DFT study of zigzag (n, 0) single-walled carbon nanotubes: C-13 NMR chemical shifts

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F16%3A00462577" target="_blank" >RIV/61388963:_____/16:00462577 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.jmgm.2016.04.008" target="_blank" >http://dx.doi.org/10.1016/j.jmgm.2016.04.008</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jmgm.2016.04.008" target="_blank" >10.1016/j.jmgm.2016.04.008</a>

Jazyk výsledku

angličtina

Název v původním jazyce

DFT study of zigzag (n, 0) single-walled carbon nanotubes: C-13 NMR chemical shifts

Popis výsledku v původním jazyce

C-13 NMR chemical shifts of selected finite-size models of pristine zigzag single walled carbon nanotubes (SWCNTs) with a diameter of similar to 0.4-0.8 nm and length up to 2.2 nm were studied theoretically. Results for finite SWCNTs models containing 1, 4 and 10 adjacent bamboo-type units were compared with data obtained for infinite tubes in order to estimate the reliability of small finite models in predicting magnetic properties of real-size nanotubes and to assess their tube-length dependence. SWCNTs were fully optimized using unrestricted density functional theory (DFT-UB3LYP/6-31G*). Cyclacenes, as the shortest models of open-ended zigzag SWCNTs, with systematically varying diameter were calculated as well. GIAO NMR calculations on the SWCNT and cyclacene models were performed using the BH and H density functional combined with relatively small STO-3G(mag) basis set, developed by Leszczyriski and coworkers for accurate description of magnetic properties. Regular changes of carbon C-13 chemical shifts along the tube axis of real size (6, 0) and (9, 0) zigzag carbon nanotubes were shown. The C-13 NMR shifts according to increasing diameter calculated for zigzag (n, 0, n=5-10) cyclacenes followed the trends observed for zigzag (n, 0) SWCNTs. The results for 4-units long SWCNTs match reasonably well with the data obtained for infinite zigzag (n, 0) SWCNTs, especially to those with bigger diameter (n = 8-15). The presence of rim hydrogens obviously affects theoretical C-13 chemical shieldings and shifts in cyclacenes and thus cyclacenes can provide only approximate estimation of C-13 NMR parameters of real-size SWCNTs. The NMR properties predicted for the longest 10-units long models of SWCNTs reliably correspond to results obtained for infinite nanotubes. They were thus able to accurately predict also recently reported experimental chemical shift of chiral (6, 5) SWCNT.

Název v anglickém jazyce

DFT study of zigzag (n, 0) single-walled carbon nanotubes: C-13 NMR chemical shifts

Popis výsledku anglicky

C-13 NMR chemical shifts of selected finite-size models of pristine zigzag single walled carbon nanotubes (SWCNTs) with a diameter of similar to 0.4-0.8 nm and length up to 2.2 nm were studied theoretically. Results for finite SWCNTs models containing 1, 4 and 10 adjacent bamboo-type units were compared with data obtained for infinite tubes in order to estimate the reliability of small finite models in predicting magnetic properties of real-size nanotubes and to assess their tube-length dependence. SWCNTs were fully optimized using unrestricted density functional theory (DFT-UB3LYP/6-31G*). Cyclacenes, as the shortest models of open-ended zigzag SWCNTs, with systematically varying diameter were calculated as well. GIAO NMR calculations on the SWCNT and cyclacene models were performed using the BH and H density functional combined with relatively small STO-3G(mag) basis set, developed by Leszczyriski and coworkers for accurate description of magnetic properties. Regular changes of carbon C-13 chemical shifts along the tube axis of real size (6, 0) and (9, 0) zigzag carbon nanotubes were shown. The C-13 NMR shifts according to increasing diameter calculated for zigzag (n, 0, n=5-10) cyclacenes followed the trends observed for zigzag (n, 0) SWCNTs. The results for 4-units long SWCNTs match reasonably well with the data obtained for infinite zigzag (n, 0) SWCNTs, especially to those with bigger diameter (n = 8-15). The presence of rim hydrogens obviously affects theoretical C-13 chemical shieldings and shifts in cyclacenes and thus cyclacenes can provide only approximate estimation of C-13 NMR parameters of real-size SWCNTs. The NMR properties predicted for the longest 10-units long models of SWCNTs reliably correspond to results obtained for infinite nanotubes. They were thus able to accurately predict also recently reported experimental chemical shift of chiral (6, 5) SWCNT.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CF - Fyzikální chemie a teoretická chemie

OECD FORD obor

—

Projekt

<a href="/cs/project/GA14-03564S" target="_blank" >GA14-03564S: Nové endohedrální aktinoidové fullereny a jejich vlastnosti. Od spektroskopie k molekulárním zařízením.</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Molecular Graphics & Modelling

ISSN

1093-3263

e-ISSN

—

Svazek periodika

67

Číslo periodika v rámci svazku

Jun

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

6

Strana od-do

14-19

Kód UT WoS článku

000379632200002

EID výsledku v databázi Scopus

2-s2.0-84973360966