Original Research Article
Physical chemistry
Ali Esmaeili; Reza Fazaeli; Esmat Mohammadi Nasab
Abstract
Preliminary researches provided essential information about the optimized configuration of triatomic XO2 (X = O, S, Se, Te) systems, which were bent in the ground state and linear in their first excited state. The Jahn-Teller effects including the Jahn-Teller (JTE), the Renner-Teller effect (RTE), and ...
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Preliminary researches provided essential information about the optimized configuration of triatomic XO2 (X = O, S, Se, Te) systems, which were bent in the ground state and linear in their first excited state. The Jahn-Teller effects including the Jahn-Teller (JTE), the Renner-Teller effect (RTE), and the pseudo Jahn–Teller effect (PJTE) are parts of the most important reasons for structural distortion in the high symmetry configurations for each molecular system. This study purpose was to investigate the dependence between PJT parameters including the vibronic coupling constant values (F), energy gap between reference states (Δ), and initial force constant (K0). In all above mentioned molecules, stability were increased with the reduction in the symmetry level. This increment was attributed to the PJTE. The vibronic coupling interaction between the ground (Σg), and the first excited states (Πu) through the PJTE problem (PJT (Σg+ Πu) × Πu) was because of the asymmetry and molecules bending phenomenon. The hardness difference parameter Δ[η (C2V) -η (D∞h)] decreases from O to Te (30.42, 22.66, 22.65, 22.58 Kcal/mol). These changes could explain the trend, which were observed for the D∞h → C2V conversion process.
Original Research Article
Analytical chemistry
Esmat Shojaei; Mahboubeh Masrournia; Ali Beyramabadi; Hossein Behmadi
Abstract
Chromium has been widely applied in industrial of pigment, stainless steel and electroplating and tanning procedure that enters the water sources. In this work, a simple and reproducible potentiometric sensor was developed for the determination of Cr(III) ions in real solid samples. For this purpose, ...
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Chromium has been widely applied in industrial of pigment, stainless steel and electroplating and tanning procedure that enters the water sources. In this work, a simple and reproducible potentiometric sensor was developed for the determination of Cr(III) ions in real solid samples. For this purpose, a new Schiff base (4-((E)-(2-amino-4 chlorophenylimino) methyl) -5-(hydroxymethyl)-2-methylpyridin-3-ol) were synthesized based on a chemical methods and utilized as a novel and sensitive ionophore for the preparation of Cr(III)-carbon paste electrode. Percentage of carbon paste electrode composition including, graphite powder, ionophore, paraffin oil as a binder, and graphene oxide(GO), was optimized with a chemometric approach using a central composite design method. The optimum percentage of ionophore and nanomaterial in the electrode was obtained 15%w/w. The predicted slope by the computational method and the obtained slope by the experimental method for the proposed sensor was not significantly different. The sensor was linear in the range of 1×10-10- 1×10-2 M for the determination of Cr(III).The effects of other parameters such as pH, response time, lifetime, and interfering ions were studied with one factor at the time method in the optimal composition of the sensor. Proper range of pH, lifetime and response time were acquired 3.5-9.0, 8 weeks and 10 s, respectively. The essential advantages of the proposed sensor were the suitable linear range, a wide range of pH, proper sensor stability, and fast response for the Cr(III) determination. Finally, the analytical application of prepared sensor evaluated to determine Cr(III) in waste and tap water samples.
