کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10275865 | 463405 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Experimental evidence of formation of imines in the course of reduction of hydrazones
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
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چکیده انگلیسی
The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen-nitrogen bond followed by a reduction of the carbon-nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pHÂ <Â 2. This has been interpreted as due to differences in slopes dE1/2/dpH and pKa-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current-voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6-8 the reduction of the imine IV takes place in a single two-electron step, at pH 8-12 in two one-electron steps. Final proof of the initial cleavage of the N-N bond is presented by comparison with the reduction of nitrones.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electroanalytical Chemistry - Volume 581, Issue 2, 1 August 2005, Pages 284-293
Journal: Journal of Electroanalytical Chemistry - Volume 581, Issue 2, 1 August 2005, Pages 284-293
نویسندگان
M.S. Baymak, H. Celik, H. Lund, P. Zuman,