Self-Assembly of Tetraazamacrocyclic Compounds on Single-Walled Carbon Nanotubes: Experimental and Theoretical Studies

摘要

To explore the possibility of reversible modification of carbon nanotube (CNT) sidewalls with aromatic ligands and their metal complexes employing aromatic stacking phenomena, we studied (experimentally and theoretically) interaction of a series of tetraazamacrocyclic compounds tetraazaannulene, meso-tetraphenylporphine, Ni(Ⅱ) and Cu(Ⅱ) complexes of tetramethyltetraazaannulene with single-walled carbon nanotubes. All of them are conjugated systems with a high degree of aromaticity. Molecular mechanics modeling was used to estimate what kind of arrangements can form. In some cases HRTEM results were obtained consistent with theoretical results. Adsorption of aromatic molecules, having a bent shape and/or hydrophobic substituents, allows to reversibly attach modifying chemical species. The latter stick strongly to the nanotube walls due to π-π and hydtophobic interactions and remain stable in aqueous solutions, but can be removed by washing with non-polar solvents.