کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5417626 | 1506948 | 2008 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A computational study of the conformations of the boric acid (B(OH)3), its conjugate base ((HO)2BOâ) and borate anion (B(OH)4â)
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
The conformations of boric acid (1), its conjugate basis (2) and borate anion (3) have been investigated with the B3LYP, HF, MP2 and QCISD methods with a variety of basis sets. Transition-state structures connecting the various minima have been computed. Relative energies are reported at the G3(MP2)//B3LYP level of theory. The lowest-energy conformation of boric acid has C3h symmetry. The Cs conformer lies 4.1Â kcal/mol higher in energy and the barrier for inter-conversion is 7.8Â kcal/mol. The lowest-energy conformation of (HO)2BOâ has C2v symmetry. There are two conformations lying higher in energy by 1.7 and 9.1Â kcal/mol, with barriers of 7.8 and 10.3Â kcal/mol, respectively. For borate anion two distinct S4-symmetry minima were located which differ in energy by 1.5Â kcal/mol. The computed enthalpies of formation for 1, 2 and 3 are â236.3, â242.9 and â320.8Â kcal/mol, respectively.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 853, Issues 1â3, 31 March 2008, Pages 33-38
Journal: Journal of Molecular Structure: THEOCHEM - Volume 853, Issues 1â3, 31 March 2008, Pages 33-38
نویسندگان
Demetris Stefani, Ioannis Pashalidis, Athanassios V. Nicolaides,