Geometric and Electronic Structures of Carbon Nanotubes Adsorbed with Flavin Adenine Dinucleotide:  A Theoretical Study

Abstract

As an attempt to study large systems involving weak interactions, we simulated the adsorption procedure of the coenzyme flavin adenine dinucleotide (FAD) interacting with semiconducting (10,0) and metallic (5,5) carbon nanotubes (CNTs) using a density functional tight binding method with the inclusion of an empirical dispersion term in total energy. It was found that the flavin and adenine groups of FAD could be attached to the CNT surface through π−π stacking but remain at the physisorption distance. The analysis of density of states shows that when interacting with the (10,0) CNT the FAD contributes more components in the band structure at the Fermi energy level, responsible for the enhancement of the semiconducting CNT electronic mobility.

Theoretical Studies on Formation, Property Tuning and Adsorption of Graphene Segments

“…Similar finding of band gap reduction has been found in the (7,3) polyC−DNA complex compared to the free semiconducing (7,3) tube (Enyashin and et al 2007). The finding of the new DOS formed between the (8,0) CNT conduction and valence bands is quite similar to our previous study of FAD/(10,0) CNT (Lin, Zhang et al 2007). This implies that the non-covalent modification (Fan, Zeng et al 2009).…”

“…In the FAD/(10,0) system, the FAD flavin group contributed more components in the band structure at the Fermi energy level (see Fig 11), which was responsible for the enhancement of the electronic transferability as observed in a cyclic voltammogram experiment (Guiseppi-Elie, Lei et al 2002). (Lin, Zhang et al 2007). …”

“…The role of π-π interactions in benzene dimers (Feng, Lin et al 2010) and in the stacking of graphene sheets (or graphene multilayers) have been thoroughly addressed in our detailed theoretical studies ). In our investigations (Lin, Zhang et al 2007;Fan, Zeng et al 2009), the weak van der Waal's (vdW) interactions were also found to be of pivotal significance in binding bio-molecules to carbon nanotubes (CNTs) from the viewpoints of important biological applications and bio-compatibility. These non-covalent, weak interactions do not affect the chemical and conductive properties of carbon nanotubes unlike covalent bonds and thereby aid an efficient retention of its pristine properties during their actual practical applications.…”

“…We simulated the adsorption procedure of the FAD on the semiconducting (10,0) and the metallic (5,5) carbon nanotubes (CNTs) using a density functional tight binding method with the inclusion of an empirical dispersion term in total energy. (Lin, Zhang et al 2007). …”

Interactions between free radicals and a graphene fragment: Physical versus chemical bonding, charge transfer, and deformation

“…To describe the van der Waals interaction between FRs and the graphene, we adopted the DFTB-D method, which uses an empirical dispersion term added into the DFTB total energy. [32,33] This method has been used successfully to study the interaction between organic molecules and materials, [34,35] the adsorption of water clusters on a graphene surface [36] and so forth.…”