Swnt-Sorting with a Removable Solubilizer Based on Dynamic Supramolecular Coordination Chemistry

Tuesday, 26 May 2015: 09:00
Lake Huron (Hilton Chicago)
N. Nakashima (Dept Applied Chem. & WPI-I2CNER, Kyushu University, Department of Applied Chemistry, Kyushu University) and F. Toshimitsu (Kyushu University)
Highly pure semiconducting single-walled carbon nanotubes (SWNTs) are essential for the next generation of electronic devices, such as field-effect transistors and photovoltaic applications, but contamination by metallic-SWNTs reduces the efficiency of their associated devices. Polyfluorene-based copolymers (PFOs)1, 2 have been intensively studied because they dissolve/extract only sem-SWNTs in toluene by a simple sonication method. We have previously demonstrated a rational method for the selective extraction of a specific chirality of the sem-(n,m) SWNTs using a series of systematically designed fluorene-based copolymers3-4. Moreover, we revealed that the PFO copolymers with a bulky optically active moiety could separate the right- and left-handed sem-SWNTs5. However, there are several serious problems when using PFOs; that is, difficulty in the removal of the wrapped PFOs from the SWNTs/PFO composites6, 7 as well as their low extraction efficiency from the as-produced SWNTs1, 2.

     Here we report a simple and efficient method for the separation of semiconducting- and metallic-SWNTs based on supramolecular complex chemistry.8 We describe the synthesis of metal-coordination polymers (CP-M) composed of a fluorene-bridged bisphenanthroline ligand and metal ions. Based on a difference in the ‘solubility product’ of CP-M-solubilized semiconducting-SWNTs and metallic-SWNTs, we readily separated semiconducting-SWNTs. Furthermore, the CP-M polymers on the SWNTs were simply removed by adding a protic acid and inducing depolymerization to the monomer components. We also carried out molecular mechanics calculations to reveal the difference of binding and wrapping mode between CP-M/semiconducting-SWNTs and CP-M/metallic-SWNTs.

     This study opens a new stage for the use of such highly pure semiconducting-SWNTs in many possible applications.



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[3] Ozawa, H. et al. J. Am. Chem. Soc. 133, 2651–2657 (2011).

[4] Ozawa, H., Ide, N., Fujigaya, T., Niidome, Y., Nakashima, N. Chem. Lett. 40, 239–241 (2011).

[5] Akazaki, K., Toshimitsu, F., Ozawa, H., Fujigaya, T., Nakashima, N. J. Am. Chem. Soc. 134, 12700–12707 (2012).

[6]  Izard, N. et al., App. Phys. Lett. 92, 243112 (2008).

[7] Jakubka, F. et al., ACS Macro Lett. 1, 815–819 (2012).

[8] Toshimitsu, F., Nakashima, N. Nature Comm., 2014, 5, art no. 5041.