Spin-dependent polarization effects of decoration of multi-walled carbon nanotubes by complexes of dithienylepyrrole derivatives with octahedral iron and lanthanides

H.V. Grushevskaya

Faculty of Physics Belarusian State University Minsk, 220030 BELARUS


Coordination mechanism for formation of organometallic compounds of such lanthanides (Ln) as Ce, Sm, Er and/or octahedral iron with dithienylepyrrole molecules (DTP) bonded with alkyl fragments has been established and studied. As provided by the compressibility analysis and the data of Raman, Mössbauer and NMR-spectroscopy, a valence state of iron in LB-monolayers tends to a high-spin state, and the organometallic compound is a complex of octahedral Fe (II) [1-3]. Since the transfer of an electron into conduction band changes the electronic configuration from 3d$^6$ to 3d$^5$, then the valence of iron is increased by one from Fe$^{2+}$ to Fe$^{3+}. Therefore, such coordination systems are called systems with mixed valence [4, 5]. An existence of the resonance between localized f-electron states and delocalized s(p)-electrons in the conduction band is known for inorganic compounds of rare-earth metals (Ln) [6]. In contrast to transition metal compounds with mixed valence, a mean or “fractional” valence of rare earth compounds is observed in experiments, and it is named as intermediate valence. It has been shown that the supramolecular compounds of dithienylepyrrole-pyrrole ligands with metal centers in intermediate valence states are formed. Complexes of dithienylepyrrole with octahedral iron and lanthanides have been deposited on multi-walled carbon nanotubes (MWCNTs) with the Langmuir - Blodgett technology. It has been established that such a decoration of carbon nanotubes by lanthanides and iron leads to spin-dependent dielectric polarization and does not degrade the electrophysical properties of MWCNTs. References [1] H. V. Grushevskaya, I. V. Lipnevich, T. I. Orekhovskaya. Coordination Interaction between Rare Earth and/or Transition Metal Centers and Thiophene Series Oligomer Derivatives in Ultrathin Langmuir-Blodgett Films, J. Mod. Phys. Vol. 4, 7-17 (2013). [2] H. V. Grushevskaya, N. G. Krylova, I. V. Lipnevich. Enhancement of Raman light scattering in dye-labeled cell membrane on metal-containing conducting polymer film, Int. J. Mod. Phys. B. Vol. 30, 1642018 (2016). [3] H V Grushevskaya, N G Krylova, I V Lipnevich. Design and compressibility of Langmuir monolayers from organometallic nanocyclic complexes, J. Phys. CS. Vol. 741, 012116 (2016). [4] J. Steed and J. Atwood, “Supramolecular Chemistry,” John Wiley & Sons, New York, Singapore City, 2000. [5] M. Alfimov, “Photonics of Supermolecular Nanosize Structures,” Izv. RAN, Ser. Chem., 2004, p. 1303. [6] D. Khomski, Uspekhi Phys. Nauk. Vol. 129, 443-485 (1979).