Quantum-chemical design of covalent linkages for interconnecting carbon nanotubes

The possibility of interconnecting carbon nanotubes (CNTs) through their ends using covalent linkages has been computationally explored. By employing density functional theory (DFT) calculations with Gaussian-type orbitais (GTOs) we have optimized the geometry of four CNT-based model junctions each containing five covalent linkages. The linkages investigated here are the disulfide (-S-S-) and peptide (-CONH-) linkages, which are commonly found in proteins, and the ethylenedioxy (-O-CH₂-CH₂-O-) and ethynyl (-C≡C-) linkages which can be synthesized in the chemistry laboratory. The geometric and electronic structures computed for these four models are thoroughly discussed.