CHEMICAL SHIELDING OF DOPED NITROGEN ON C20 CAGE AND BOWL FULLERENES
F.R. Nikmaram, A. Khoddamzadeh
Islamic Azad University, Tehran, Iran
Nikmaram88@iausr.ac.ir
Ключевые слова: C (cage), C (bowl), nitrogen doping, NMR
Страницы: 180-184
Аннотация
The C20 (cage), C20 (bowl), C20H10 (bowl) fullerene structures and their nitrogen doped derivatives such as C20NH (cage), C20NH (bowl), C20H10N (bowl), C20H10NH (bowl) are fully optimized at the MPW1PW91/6-31G level of theory. The natural atomic charge comparison shows that in C20H10N (bowl), the nitrogen atom with about -0.58 has a more negative charge with respect to other nitrogen doped structures. The nuclear magnetic resonance chemical shielding is evaluated for nitrogen doped structures and the neighbors connected to nitrogen, C6, and C7 atoms. The nitrogen atom doped on carbon sites of C20H10N (bowl) has the largest shielding isotropic shifts to the upper field (-203.58 ppm). This means that the electron density around nitrogen in the C20H10N (bowl) structure is higher. Interestingly, there is a significant correlation between the charges and siso values of nitrogen and carbon atoms (C6 and C7). Namely, as the charge becomes more negative, siso shifts to the upper field. It is predicted that nitrogen doped C20H10N (bowl) with the maximum electron density adopts this structure for electrophilic reactions.
DOI: 10.15372/JSC20170123 |
