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11.
The rational design of small building block molecules and understanding their molecular assemblies are of fundamental importance in creating new stimuli-responsive organic architectures with desired shapes and functions. Based on the experimental results of light-induced conformational changes of four types of triangular azo dyes with different terminal functional groups, as well as absorption and fluorescence characteristics associated with their molecular assemblies, we report that aggregation-active emission enhancement (AIEE)-active compound (1) substituted with sterically crowded tert-butyl (t-Bu) groups showed approximately 35% light-induced molecular switching and had a strong tendency to assemble into highly stable hexagonal structures with AIEE characteristics. Their sizes were regulated from nanometer-scale hexagonal rods to micrometer-scale sticks depending on the concentration. This is in contrast to other triangular compounds with bromo (Br) and triphenylamine (TPA) substituents, which exhibited no photoisomerization and tended to form flexible fibrous structures. Moreover, non-contact exposure of the fluorescent hexagonal nanorods to ultraviolet (UV) light led to a dramatic hexagonal-to-amorphous structure transition. The resulting remarkable variations, such as in the contrast of microscopic images and fluorescence characteristics, were confirmed by various microscopic and spectroscopic measurements. 相似文献
12.
Synthesis and Cytotoxic Evaluation of Novel 1,2,3‐Triazole‐4‐Linked (2E,6E)‐2‐Benzylidene‐6‐(4‐nitrobenzylidene)cyclohexanones 下载免费PDF全文
Mohammad Mahdavi Maryam Akhbari Mina Saeedi Maryam Karimi Niloufar Foroughi Elahe Karimpour‐Razkenari Heshmatollah Alinezhad Alireza Foroumadi Abbas Shafiee Tahmineh Akbarzadeh 《Helvetica chimica acta》2016,99(3):175-180
This work describes the synthesis of novel 1,2,3‐triazole‐4‐linked (2E,6E)‐2‐benzylidene‐6‐(4‐nitrobenzylidene)cyclo‐hexanones starting from cyclohexanone. 1‐(Cyclohex‐1‐en‐1‐yl)piperidine, the enamine from cyclohexanone and piperidine, reacted with 4‐nitrobenzaldehyde to obtain 2‐(4‐nitrobenzylidene)cyclohexanone. Condensation of the latter compound with (prop‐2‐yn‐1‐yloxy)benzaldehyde derivatives under acidic conditions gave (4‐nitrobenzylidene)‐[(prop‐2‐yn‐1‐yloxy)‐benzylidene]cyclohexanones. Finally, ‘click reaction’ of these derivatives and various organic azides led to the title compounds. All compounds were examined by MTT assay for cytotoxic activity in one human breast cancer cell line, MDA‐MB‐231. 相似文献
13.
H. K. Barrenscheen Margarete Frey F. Feigl L. T. Fairhall M. Settimj D. Ganassini A. Necke H. Müller Ch. Badham H. B. Taylor G. Moillère F. Weyrauch St. Litzner F. Grendel N. Schoorl H. Begemann A. Berat G. Widmark B. Vahlquist E. M. P. Widmar S. L. Oerskov J. P. Gregersen P. Iversen H. W. Mook D. D. van Sluke W. M. Kirjan W. C. Stadie E. C. Ross K. Lang H. Waelsch Gertrud Klepetar I. St. Lorant L. Kopetz J. W. Heim W. W. Práwdicz-Neminski Z. Babitsch J. F. Reith Th. von Fellenberg R. G. Turner Mina Z. Weeks A. Castille V. Henri 《Analytical and bioanalytical chemistry》1934,98(3-4):147-160
14.
In this study density functional theory (DFT) calculations at B3LYP/6-31G(d), B3LYP/6-31+G(d) and B3LYP/6-311+G(2df,2p) levels for geometry optimization and total energy calculation were applied for investigation of the important energy-minimum conformations and transition-state of 1,2-, 1,3-, and 1,4-dithiepanes. Moreover, ab initio calculations at HF/6-31G(d) level of theory for geometry optimization and MP2/6-311G(d)//HF/ 6-31G(d) level for a single-point total energy calculation were reported for different conformers. The obtained results reveal that, the twist-chair conformer is a global minimum for all of these compounds. Also, two local minimum were found in each case, which are twisted-chair and twisted-boat conformers. The boat and chair geometries are transition states. The minimum energy conformation of 1,2-dithiepane is more stable than the lowest energy forms of 1,3-dithiepane and 1,4-dithiepane. Furthermore, the anomeric effect was investigated for 1,3-dithiepane by the natural bond orbital method. The computational results of this study shows that all conformers of 1,3-dithiepane have a hypercojugation system. Finally, the 13C NMR chemical shifts for the conformers of 1,4-dithiepane were calculated, which have good correlation with their experimental values. 相似文献
15.
Issa Yavari Mina Haghdadi Rahebeh Amiri 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2015-2023
Ab initio calculations at HF/6-31+G? level of theory for geometry optimization, and MP2/6-31+G?//HF/6-31+G? and B3LYP/6-31+G?//HF/6-31+G? levels for a single-point total energy calculation, are reported for the chair and twist conformations of 1,2-dithiane (1), 3,3,6,6-tetramethyl-1,2-dithiane (2), 1,2,4,5-tetrathiane (3), and 3,3,6,6-tetramethyl-1,2,4,5-tetrathiane (4). The C2 symmetric chair conformations of 1 and 2 are calculated to be 21.9 and 8.6 kJ mol?1 more stable than the corresponding twist forms. The calculated energy barriers for chair-to-twist processes in 1 and 2 are 56.3 and 72.8 kJ mol?1, respectively. The C2h symmetric chair conformation of 3 is 10.7 kJ mol?1 more stable than the twist form. Interconversion of these forms takes place via a C2 symmetric transition state, which is 67.5 kJ mol?1 less stable than 3-Chair. The D2 symmetric twist-boat conformation of 4 is calculated to be 4.0 kJ mol?1 more stable than the C2h symmetric chair form. The calculated strain energy for twist to chair process is 61.1 kJ mol?1. 相似文献
16.
Determination of Trichloroacetic Acid (TCAA) Using CdO Nanoparticles Modified Carbon Paste Electrode
In this paper, the electrochemical behavior of a carbon paste electrode modified with CdO nanoparticles as a potential electrocatalyst for the reduction of trichloroacetic acid (TCAA) was investigated using cyclic voltammetry and double‐potential step chronoamperometry. The modified electrode showed a great enhancement in cathodic peak current with respect to reduction of TCAA in acidic aqueous solution. Using this increment, a quantitative method was developed for the determination of TCAA in aqueous solution. The detection limit and linear dynamic range of TCAA are 2.3×10?6 M and 2.3×10?4–3×10?6 M, respectively. 相似文献
17.
Novel 1,2,3,4‐Tetrahydroquinazolinones via Reaction of 2‐Amino‐N‐substituted Benzamides and Dimethyl Acetylenedicarboxylate 下载免费PDF全文
Semiramis Nahavandian Sadegh Allameh Mina Saeedi Shirin Ansari Mohammad Mahdavi Alireza Foroumadi Abbas Shafiee 《Helvetica chimica acta》2015,98(7):1028-1033
Reaction of 2‐amino‐N‐substituted benzamides and dimethyl acetylenedicarboxylate (DMAD) in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in H2O at room temperature led to the formation of novel 1,2,3,4‐tetrahydroquinazolinones. 相似文献
18.
Zahra Najafi Mohammad Mahdavi Maliheh Safavi Mina Saeedi Heshmatollah Alinezhad Mahboobeh Pordeli Sussan Kabudanian Ardestani Abbas Shafiee Alireza Foroumadi Tahmineh Akbarzadeh 《Journal of heterocyclic chemistry》2015,52(6):1743-1747
New derivatives of triazole‐isoxazole were synthesized through a four‐step reaction starting from various ethyl 4‐aryl‐2,4‐dioxobutanoate derivatives. Finally, all compounds were examined by MTT assays for cytotoxic activity in two human breast cancer cell lines (MCF‐7 and T‐47D). 相似文献
19.
Novel polyimides obtained from a new aromatic diamine (BAPO) containing pyridine and 1,3,4‐oxadiazole moieties for removal of Co(II) and Ni(II) ions 下载免费PDF全文
Novel, thermally stable polyimides (PIs) containing a 1,3,4‐oxadiazole and pyridine moieties based on a new aromatic diamine 2,5‐bis‐(aminopyridine‐2‐yl)‐1,3,4‐oxadiazole, BAPO, were synthesized. The prepared polymers were soluble in dimethysulfoxide (DMSO) and concentrated sulfuric acid at room temperature as well as in polar and aprotic solvents, such as, N‐methylpyrrolidone (NMP) and N,N‐dimethylacetamide (DMAc) at elevated temperature. Thermal behaviors of the PIs were studied by thermogravimetric analysis/dynamic thermal analysis (TGA‐DTA) and differential scanning calorimetry (DSC). The inherent viscosities of the PI solutions were in the range of 0.38–0.61 dl/g (in DMSO with a concentration of 0.125 g/dl at 25 ± 0.5°C). The removal of Co(II) and Ni(II) ions from aqueous solutions was performed using polymer 6, which was obtained from BAPO and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA). The maximum adsorption capacity was observed for Co(II) ion at pH = 7.0 (110.4 mg g?1, 1.87 mmol g?1). Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
20.
Mohammad Ali Rasouli Mohammad Mahdavi Parviz Rashidi Ranjbar Mina Saeedi Abbas Shafiee Alireza Foroumadi 《Tetrahedron letters》2012,53(52):7088-7092
This work describes a green and efficient one-pot synthesis of N-alkyl-2-(2-oxoazepan-1-yl)-2-arylacetamide derivatives via an Ugi four-center, three-component reaction of 6-aminohexanoic acid, aromatic aldehydes, and isocyanide derivatives in water under reflux conditions in the absence of a catalyst. 相似文献