Direct Measurement of Electron Transfer in Nanoscale Host–Guest Systems: Metallocenes in Carbon Nanotubes. Issue 38 (28th July 2016)

• Record Type: Journal Article
• Authors: McSweeney, Robert L.; Chamberlain, Thomas W.; Baldoni, Matteo; Lebedeva, Maria A.; Davies, E. Stephen; Besley, Elena; Khlobystov, Andrei N.
• Is Part Of: Chemistry. Volume 22:Issue 38(2016)
• Page Start: 13540
• Page End: 13549
• Publication Date: 2016-07-28
• Subjects: carbon nanotubes -- charge transfer -- electrochemistry -- host–guest systems -- metallocenes; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201602116
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Electron‐transfer processes play a significant role in host–guest interactions and determine physicochemical phenomena emerging at the nanoscale that can be harnessed in electronic or optical devices, as well as biochemical and catalytic systems. A novel method for qualifying and quantifying the electronic doping of single walled carbon nanotubes (SWNTs) using electrochemistry has been developed that establishes a direct link between these experimental measurements and ab initio DFT calculations. Metallocenes such as cobaltocene and methylated ferrocene derivatives were encapsulated inside SWNTs (1.4 nm diameter) and cyclic voltammetry (CV) was performed on the resultant host–guest systems. The electron transfer between the guest molecules and the host SWNTs is measured as a function of shift in the redox potential ( E 1/2 ) of Co II /Co I, Co III /Co II and Fe III /Fe II . Furthermore, the shift in E 1/2 is inversely proportional to the nanotube diameter. To quantify the amount of electron transfer from the guest molecules to the SWNTs, a novel method using coulometry was developed, allowing the mapping of the density of states and the Fermi level of the SWNTs. Correlated with theoretical calculations, coulometry provides an accurate indication of n/p‐doping of the SWNTs. Abstract : In a tube : Encapsulation of metallocenes inside single‐walled carbon nanotubes (SWNTs) gives rise to electronic doping of the SWNTs. The degree of electron transfer within these host–guest systems is quantified using coulometry, which, correlated with theoretical calculations, provides an accurate indication of n/p‐doping of the SWNTs.