Two oligo‐(aryleneethynylene)s, with coplanarity of main chain and tetrathiafulvalene (TTF) side chains, have been prepared and characterized. The X‐ray diffractions (XRDs) show that their π‐extended coplanar backbones can form continuous π‐stacking. For the two oligomers, one stacks in the inter‐digitation packing mode; another stacks in the end‐to‐end packing mode. Cyclic voltammetries reveal that the two oligomers have almost the same reversible electroactive properties. The TTF units of the two oligomers can be oxidized to TTF . 1+ by Fe(bpy)3(PF6)3 (bpy = 2,2′‐bipyridine). The band gaps, deduced from UV‐Vis absorption spectra, are 1.92 and 2.03 eV, respectively. The conductivities of the two oligomers are 1 × 10?5 and 6 × 10?8 S · cm?1 at room temperature. The charge transfer (CT) complexes of the oligomers and tetracyanoquinodimethane (TCNQ) exhibit higher conductivity up to 0.2 S · cm?1.
The electrochemical behavior of eight bis(ethylenedithio)tetrathiafulvalene and three tetrathiafulvalene derivatives has been investigated to explore the influence of electron withdrawing and donating groups attached to the peripheral dithiin and thiophene rings. 相似文献
The metallic and semiconducting character of a large family of organic materials based on the electron donor molecule tetrathiafulvalene (TTF) is rooted in the partial oxidation (charge transfer or mixed valency) of TTF derivatives leading to partially filled molecular orbital-based electronic bands. The intrinsic structure of such complexes, with segregated donor and acceptor molecular chains or planes, leads to anisotropic electronic properties (quasi one-dimensional or two-dimensional) and morphology (needle-like or platelet-like crystals). Recently, such materials have been synthesized as nanoparticles by intentionally frustrating the intrinsic anisotropic growth. X-ray photoemission spectroscopy (XPS) has emerged as a valuable technique to characterize the transfer of charge due to its ability to discriminate the different chemical environments or electronic configurations manifested by chemical shifts of core level lines in high-resolution spectra. Since the photoemission process is inherently fast (well below the femtosecond time scale), dynamic processes can be efficiently explored. We determine here the fingerprint of partial oxidation on the photoemission lines of nanoparticles of selected TTF-based conductors. 相似文献