title: DFT calculations of structures, (13)C NMR chemical shifts, and Raman RBM mode of simple models of small-diameter zigzag (4,0) carboxylated single-walled carbon nanotubes.
abstract: Linearly conjugated benzene rings (acenes), belt-shaped molecules (cyclic acenes), and models of single-walled carbon nanotubes (SWCNTs) with one carboxylic group at the open end were fully optimized at the B3LYP/6-31G* level of theory. These models were selected to obtain some insight into the nuclear isotropic changes resulting from systematically increasing the basic building units of open-tip-monocarboxylated SWCNTs. In addition, the position of radial breathing mode (RBM), empirically correlated with the SWCNT diameter, was directly related with the radius of model cyclic acene rings. A regular convergence of selected structural, NMR, and Raman parameters with the molecular system size increase was observed, and a simple two-parameter mathematical formula enabled their estimation in infinity. The predicted (13) C NMR chemical shifts of carbon atoms close to the substituted rim of carboxylated models of zigzag (4,0) SWCNTs differed significantly from the pristine nanotubes.
authors.affiliation: Faculty of Chemistry, University of Opole, 48, Oleska Street, 45-052, Opole, Poland.
authors.forename: Teobald
authors.initials: T
authors.lastname: Kupka
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Chełmecka
authors.forename: Karol
authors.initials: K
authors.lastname: Pasterny
authors.forename: Michał
authors.initials: M
authors.lastname: Stachów
authors.forename: Leszek
authors.initials: L
authors.lastname: Stobiński