Coordination chemistry on the surface of single-walled carbon nanotubes

A facile method to coordinate transition metal complexes (TMCs) on single-walled carbon nanotubes (SWNTs) has been developed. Reaction of Zn(OAc)2 with carboxylic acid functionalized SWNTs (SWNT-COOH) affords SWNT complexes ‘zipped-together’ by zinc carboxylate units (termed SWNT-TMC-1 herein). Reactions of SWNT-TMC-1 with 2,2′-bipyridine or 4,4′-bipyridine gave two new SWNT-TMCs, the former being ‘unzipped’ (SWNT-TMC-2), and the latter involving an additional ligand bridge between the zinc ions (SWNT-TMC-3). Inclusion of 2,2′-bipyridine and 4,4′-bipyridine into the SWNT-TMCs was confirmed by IR spectroscopy. The microstructures of SWNT-TMC-2 and SWNT-TMC-3 were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (Xps), elemental mapping and linear profiles analysis.