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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Physical Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: DFT,Nucleophilicity,N-Heterocyclic,Stannylenes
- چکیده:
- چکیده انگلیسی: Substitution effects are probed for novel N-heterocyclic stannylenes (NHSns), including 1,4-di(R)-tetrazole-5-stannylenes (1R), and 1,3-di(R)-tetrazole-5-stannylenes (2R), using B3LYP/6-311++G** level of theory. Nucleophilicity, multiplicity, and stability of 1R and 2R are calculated; with R = H, methyl, ethyl, i-propyl, t-butyl, Ph, OH, methoxy, NO2, CN and CF3. Asymmetric 2H appears more nucleophilic (N ̴ 4) than its corresponding symmetric 1H isomer (N ̴ 3), mostly due to the formers higher separation of charge. The N is more sensitive to electronic effects in 1R stannylenes than those in the 2R series. Electron donating R groups increase N with Hammett ρ constants of -3.3 and -2.7 for 1R and 2R, respectively. Stannylene 2H is slightly more aromatic (NICS (1) = -10.31) than 1H (NICS (1) = -10.25). Every 1R is more stable than its corresponding 2R isomer. Every 2R is generally more nucleophilic and aromatic than its corresponding 1R. In addition the former is less electrophilic with a larger band gap and narrower stannylene bond angle. Substituent effects are probed on N by devising proper isodesmic reactions. The trend for N is: 2t-buthyl> 2iso-propyl> 2ethyl> 2methyl> 2ph> 2OMeth >1t-buthyl> 2OH> 2H >1Ph> 1iso-propyl> 1OH >1ethyl >1methyl >1OMeth >1H >2CF3 >2NO2> 2CN> 1CF3> 1CN> 1NO2.
- انتشار مقاله: 29-11-1397
- نویسندگان: Amir Hosein Zamanzadeh,Nazanin Mohebi,Mohammad Zaman Kassaee,Peter Cummings,Kun Dong
- مشاهده
- جایگاه : پژوهشی
- مجله: Physical Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Density functional theory,N-Heterocyclic plumbylenes,Nucleophilicity,Singlet-triplet energy gaps,Substituent effects
- چکیده:
- چکیده انگلیسی: Plumbylenes are reactive intermediates whose discovery and characterizations are of great significance. Here, ten novel plumbylenes are introduced and characterised. A comparison is made between novel 1,4-di(R)tetrazol-5-plumbylenes (IR) with their corresponding 1,3-di(R) isomers (IIR), at DFT (R = H, Me, Et, i-Pro, and t-Bu). Every one of our plumbylenes (IR or IIR) appears less stable, with a lower band gap (ΔΕHOMO-LUMO), and a higher nucleophilicity (N) than its corresponding carbene (I´R or II´R). For both IR and IIR plumbylenes the trend of N values emerges consistent with the size of substituents (t-Bu > i-Pro > Et > Me > H). Every IIR shows a higher N than its corresponding IR. Except IIH, every IIR emerges more aromatic than its related IR. The N of both IR and IIR appears directly proportional to the size of R, proton affinity (PA), and plumbylene bond angles (N—((Pb) ̈ ) ̂—N); while it is inversely proportional to electrophilicity (ω), and ΔΕHOMO-LUMO.
- انتشار مقاله: 12-04-1396
- نویسندگان: Nazanin Mohebi,Mohammad Zaman Kassaee
- مشاهده
- جایگاه : پژوهشی
- مجله: Nanochemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Antibacterial activity,Staphylococcus aureus,Escherichia coli,Arc discharge,Ethylene propylene rubber (EPR),Silver nanopowder
- چکیده:
- چکیده انگلیسی: Following our interest in reaching for a molded rubber article with possible detergent contact applications, durable silver nanopowder (AgNP) is synthesized by arc discharge, then mixed with varying ratios of ethylene propylene rubber (EPR), affording novel AgNP@EPR nanocomposites. X-ray diffraction (XRD) patterns of AgNP as well as AgNP@EPR show no trace of impurity, while scanning electron microscopy (SEM) indicates an average diameter of 50 nm for the former. Transmission electron microscopy (TEM) images while confirm the SEM results, show quite a few 5 nm AgNP particles lying beside some micro crumbs. Our DC arc discharge technique involves explosion of movable silver anode and static cathode by a current pulse between 5 to 10 A cm-2. A solution blending method is employed for preparation of AgNP@EPR nanocomposites. The AgNP is first dispersed in toluene using an ultrasonic homogenizer, and then thoroughly mixed with EPR in the same solvent whose removal gives nanocomposites of 2, 4, 6 and 8 vol% AgNP in EPR, showing strong antibacterial activity against both Escherichia coli and Staphylococcus aureus.
- انتشار مقاله: 08-08-1393
- نویسندگان: Marzieh Miranzadeh,Mohammad Zaman Kassaee,Leila Sadeghi,Mohsen Sadroddini,Mehdi Razzaghi Kashani,Nima Khoramabadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Advanced Journal of Chemistry-Section A
- نوع مقاله: Journal Article
- کلمات کلیدی: Adsorption,ARSENIC,photocatalyst,Magnetic nanocomposite,Ag Nanoparticles
- چکیده:
- چکیده انگلیسی: As (III) regularly requires oxidation to As (V), before it can be removed from water. Here, we reported photocatalytic removal of As (III) as well as adsorption of As (III) and As (V) using a novel, porous magnetic Ag/TiO2/Fe3O4@GO nanocomposite which was characterized via FT-IR, XRD, SEM, and TEM. A mathematical model (the central composite design) was used to estimate the relationship between the observed adsorption and our set of variables including initial concentration of arsenic ions, adsorbent dosage, pH, and the contact time. An optimum adsorption capacity of about 91% was observed for As (III) using 20 mg adsorbent with 24 ppm initial concentration of As (III), at pH = 5, within 90 min, and room temperature. Likewise, an optimum adsorption capacity of about 87% was observed for As (V) using 11 mg adsorbent with 17 ppm initial concentration of As (V), at pH = 3, within 30 min, and room temperature. The electrostatic factors between surface charge of nanocomposite and arsenic species were used to explain adsorption behavior of As (III) and As (V) at different conditions. The Langmuir isotherm equations best interpreted the nature of adsorption of As (III) and A (V). It was found during phocatalytic process maximum R% was about 63% for As (III) using 40 mg photocatalyst.
- انتشار مقاله: 08-07-1398
- نویسندگان: Marzieh Miranzadeh,Fahime Afshari,Behnoosh Khataei,Mohammad Zaman Kassaee
- مشاهده