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Three radical cation salts of BDH-TTP with the paramagnetic [ReF6]2- and diamagnetic [ReO4]- anions have been synthesized: K-(BDH-TTP)4ReF6 (1), κ-(BDH-TTP)4ReF6⋅4.8H2O (2) and pseudo-κ"-(BDH-TTP)3(ReO4)2 (3). The crystal and band structures, as well as the conducting properties of the salts, have been studied. The structures of the three salts are layered and characterized by alternating κ-(1, 2) and κ"-(3) type organic radical cation layers with inorganic anion sheets. Similar to other κ-salts, the conducting layers in the crystals of 1 and 2 are formed by BDH-TTP dimers. The partial population of positions of Re atoms and disorder in the anionic layers of 1-3 are their distinctive features. Compounds 1 and 2 show the metallic character of conductivity down to low temperatures, while 3 is a semiconductor. The ac susceptibility of crystals 1 was investigated in order to test the possible slow relaxation of magnetization associated with the [ReF6]2- anion. [ABSTRACT FROM AUTHOR]

The structure and properties of the radical cation salt based on [pi]-donor BETS (BETS = bis(ethylenedithio)tetraselenafulvalence) with tri(dicyanaamido)manganate(II) anion, [(BETS).sub.2]Mn[N(CN).sub.2]].sub.3] are reported. The crystal structure shows a transition into a superconducting state with [T.sub.c] = 5 K at P = 0.3 kbar and at ambient pressure the compound exhibits a metal-insulator transition at [T.sub.1] = 21 K and an AFM ordering at [T.sub.0] = 5 K.

Properties of the spin systems of the localized 3d Mn2+ ions and the conduction π electrons in quasi-two-dimensional organic conductor κ-(BETS)2Mn[N(CN)2]3 were accessed using ¹H and 13C NMR in order to find their relation to the metal-insulator transition which occurs at ~23K. The transition of the system into the insulating state is shown to be followed by localization of the π spins into a long-range ordered staggered structure of AF type. In contrast, the 3d Mn2+ electron spin moments form a disordered tilted structure, which may signify their trend to AF order, frustrated geometrically by the triangular arrangement of Mn in the anion layer. This result suggests that the MI transition in κ-(BETS)2Mn[N(CN)2]3 is not the consequence of the interactions within the Mn2+ spins but due to the interactions within the π-electron system itself. Vice versa, it is more likely that the disordered tilted structure of the Mn2+ spins is induced by the ordered π-spins via the π-d interaction. [ABSTRACT FROM AUTHOR]

The article reports on a study of the structure and properties of the radical cation salt based on pie-donor bis(ethylenedithio)tetraselenafulvalene with tri(dicyanamido)manganate anion. The compound is metallic and superconducting. It is necessary to conduct detailed studies in magnetic fields to clarify the nature of the low-temperature magnetic state and its influence on the conduction system.

The radical cation salt ET(NCS)0.77 [bis(ethylenedithio)tetrathiafulvalene thiocyanate (1/0.77)] has been prepared for the first time by electrocrystallization and its crystal and electronic structure at 110 K was investigated. The unit-cell dimensions are orthorhombic, a = 6.638 (1), b = 8.309 (2), c = 28.776 (6) A, V = 1587.1 (6) A3, space group Pbcm, Z = 4. The compound has a layered structure. The ET radical cations of the conducting cationic layer build stacks. In the anionic layer the thiocyanate groups form polymeric chains where they are oriented in a 'head-to-tail' mode. The structure has short intermolecular contacts of the cation-cation, anion-anion and cation-anion types, which leads to the formation of a three-dimensional structure of intermolecular interactions. This phenomenon is very rare in molecular conductors. Tight binding band structure calculations suggest, however, that the interlayer interactions through the anions are weak and that the incomplete occupation of the anion sites is the reason for the activated conductivity of the salt.