(Invited) Distinct Coating Displacement Kinetics for Single-Wall Nanotube Enantiomers

Abstract

It is known that specific oligomers of single-stranded DNA (ssDNA) can show selectivity toward different (n,m) structural species of single-wall carbon nanotubes (SWCNTs). These selective interactions can also extend to the left- and right-handed helical forms of a single (n,m) species. An example of this is the ability of the (ATT)4 oligo to strongly distinguish between the two optical isomers of (7,5) SWCNTs. We show that this helicity-selective coating interaction causes a resolvable shift between the two enantiomers’ fluorescence spectra. Most strikingly, the room temperature rates of displacement of the (ATT)4 coating on exposure to sodium deoxycholate are found to differ by two orders of magnitude. This is shown from measurements of time dependent fluorescence spectra. During coating displacement, the enantiomer with high affinity for the ssDNA oligomer is deduced to form an intermediate hybrid that is not observed for the low affinity enantiomer. These results demonstrate the diverse and dramatic enantiomeric differences in properties of SWCNTs complexed with ssDNA.