کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5418713 | 1506968 | 2007 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Computational predictions regarding ultrafast bond breakage and conformational changes in aliphatic chloro-amines
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
In a series of TD-DFT calculations we have investigated the homolytic cleavage of N-Cl and C-Cl bonds in protonated and neutral aliphatic amines on the ground- and excited-state potential energy surfaces. Our focus is to address the possibility of ultrafast bond breakage and the further processes that the resulting N and C based radicals can undergo. The S1n â Ï* states of the N-chloro-amines are repulsive whereas the S1 states of the N-(chloroalkyl)-amines are bound Rydberg states. On the S1 states of the N-chloro-amines the possibility therefore exists for ultrafast formation of N-based radicals. This state is conveniently located for a femtosecond resolved pump-probe study at 266 nm. An analysis of the conformers of the resulting radicals shows that - except in the N-protonated δ-alkyl radical - there is no driving force to induce a conformational change in the radicals. The driving force in the N-protonated δ-alkyl radical is most likely an interaction between the N-H bond and the radical site that has been shown to be important in amine radical cations [S. Hammerum, C.B. Nielsen, J. Phys. Chem. A 109 (2005) 12046]. The calculations could be taken to indicate that it is likely for a conformational change to take place in simple aliphatic amines; in this case all of the lowest excited states are Rydberg states and the excited-state amine therefore resembles a ground state radical cation in which the conformational change is believed to occur.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 811, Issues 1â3, 1 June 2007, Pages 117-124
Journal: Journal of Molecular Structure: THEOCHEM - Volume 811, Issues 1â3, 1 June 2007, Pages 117-124
نویسندگان
Rasmus Y. Brogaard, Theis I. Sølling,