthesis, spectral analysis, and antimicrobial and quantum chemical evaluation
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This work describes the successful synthesis of salicylaldehyde-derived Schiff base-linked organosilicon compounds following a highly efficient click approach. Hydroxyl-terminated Schiff bases were alkylated to bis-acetylenes (1–3) which upon 3?+?2 cycloaddition with 3-azidopropyltriethoxysilane yielded triazole-decorated bis-silanes (4–6). These silanes further underwent base-catalyzed transesterification to afford Schiff base-linked triazole-bound organosilatranes (7–9). The final silatranes as well as precursor alkynes and silanes were comprehensively characterized using NMR (1H and 13C) and infrared spectroscopic techniques together with elemental analysis and mass spectrometry of compounds 7–9. Also, the structures of alkynes 1–3 and silatrane 7 were validated using single-crystal X-ray crystallography. Organosilatranes were initially screened for their pharmacokinetic profile using absorption, distribution, metabolism, excretion and toxicity (ADMET) tools and then explored for their antimicrobial activities, with compound 9 emerging as the most potent antimicrobial agent. Compounds 1–3 and 7–9 also underwent thorough computational analysis by applying the density functional theory (DFT) approach with B3LYP/6-31G(d) level of theory and the results were found to be consistent with the experimental data. Several DFT-based descriptors were also evaluated providing a valuable insight into molecular stability and reactivity.
- Singh, Gurjaspreet,Arora, Aanchal,Rani, Sunita,Kalra, Pooja,Aulakh, Darpandeep,Wriedt, Mario
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- Tungsten hexachloride nanoparticles loaded on montmorillonite K-10: a novel solid acid catalyst in the synthesis of symmetrical and unsymmetrical azines
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In the present investigation, we have developed a novel technique to prepare azines using nano-WCl6 loaded on Montmorillonite K10 clay as a highly active catalyst. A variety of aldehydes and ketones were efficiently converted to the corresponding azines using catalytic amounts of nanosized WCl6/Mont. K10 under mild conditions. The nanostructures of WCl6 loaded on Mont. K10 as solid acid catalyst have been prepared by solid dispersion method. The advantages of this catalyst are rapid completion of the reactions, simplicity of performance, lack of pollution and mild and green reaction conditions. The morphologies, structure, and chemical components of parent and modified clay were successfully characterized using SEM, FT-IR, CV, XRD and EDX measurements.
- Safari, Javad,Gandomi-Ravandi, Soheila,Shariat, Saeedeh
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p. 1499 - 1507
(2016/07/06)
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- Improvement in Titanium Complexes Bearing Schiff Base Ligands in the Ring-Opening Polymerization of L-Lactide: A Dinuclear System with Hydrazine-Bridging Schiff Base Ligands
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A series of titanium (Ti) complexes bearing hydrazine-bridging Schiff base ligands were synthesized and investigated as catalysts for the ring-opening polymerization (ROP) of L-lactide (LA). Complexes with electron withdrawing or steric bulky groups reduced the catalytic activity. In addition, the steric bulky substituent on the imine groups reduced the space around the Ti atom and then reduced LA coordination with Ti atom, thereby reducing catalytic activity. All the dinuclear Ti complexes exhibited higher catalytic activity (approximately 10-60-fold) than mononuclear LCl-H-TiOPr2 did. The strategy of bridging dinuclear Ti complexes with isopropoxide groups in the ROP of LA was successful, and adjusting the crowded heptacoordinated transition state by the bridging isopropoxide groups may be the key to our successful strategy.
- Tseng, Hsi-Ching,Chen, Hsing-Yin,Huang, Yen-Tzu,Lu, Wei-Yi,Chang, Yu-Lun,Chiang, Michael Y.,Lai, Yi-Chun,Chen, Hsuan-Ying
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p. 1642 - 1650
(2016/02/27)
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- Unusual Aggregation/Gelation-Induced Phosphorescence of Propeller-Type Binuclear Platinum(II) Enantiomers
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Three binuclear cyclometalated PtIIcomplexes, [(ppy)Pt(μ-SA)Pt(ppy)] (ppy = 2-phenylpyridine, SA: salicylaldehyde azine), have been synthesized and characterized. Owing to the blockage of the intramolecular rotation of the bridging SA ligands, all three complexes exhibit propeller-type enantiomers and aggregation-induced phosphorescence (AIP). Interestingly, one complex with –NEt2groups instead of long alkyl chains, amide, urea peptides, cholesterol, sugar, or steroidal groups was found to show strong phosphorescence enhancement gated by the gelation process. This unusual gelation behavior is rarely encountered, as the metallogel has no intermolecular hydrogen bonding or Pt–Pt interactions. We attribute the driving force of this gelation-induced phosphorescence (GIP) to the propeller-type structure, optimally balanced solubility of –NEt2groups, enantiomer-induced π–π stacking interactions, and strong multiple intermolecular H–C, H–O, and H–H interactions.
- Gou, Fei,Cheng, Jinghui,Zhang, Xiaohong,Shen, Guangyu,Zhou, Xiangge,Xiang, Haifeng
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supporting information
p. 4862 - 4866
(2016/10/26)
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- Synthesis of 2-Amino-4-(3-amino-5-hydroxy-4 H -pyrazol-4-ylidene)-4 H -chromene-3-carbonitriles
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A simple and efficient protocol was developed for the synthesis of 2-amino-4-(3-amino-5-hydroxy-4H-pyrazol-4-ylidene)-4H-chromene-3-carbonitriles by the potassium phosphate-catalyzed reaction of salicylaldehydes, malononitrile, and 2-cyanoacetohydrazide in ethanol. The method offers advantages such as a simple workup procedure and good yields. When the method was extended to two equivalents of 2-cyanoacetohydrazide instead of malononitrile, the unexpected formation of a salicylaldehyde azine was observed, leading to a novel route for the synthesis of salicylaldehyde azines.
- Mane, Mansing M.,Pore, Dattaprasad M.
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supporting information
p. 1720 - 1724
(2016/07/06)
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- Photoactivatable aggregation-induced emission fluorophores with multiple-color fluorescence and wavelength-selective activation
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Photoactivatable (caged) fluorophores are widely used in chemistry, materials, and biology. However, the development of such molecules exhibiting photoactivable solid-state fluorescence is still challenging due to the aggregation-caused quenching (ACQ) effect of most fluorophores in their aggregate or solid states. In this work, we developed caged salicylaldehyde hydrazone derivatives, which are of aggregation-induced emission (AIE) characteristics upon light irradiation, as efficient photoactivatable solid-state fluorophores. These compounds displayed multiple-color emissions and ratiometric (photochromic) fluorescence switches upon wavelength-selective photoactivation, and were successfully applied for photopatterning and photoactivatable cell imaging in a multiple-color and stepwise manner.
- Peng, Lu,Zheng, Yue,Wang, Xiaoyan,Tong, Aijun,Xiang, Yu
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supporting information
p. 4326 - 4332
(2015/03/14)
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- Ratiometric fluorescent pH probes based on aggregation-induced emission-active salicylaldehyde azines
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A series of luminescent salicylaldehyde azines (SAs) containing different electron-accepting substituents (-NO2, -F, and -Cl), electron-donating substituents (-OMe and -NEt2), and a π-extended system (naphthalene ring) are prepared for the application of fluorescent pH probes. These SAs inheriting the aggregation-induced emission (AIE) features display strong blue, green, and red fluorescence with large Stokes shifts in water and solid medium. Combining the advantages of AIE and the chemical reactivity of phenol towards OH-/H+, most of the SAs can be used as ratiometric fluorescent pH probes with a broad pH range (2-14) in water and solid medium (test paper). Moreover, the inherent relationship between their chemical structures and AIE properties/pKa values (7.5-13.3) is studied, which provides unequivocal insights into the design of AIE-active dyes and their applications. This journal is
- Ma, Xiaofeng,Cheng, Jinghui,Liu, Jiaoyan,Zhou, Xiangge,Xiang, Haifeng
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p. 492 - 500
(2015/02/02)
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- A fluorescent light-up probe based on AIE and ESIPT processes for β-galactosidase activity detection and visualization in living cells
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A novel fluorescent probe SA-βGal is reported here with light-up response to β-galactosidase. SA-βGal possesses the β-galactopyranoside group to react with β-galactosidase and releases the fluorescent salicylaldehyde azine with both aggregation induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics. The linear fluorescent response enables the in vitro quantification of β-galactosidase activity in a range of 0-0.1 U mL-1 with a detection limit of 0.014 U mL-1. The probe exhibits significant advantages, such as no self-quenching at high concentrations, a large Stokes shift (190 nm) and high specificity to β-galactosidase with an excellent light-up ratio of 820 fold. Moreover, thanks to its good retention in living cells, the application of SA-βGal for the imaging of cellular β-galactosidase was also achieved with high contrast.
- Peng, Lu,Gao, Meng,Cai, Xiaolei,Zhang, Ruoyu,Li, Kai,Feng, Guangxue,Tong, Aijun,Liu, Bin
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p. 9168 - 9172
(2015/12/08)
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- A fluorescent light-up platform with "aIE + ESIPT" characteristics for multi-target detection both in solution and on paper strip
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We report a fluorescent light-up platform for multi-target detection in aqueous solution and on paper strip. The platform is based on a salicylaldazine fluorogen with aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) characteristics, which shows distinct advantages including ease of chemical modifications, free of self-quenching effect, excellent light-up ratio and large Stokes shift. To demonstrate the versatility of the platform, palladium cation and perborate anion, as well as UV light, were selected as the targets. The three representative probes, AIE-Pd, AIE-perborate and AIE-UV, light up specifically in the presence of the target both in aqueous solution and on paper strip. The immediate naked-eye response makes the probes ideal for instrument-free and power-free detection. This journal is
- Zhang, Ruoyu,Gao, Meng,Bai, Shiqiang,Liu, Bin
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p. 1590 - 1596
(2015/03/04)
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- Solvent-free, [Et3NH][HSO4] catalyzed facile synthesis of hydrazone derivatives
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In the present study, a library of hydrazone analogues 2(a-j) and 4(a-e) were synthesized, which were typically accessed via a solvent-free facile nucleophilic addition between hydrazine hydrate and appropriately substituted aromatic aldehydes 1(a-j) and 3-formylchromones 3(a-e). The molecular structure of compound (2f) was well supported by single crystal X-ray crystallographic analysis and also verified by DFT calculations. This new synthetic, eco-friendly, sustainable protocol resulted in a remarkable improvement in the synthetic efficiency (90-98% yield), high purity, using [Et3NH][HSO4] as a catalyst and an environmentally benign solvent eliminating the need for a volatile organic solvent and additional catalyst. This ionic liquid is air and water stable and easy to prepare from cheap amine and acid. The present methodology is a green protocol offering several advantages such as, excellent yield of products, minimizing production of chemical wastes, shorter reaction profile, mild reaction conditions, simple operational procedure, easy preparation of catalyst and its recyclability up to five cycles without any appreciable loss in catalytic activity. The optimization conditions carried out in the present study revealed that 20 mol% of ionic liquid catalyst under solvent-free condition at 120°C are the best conditions for the synthesis of hydrazone derivatives in excellent yields.
- Parveen, Mehtab,Azaz, Shaista,Malla, Ali Mohammed,Ahmad, Faheem,Da Silva, Pedro Sidonio Pereira,Silva, Manuela Ramos
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p. 469 - 481
(2015/02/19)
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- Selective electrochemical determination of trace level copper using a salicylaldehyde azine/MWCNTs/Nafion modified pyrolytic graphite electrode by the anodic stripping voltammetric method
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A novel Cu2+ electrochemical sensor based on a salicylaldehyde azine/MWCNTs/Nafion-modified pyrolytic graphite electrode was prepared for anodic stripping analysis of Cu2+. Salicylaldehyde azine was synthesized and then used for the selective determination of the heavy metal pollutant Cu2+ due to its azine structure, which gave selective complexing ability toward Cu2+. The use of MWCNTs with their strong adsorption ability could greatly enhance the sensitivity. Nafion, a proton-exchange polymer, was used as the conductive matrix in which the salicylaldehyde azine and MWCNTs could be strongly fixed to the substrate electrode surface. The as-prepared electrochemical sensor showed remarkably enhanced selectivity and sensitivity towards Cu2+. The response current of the sensor was linear with Cu2+ concentration ranging from 5 to 300 nM under 15 min accumulation at open-circuit potential, with a very low detection limitation of about 1 nM. The hybrid functionalized electrode also exhibited good selectivity to avoid the interference of other heavy metal ions like Cd2+, Pb2+ and Hg2+ in the mixture solution together with Cu2+. Real application towards environmental sample analysis confirmed that the modified electrode could be applied for the selective determination of trace levels of Cu2+ in the Yellow River.
- Liao, Yuan,Li, Qian,Yue, Ying,Shao, Shijun
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p. 3232 - 3238
(2015/02/05)
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- An expeditious synthetic approach towards the synthesis of Bis-Schiff bases (aldazines) using ultrasound
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Aldazines (Bis-Schiff bases) 1-24 were synthesized using aromatic aldehydes (heterocyclic and benzaldehydes) and hydrazine hydrate under reflux using conventional heating and/or via ultrasound irradiation using BiCl3 as catalyst. Ultrasonication conditions with cat. BiCl3 proved to be an effective, environmentally friendly synthetic procedure. This methodology is robust in the presence of electron donating and electron withdrawing groups affording desired products with high yields (>95%) in just a couple of minutes vs. hours using conventional heating.
- Khan, Khalid M.,Jamil, Waqas,Ambreen, Nida,Taha, Muhammad,Perveen, Shahnaz,Morales, Guillermo A.
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p. 1200 - 1205
(2014/02/14)
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- Anomalous reaction of hydrazine hydrate with 5-arylidene barbiturates: Formation of benzalazines
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Reaction of 5-arylidene barbiturates (3a-i) with hydrazine hydrate resulted in the unusual formation of novel benzalazines (5a-i) in 70-90% yield rather than the expected pyrazole fused pyrimidines.
- Goudgaon,Upendar Reddy, Ch.,Patil, Sharanabasappa,Sheshikant
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p. 277 - 282
(2019/01/21)
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- Comparative studies of structural, thermal, optical, and electrochemical properties of azines with different end groups with their azomethine analogues toward application in (opto)electronics
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Two series of azines and their azomethine analogues were prepared via condensation reaction of benzaldehyde, 2-hydroxybenzaldehyde, 4-pyridinecarboxaldehyde, 2-thiophenecarboxaldehyde, and 4-(diphenylamino) benzaldehyde with hydrazine monohydrate and 1,4-phenylenediamine, respectively. The structures of given compounds were characterized by FTIR, 1H NMR, and 13C NMR spectroscopy as well as elemental analysis. Optical, electrochemical, and thermal properties of all compounds were investigated by means of differential scanning calorimetry (DSC), UV-vis spectroscopy, stationary and time-resolved photoluminescence spectroscopy, and cycling voltammetry (CV). Additionally, the electronic properties, that is, orbital energies and resulting energy gap were calculated theoretically by density functional theory (DFT). Influence of chemical structure of the compounds on their properties was analyzed.
- Sek, Danuta,Siwy, Mariola,Bijak, Katarzyna,Grucela-Zajac, Marzena,Malecki, Grzegorz,Smolarek, Karolina,Bujak, Lukasz,Mackowski, Sebastian,Schab-Balcerzak, Ewa
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p. 10320 - 10332
(2013/11/06)
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- The reaction of ethyl 2-oxo-2H-chromene-3-carboxylate with hydrazine hydrate
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Although salicylaldehyde azine (3) was reported in 1985 as the single product of the reaction of ethyl 2-oxo-2H-chromene-3-carboxylate (1) with hydrazine hydrate, we identified another main reaction product, besides 3, which was identified as malono-hydrazide (4). In the last two decades, however, some articles have claimed that this reaction afforded exclusively hydrazide 2 and they have reported the use of this hydrazide 2 as a precursor in the syntheses of several heterocyclic compounds and hydrazones 6. We reported herein a study of the formation of 2 and a facile route for the synthesis of the target compounds N'-arylidene-2-oxo-2H-chromene-3-carbohydrazides 6a-f.
- Abdel-Aziz, Hatem A.,Elsaman, Tilal,Attia, Mohamed I.,Alanazi, Amer M.
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p. 2084 - 2095
(2013/04/23)
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- Novel de-acylative ring opening of 3-acetyl and 3-bromo acetyl coumarins
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Reaction of 3-acetyl and 3-bromoacetyl coumarins with hydrazine hydrate has resulted in the ring opening of the coumarin moiety. The reaction was attempted with a view to obtain some new pyridazinones and pyrazolones. The reaction did not proceed via the expected pathway instead led to the formation of salicyl azines, the structure of which has been confirmed by single crystal X-ray studies.
- Yaragatti, Naazneen B.,Kulkarni, Manohar V.,Kumar, Gudibande N. A.,Gururow, Tayur N.
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p. 594 - 597,4
(2020/09/15)
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- Synthesis of 1H-indazole: A combination of experimental and theoretical studies
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A new practical synthesis of 1H-indazole is presented. A previous mechanism for the cyclization step is proved to be nonfeasible and a hydrogen bond propelled mechanism is proposed. The new mechanism is suitable for similar cyclization, and a new reaction is predicted. Springer Science+Business Media B.V. 2012.
- Chen, Xinzhi,Zhou, Shaodong,Qian, Chao,He, Chaohong
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p. 1619 - 1628
(2012/10/30)
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- Facile method for the conversion of semicarbazones/thiosemicarbazones into azines (Under Microwave Irradiation) and oxadiazoles (By Grinding)
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In an effective transformation, semicarbazones/thiosemicarbazones are smoothly converted into azines under microwave irradition. Oxadiazoles are also obtained from semicarbazones by reaction with bromine generated in situ via a grinding reaction in the solid phase. Taylor &Francis Group, LLC.
- Chattopadhyay, Gautam,Ray, Partha Sinha
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p. 2607 - 2614
(2011/08/07)
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