2 research outputs found
Noncovalent Interaction of Methylene Blue with Carbon Nanotubes: Theoretical and Mass Spectrometry Characterization
Noncovalent interaction of methylene blue dye cation
(MB<sup>+</sup>) with single walled carbon nanotubes (CNT) is characterized
by molecular
dynamics (MD) simulation, quantum chemical calculations, and laser
desorption/ionization (LDI) mass spectrometry. The MD simulation of
the (MB<sup>+</sup>)<sub><i>n</i></sub>–CNT (<i>n</i> = 1–10) complexes in water demonstrates that the
MB<sup>+</sup> cations are adsorbed on the nanotube surface in the
monomeric form. MD reveals both parallel and perpendicular orientations
of the MB<sup>+</sup> tricyclic plane in relation to the long axis
of CNT when placed in the water environment. The interaction energy
between the components of the complex in the perpendicular conformation,
as determined by quantum chemical calculations at the DFT/M05-2X/6-31++GÂ(d,p)
level of theory, explains why the bending of the MB<sup>+</sup> cation
at the sulfur atom weakens the π-system of bonds and allows
for the perpendicular orientation to occur. It is also found that
the adsorbed MB<sup>+</sup> induces positive electrostatic potential
around the adjacent semicylindrical segment of the nanotube. The mainly
monomolecular adsorption of the MB<sup>+</sup> cations at the CNT
surface leads to the absence in the LDI mass spectra of (MB<sup>+</sup>)<sub><i>n</i></sub>–CNT of features corresponding
to products of the reduction of MB<sup>+</sup> commonly observed in
the LDI mass spectra of crystalline dyes
Noncovalent Interaction of Methylene Blue with Carbon Nanotubes: Theoretical and Mass Spectrometry Characterization
Noncovalent interaction of methylene blue dye cation
(MB<sup>+</sup>) with single walled carbon nanotubes (CNT) is characterized
by molecular
dynamics (MD) simulation, quantum chemical calculations, and laser
desorption/ionization (LDI) mass spectrometry. The MD simulation of
the (MB<sup>+</sup>)<sub><i>n</i></sub>–CNT (<i>n</i> = 1–10) complexes in water demonstrates that the
MB<sup>+</sup> cations are adsorbed on the nanotube surface in the
monomeric form. MD reveals both parallel and perpendicular orientations
of the MB<sup>+</sup> tricyclic plane in relation to the long axis
of CNT when placed in the water environment. The interaction energy
between the components of the complex in the perpendicular conformation,
as determined by quantum chemical calculations at the DFT/M05-2X/6-31++GÂ(d,p)
level of theory, explains why the bending of the MB<sup>+</sup> cation
at the sulfur atom weakens the π-system of bonds and allows
for the perpendicular orientation to occur. It is also found that
the adsorbed MB<sup>+</sup> induces positive electrostatic potential
around the adjacent semicylindrical segment of the nanotube. The mainly
monomolecular adsorption of the MB<sup>+</sup> cations at the CNT
surface leads to the absence in the LDI mass spectra of (MB<sup>+</sup>)<sub><i>n</i></sub>–CNT of features corresponding
to products of the reduction of MB<sup>+</sup> commonly observed in
the LDI mass spectra of crystalline dyes