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1.
Wail Al Zoubi Abbas Ali Salih Al‐Hamdani Susan Duraid Ahmed Young Gun Ko 《Journal of Physical Organic Chemistry》2018,31(2)
The new Schiff base 1‐[(2‐{1‐[(dicyclohexylamino)‐methyl]‐1H‐indol‐3‐yl}‐ethylimino)‐methyl]naphthalen‐2‐ol (HL) was prepared from 1‐{[2‐(1H‐Indol‐3‐yl)‐ethylimino] methyl}‐naphthalen‐2‐ol and dicyclohexyl amine. From this Schiff base, monomeric complexes [M (L)n (H2O)2 Cl2] with M = Cr, Fe, Mn, Cd, and Hg were synthesized and characterized based on elemental analysis (EA), FT‐IR, mass(MS), UV‐visible, thermal analysis, magnetic moment, and molar conductance. The results showed that the geometrical structural were octahedral geometries for the Cr(III) and Fe(III) complexes, square planer for Pd(II) complex, and tetrahedral for Mn(II), Cd(II), and Hg(II) complexes. Kinetic parameters such as ΔE*,ΔH*, ΔG*, and K of the thermal decomposition stages were calculated from the TGA curves using Coats‐Redfern method. Additionally, density functional theory (DFT) was applied for calculations of both electronic structure and spectroscopic properties of synthesized Schiff base and its complexes. The analysis of electrostatic potential (EPS) maps correlates well with the computed energies providing on the dominant electrostatic nature of N‐H‐‐‐O interactions. The biological activities had been tested in vitro against Staphylococcus aureus, Pseudomonas aeruginosa, as well fungi like Penicillium expansum, Fusarium graminearum, Macrophomina phasealina, and Candida albicans bacteria in order to assess their antimicrobial potential. 相似文献
2.
A theoretical study of antioxidant activity of some Schiff bases derived from biologically important phenolic aldehydes and phenylenediamines
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Romesh Borgohain Jyotirekha G. Handique Ankur Kanti Guha Sanjay Pratihar 《Journal of Physical Organic Chemistry》2018,31(2)
Because of their numerous biological as well as industrial importance, the study of Schiff bases is an emerging field for the researchers, in recent time. In this study, we have designed some Schiff bases derived from biologically important precursors. The antioxidant activities of the designed compounds are thoroughly studied theoretically using density functional theory taking various parameters like bond dissociation enthalpy, ionization enthalpy, proton dissociation enthalpy, and electron transfer enthalpy followed by the study of effects of solvent, spin density, and molecular orbital on antioxidant activity of the compounds. The comparison of antioxidant activity of the compounds with that of phenol and their parent aldehydes reveals the superior antioxidant activity of the designed compounds. This study contributes towards the information of an important bridge between bioorganic and computational chemistry. 相似文献
3.
Synthesis and luminescence properties of novel 4-(N-carbazole methyl) benzoyl hydrazone Schiff bases
4-(N-carbazole methyl) benzoyl hydrazine was synthesized on the basis of carbazole, and then nine novel carbazolyl acylhydrazone Schiff bases were synthesized by the condensation reaction between 4-(N-carbazole methyl) benzoyl hydrazine and the substituted benzaldehydes. The relationships between the substituted group types and the UV fluorescence spectral properties, as well as the fluorescence quantum yields of the title Schiff bases were also investigated. The results show that the introduction of both the donating and accepting electron groups causes various grade redshifts of the fluorescence characteristic emission peak of the title Schiff bases to occur.The fluorescence quantum yields of the title Schiff bases with the donating group are increased, and the highest fluorescence quantum yield is up to 0.703. 相似文献
4.
Lei Tian Pengfei Shi Jieying Wu Yufang Zhou Minghua Jiang 《Journal of luminescence》2007,127(2):423-430
The title compounds, several Schiff bases with D-π-D type have been successfully synthesized from reaction of 4-(N-dialkylamino) benzaldehyde and hydrazine or p-phenylenediamine in ethanol. These compounds were characterized by IR, 1H NMR, elemental analysis and electronspray mass spectrometry. One-photon fluorescence and two-photon fluorescence properties have been investigated. The two-photon absorption (TPA) cross section (σ) of these compounds was obtained by using the open-aperture Z-scan technique. Based on theoretical calculations and factual test, the influence that a series of substituted groups and the conjugated frame imposed on TPA cross section were systematically discussed. 相似文献
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Huang Mei Huang Min Wang Xiu Duan Wen-Gui Lin Gui-Shan Lei Fu-Hou 《Molecular diversity》2022,26(1):125-136
Molecular Diversity - A series of novel acyl thiourea compounds containing gem-dimethylcyclopropane ring were designed and synthesized by multi-step reactions in search of novel antifungal... 相似文献
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Mohammad Taghi Sharbati Mohammad Navid Soltani Rad Somayeh Behrouz Farzin Emami 《Journal of luminescence》2011,131(4):553-558
Fabrications of a single layer organic light emitting diodes (OLEDs) based on two conjugated acceptor-donor-acceptor (ADA) isatin Schiff bases are described. The electroluminescent spectra of these materials range from 630 to 700 nm and their band gaps were measured between 1.97 and 1.77 eV. The measured maximum external quantum efficiencies (EQE) for fabricated OLEDs are 0.0515% and 0.054% for two acceptor-donor-acceptor chromophores. The Commission International De L’Eclairage (CIE) (1931) coordinates of these two compounds were attained and found to be (0.4077, 0.4128) and (0.4411, 0.4126) for two used acceptor-donor-acceptor chromophores. The measured I-V curves demonstrated the apparent diode behavior of two ADA chromophores. The turn-on voltages in these OLEDs are directly dependent on the thickness. These results have demonstrated that ADA isatin Schiff bases could be considered as promising electroluminescence-emitting materials for fabrication of OLEDs. 相似文献
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A. Filarowski A. Kochel M. Kluba F. S. Kamounah 《Journal of Physical Organic Chemistry》2008,21(11):939-944
The synthesis and X‐ray measurements of four Schiff bases were carried out at 100 K. The HOMA and HOSE aromaticity indices were estimated on the basis of the experimental data. The aromaticity of the phenyl ring and the chelate chain was analysed. A comparison of the aromaticity of naphthalene and phenyl derivatives of hydroxy aryl Schiff bases is presented. The balance between the aromaticity of adjacent rings of the naphthalene fragment and its effect on proton transfer is defined. Research on the interrelations between aromaticity and the intramolecular proton transfer in hydroxy aryl Schiff bases is shown. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Turan Nevin Buldurun Kenan Türkan Fikret Aras Abdulmelik Çolak Naki Murahari Manikanta Bursal Ercan Mantarcı Asim 《Molecular diversity》2022,26(5):2459-2472
Molecular Diversity - Schiff bases are well-known compounds for having significant biological properties. In this study, a new Schiff base ligand and its metal complexes were synthesized, and their... 相似文献
12.
A. A. Vashchenko L. S. Lepnev A. G. Vitukhnovskii O. V. Kotova S. V. Eliseeva N. P. Kuz’mina 《Optics and Spectroscopy》2010,108(3):463-465
It is studied how the introduction of various substituents into the composition of organic ligands affects the photoluminescence
spectra of new zinc(II) complexes with tetradentate Schiff bases H2L (derivatives of salicylic aldehyde (H2SAL1, H2SAL2) and o-vanillin (H2MO1, H2MO2) with ethylenediamine and o-phenylenediamine) in the form of bulk solids and thin films. It is demonstrated that the emission spectra of bulk solid complexes
without o-phenylenediamine bridges (ZnSAL1 and ZnMO1) contain additional long-wavelength bands compared to the spectra of corresponding
thin films. In the case of films obtained from [ZnSAL1]2 dimer complexes, the long-wavelength band is dominant. At the same time, the photoluminescence spectra of ZnSAL2 and ZnMO2
complexes with o-phenylenediamine bridges are similar in the case of solid samples and thin films. The electroluminescent properties of organic
light-emitting diodes (OLEDs) with the ITO/α-NPD/ZnL/Ca:Al structure are studied. The bathochromic shift of the electroluminescence
peaks of OLEDs with respect to the photoluminescence spectra of bulk solid samples and thin films is probably related to the
formation of exciplexes at the α-NPD/ZnL interface. The electroluminescence spectra of OLEDs based on [ZnSAL1]2 show a hypsochromic shift of the emission maximum, which can be caused by a shift of the recombination region into the α-NPD
layer. 相似文献
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Molecular Diversity - In the present study, 14 novel naphthyridine-11-amine derivatives were synthesized and their inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase... 相似文献
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Jelena Đorović Zoran Marković Zorica D. Petrović Dušica Simijonović Vladimir P. Petrović 《Molecular physics》2017,115(19):2460-2468
The time-dependent density functional theory (TDDFT) was applied in conjunction with the natural bond orbital analysis to examine the UV-Vis properties of 10 phenolic Schiff bases. The calculations were performed with different functionals, but main discussion refers to results obtained at the B3LYP/6-311+G(d,p) level of theory. The approach based on the natural localised molecular orbital clusters indicates similar behaviour for majority of examined compounds. The HOMO (“highest occupied molecular orbital”) cluster is delocalised over the ring which is electron richer, the HOMO-1 cluster is spread over the other ring, whereas the LUMO (“lowest unoccupied molecular orbital”) cluster is situated on the imino group. The two bands at long wavelengths correspond to the HOMO → LUMO and HOMO-1 → LUMO transitions, i.e. from both A and B rings to the imino group. The next band originates from a transition from the imino group to the imino group. The band at the smallest wavelengths originates from a transition from the A ring to the A ring, or from the B ring to the B ring. Our findings are in very good agreement with the existing literature data. 相似文献
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Schilf W Kamieñski B Szady-Chelmieniecka A Grech E 《Solid state nuclear magnetic resonance》2000,18(1-4):97-105
Two Schiff bases; N, N′-bis(5-bromosalicylidene)-1,2-diaminoethane, BS, and 7-[(1-{5-bromo-2-hydroxyphenyl} methylidene)amino]-4-methylcoumarin, Sc, and two appropriate Schiff–Mannich bases, N, N′-bis{5-bromo-3-[(diethylamino)methyl]salicylidene}-1,2-diaminoethane, BSM, and 7-[(1-{5-bromo-3-[(diethylamino)methyl]-2-hydroxyphenyl} methylidene)amino]-4-methylcoumarin, SMc, capable of intramolecular hydrogen bonding have been investigated by multinuclear magnetic resonance methods in both solid and liquid phases. In all of the compounds under investigation tautomeric equilibrium involving an intramolecular hydrogen bond has been found. The Schiff–Mannich bases, which can form two different kinds of H bonds at room temperature, form relatively weak H bonds with the imino nitrogen atoms. At low temperatures the tautomeric proton exchange becomes slow on the NMR time scale and both hydrogen-bonded forms can be observed by 1H, 13C, and 15N NMR methods. In the solid state the tautomeric process is frozen and only one H-bonded form is present. On the basis of 13C and 15N CPMAS NMR spectra this is identified as the form with hydrogen bonds involving the imino groups. This conclusion is in good agreement with previous results obtained by X-ray diffraction methods.
The investigated Schiff bases (BS and Sc) form relatively weak H bonds. The proton position in the hydrogen bridge, estimated from 15N and 13C chemical shifts, is very similar in both the solution and solid phases. In chloroform solution the observed tautomeric equilibria are almost insensitive to a temperature change within the range 223 to 303 K. 相似文献
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最近从葡萄酒中鉴定并分离出两种苹果酸(MA)结构类似物:2-异丙基苹果酸(2-IPMA)和3-异丙基苹果酸(3-IPMA).使用密度泛函理论(DFT)评估了MA, 2-IPMA和3-IPMA的构象和抗氧化相关热力学性质,结果显示,2-IPMA和3-IPMA的C2羟基具有较高的自由基清除活性.基于大多数抗氧化剂的单线态比三线态更稳定,预测2-IPMA和3-IPMA将分别在气相条件下通过双氢原子转移(dHAT),顺序双质子损失双电子转移(SdPLdET)和双电子转移质子转移(dET-PT)方式参与自由基清除途径,形成4-甲基-3-氧代戊酸和3-甲基-2-甲酰丁酸.根据低能量消耗优先原则,2-IPMA和3-IPMA优先清除自由基的途径依次为:HAT, ET-PT和SPLET.计算结果证实了当前研究的假设,并表明就反应焓热力学数据而言,两种MA类似物的抗氧化能力有利于HAT途径. 相似文献
18.
Yu Zhao Li-ping Xu Jun Tong Yong-qiang Li Li-xia Xiong Fang Li Li-na Peng Zheng-ming Li 《Molecular diversity》2012,16(4):711-725
In searching for environmentally benign insecticides with high activity, low toxicity and low residue, two series of novel anthranilic diamide containing methyl ether and isopropyl ether group were designed and synthesized. All of the compounds were characterized by 1H NMR spectroscopy, 13C NMR spectroscopy and elemental analysis. The single crystal structure of 19j was determined by X-ray diffraction. The insecticidal activities of the new compounds were evaluated. The results showed that some compounds exhibited excellent insecticidal activities against Lepidoptera pests. Among this series, compound, 18l showed 100?% larvicidal activity against Mythimna separate Walker, Plutella xylostella Linnaeus and Laphygma exigua Hubner at the test concentration, which was equal to the available chlorantraniliprole. 相似文献
19.
Atul T. Manvar Raghuvir R. S. Pissurlenkar Vijay R. Virsodia Kuldip D. Upadhyay Dinesh R. Manvar Arun K. Mishra Hrishikesh D. Acharya Alpesh R. Parecha Chintan D. Dholakia Anamik K. Shah Evans C. Coutinho 《Molecular diversity》2010,14(2):285-305
In continuation of our research program on new antitubercular agents, this article is a report of the synthesis of 97 various symmetrical, unsymmetrical, and N-substituted 1,4-dihydropyridines. The synthesized molecules were tested for their activity against M. tuberculosis H 37Rv strain with rifampin as the standard drug. The percentage inhibition was found in the range 3–93%. In an effort to understand the relationship between structure and activity, 3D-QSAR studies were also carried out on a subset that is representative of the molecules synthesized. For the generation of the QSAR models, a training set of 35 diverse molecules representing the synthesized molecules was utilized. The molecules were aligned using the atom-fit technique. The CoMFA and CoMSIA models generated on the molecules aligned by the atom-fit method show a correlation coefficient (r 2) of 0.98 and 0.95 with cross-validated r 2(q 2) of 0.56 and 0.62, respectively. The 3D-QSAR models were externally validated against a test set of 19 molecules (aligned previously with the training set) for which the predictive ${r^{2} (r^{2}_{\rm pred})}$ is recorded as 0.74 and 0.69 for the CoMFA and CoMSIA models, respectively. The models were checked for chance correlation through y-scrambling. The QSAR models revealed the importance of the conformational flexibility of the substituents in antitubercular activity. 相似文献