An extensive vibrational assignment of TTF and TTF‐d4 is achieved, improving the previously reported one through the use of polarized infrared spectra of single crystals of the monoclinic form. Infrared spectra of the monoclinic and triclinic forms are compared and the different crystal field effects discussed. Powder Raman and infrared spectra of (TTF)Br1.0 and (TTF‐d4)Br1.0, Raman depolarization ratios and infrared spectra of (TTF)ClO4 and (TTF‐d4)ClO4 solutions are reported. The assignment of the ag, b1u, b2u, and b3u fundamental modes of (TTF)+ and (TTF‐d4)+ radicals allows the identification of most of the relevant frequency shifts following the ionization of the TTF structure. The possible use of the ionization shifts for the study of the electronic charge distribution in the conducting TTF systems is considered. The parallel investigation of the concentration effects on the visible and infrared absorption spectra of TTF+ in solution let us to identify anomalous infrared absorptions associated with ...

Vibrational spectroscopy of molecular constituents of one‐dimensional organic conductors. Tetrathiofulvalene (TTF), TTF+, and (TTF+)2 dimer

Quasi-one-dimensional conductors

This review describes the synthesis of 1,3- and 1,2-tetrachalcogenafulvalenes, the chemical transformation of substituents, reactions of the ring systems and the synthesis of polymers with 1,3-tetrathiafulvalene units in the backbone and in the side chain. For selected charge-transfer complexes of tetrachalcogenafulvalenes the relation between molecular structure and solid-state structure, respectively, and electric conductivity are discussed. Superconducting properties of some charge-transfer complexes with tetrachalcogenafulvalenes as donor are reported. Preparations of important starting compounds for the synthesis of tetrachalcogenafulvalenes (like 1,2- and 1,3-dithiole, 1,3-thiaselenole, and 1,3-diselenole derivatives) have been considered in this review. Selected properties (melting point, UV-VIS absorption data and oxidation potentials) of 1,2- and 1,3-tetrachalcogenafulvalenes are summarized in appropriate tables.

Synthesis, Reactions, and Selected Physico-Chemical Properties of 1,3-and 1,2-Tetrachalcogenafulvalenes

In the course of investigations of organic metals we have investigated the cation-radical series TMTTF2-X′ with X′ = BF4, ClO4, PF6, SCN and Br. On this isomorphous series a large range of physical properties have been studied: electrical conductivity, magnetic susceptibility, EPR, optical reflectivity and specific heat. In correlation with crystallographic results, which indicate the existence of TMTTF diads, the dominant interactions are analyzed. It results that the metallic behavior at high temperatures and the occurrence of a Peierls distorsion below 100 K arise mainly from a competition between electron-electron and electron-phonon coupling inside the cation-radical chains

Physical Properties of One Dimensional Conductors

Model for conduction in TCNQ salts

The solid state physical properties of an isomorphous series of TTF salts (TTF11 (SCN)6, TTF11 (SeCN)6, and TTF7I5) were examined. While there was no noticeable trend in the conductivity (as a function of temperature and anion), the effective Fermi energy (?F) and the magnetic susceptibility transition temperature exhibited a definite trend as a function of anion. There is a correlation between the above properties and subtle variations in solid state structure of each of the above salts.

A systematic study of an isomorphous series of organic solid state conductors based on tetrathiafulvalene

Preparation and some properties of tetramethyldithiadiselenafulvalene (TMDTDSF) are described. It forms the expected (donor)2 X salts. Properties of the PF−6 salt are described as well as properties of alloys of the title compound with tetramethyltetraselenafulvalene (TMTSF). (TMDTDSF)2PF6 is a relatively poor conductor even though it is isomorphous with the high‐pressure superconductor (TMTSF)2PF6. The profound difference in properties between these two solids is ascribed to disorder in the arrangement of sulfur and selenium atoms along the donor stacks in (TMDTDSF)2PF6. Alloying very small amounts of TMDTDSF into (TMTSF)2PF6 causes the metal‐to‐insulator transition temperature (TMI) to move up smoothly from 11 K for pure (TMTSF)2PF6 to ∼200 K for pure (TMDTDSF)2PF6 due to increasing disorder as TMDTDSF is incorporated.

F. J. DiSalvo

Papers

A systematic study of an isomorphous series of organic solid state conductors based on tetrathiafulvalene

Tetramethyldithiadiselenafulvalene (TMDTDSF): Properties of its hexafluorophosphate salt and alloys with tetramethyltetraselenafulvalene