Noncovalent interactions between organometallic metallocene complexes and single-walled carbon nanotubes

• Published in: The Journal of chemical physics 2006-10, Vol.125 (15), p.154704-154704-12
• Main Authors: Sceats, Emma L., Green, Jennifer C.
• Format: Article
• Language: English
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.2349478

First principles density functional pseudopotential calculations have been used to investigate the nature of interactions between single-walled carbon nanotubes (SWNTs) and intercalated transition metal metallocene complexes, M ( η - C 5 H 5 ) 2 ( M Cp 2 ) . Three composites, M Cp 2 -graphene ( d t = ∞ ) , M Cp 2 @ ( 17 , 0 ) ( d t = 1.33 nm ) , and M Cp 2 @ ( 12 , 0 ) ( d t = 0.94 nm ) (where M = Fe , Co ), have been studied to probe the influence of the nanotube diameter ( d t ) on the nature and magnitude of the interactions. Theoretical results presented here demonstrate that these M Cp 2 @ SWNT composites are stabilized by weak π -stacking and C H ⋯ π interactions, and in the case of the Co Cp 2 @ SWNT composites there is an additional electrostatic contribution as a result of charge transfer from Co Cp 2 to the nanotube. The extent of charge transfer ( M Cp 2 → SWNT ) can be rationalized in terms of the electronic structures of the two fragments, or more specifically, the relative positions of the metallocene highest occupied molecular orbital and the conduction band of the nanotube in the electronic structure of the composite.