The Magnetizability and Chemical Shift Relationship in Carbon Nanotubes with PNP or NPN Junction

Abstract

Total-atomic magnetizability obtained from Quantum theory of Atoms in Molecules (QTAIM) prepares viewpoint to the electronic current density summation in atomic basin and between adjacent atomic basins. The authors present a theoretical investigation of the relationship between the magnetizabilities and the 13 C NMR chemical shifts for (3 3)4 armchair, (4 3) chiral and (6 0)3 zigzag carbon nanotubes with dangling bonds. These structures are doped with B (boron) and N (nitrogen) at the end of the tube to form a bridge of the PNP or NPN junction. The value of atomic charges, the magnetizability, the 13 C NMR chemical shifts are obtained at the RHF and B3LYP method in conjunction with 3-21G and 6-31G basis sets. It is demonstrated that total-atomic magnetizability has a relatively linear relationship with 13 C chemical shift in (4 3) chiral and (6 0) 3 zigzag carbon nanotubes and their connected forms to the PNP junction or NPN junction, so the regression coefficients are more than 0.9 in the chiral and zigzag carbon nanotube models. But there is no such perfectly linear relationship in (3 3)4 armchair carbon nanotube and their connected forms to the PNP junction or NPN junction. Of course in all of models, the 13 C chemical shift increases in carbon nanotubes and their connected forms to PNP or NPN junction, when the total-atomic magnetizability is increasing.