Molecular conductors as nanoparticles in the presence of long-chain alkyl imidazolium salts or amphiphilic molecules

Abstract

Nanoparticles of two molecule-based conductors namely, TTFTCNQ and TTF[Ni(dmit) 2 ] 2 , have been prepared in organic solution in the presence of ionic or non-ionic species bearing a long-chain alkyl group, acting as growth controlling agents. The size, morphology and state of dispersion of the nanoparticles depended on the nature of the growth-controlling agent and the reaction temperature. In the presence of a long-chain-alkyl-based ionic liquid at -50 °C, electron micrographs evidence that TTFTCNQ nano-objects are frequently elongated, whereas TTF[Ni(dmit) 2 ] 2 nanoparticles are aggregated. In the presence of a neutral long-chain-alkyl-based imine at room temperature, nanoparticles are spherical (mean diameter less than 20 nm) and well dispersed. Vibration spectra evidence that the amounts of charge transfer for TTFTCNQ and TTF[Ni(dmit) 2 ] 2 as nano-objects are very similar to those for the same phases as bulk materials. According to the thermoanalytical investigations, the prepared nanoparticles are stable thermally up to approximately 200 °C, their decomposition is generally a multi-step process. Their heat treatment results in various sulfur containing volatiles (CS 2 , SO 2 , H 2 S), moreover HCN is also detected in the case of nitrogen containing molecules (TCNQ).

Nanoparticles of tetrathiafulvalene chloride derivatives grown in the presence of amphiphilic molecules

“…lt is worth men tioning that the amphiphilic molecule N octylfurfurylimine, employed in those conditions, did not act as an efficient growth controlling agent as it did for the metallo organic based oonductor TI'F[Ni(dmithh [11). In this latter case, the use of the same amount of N octylfurfurylimine vs. TI'F allowed access to only spherical and well dispersed nano particles of TIF[Ni(dmithh, exhibiting a mean diameter of about 12nm [11). Samples prepared by using either lower or higher amount of N octylfurfurylimine, such as 1 or 10 M eq.…”