A Radical Anion Salt of 2,5‐Dimethyl‐N,N′‐dicyanoquinonediimine with Extremely High Electrical Conductivity

Abstract

Metallic conductivity that increases continuously up to 1.3 K and achieves values of over 500000 S cm−1 is exhibited by single crystals of the radical‐anion salt depicted here, which was prepared by electrocrystallization. The multidimensional electronic conductivity is discussed on the basis of the crystal structure. The CuI ions are arranged in chains, each of which is surrounded by four stacks of dicyanoquinonediimine radical anions (one negative charge per “dimer”).

Development of a Control Method for Conduction and Magnetism in Molecular Crystals

“…Firstly, an example is given here to illustrate the structural and electrical properties of molecular CT complexes. Such molecules as DM and DX in Figure 1, generally called R 1 ,R 2 -DCNQI, 34,35 form CT complexes with various kinds of metals to yield fine needle crystals M(R 1 ,R 2 -DCNQI) 2 (M = Li, Na, K, Ag, Cu, NH 4 , etc. ; Figure 2).…”

Structure of 1,4-benzenedicyanamide dianion derivatives

“…Charge-transfer complexes with the stoichiometry Cu(DCNQI)2, that incorporate the radical anion DCNQI, have been shown to possess metallic properties and in one instance conductivity increased with decreasing temperature reaching a maximum of 5 x 105Sm -1 at 3.5K (Aumuller, Erk, Klebe, Hunig, Von Schutz & Werner, 1986). These properties are largely the result of the planarity of the radical anion DCNQI molecule and its ability to form ¢r stacks in the solid state (Kato, Kobayashi & Kobayashi, 1989).…”

A High‐Conductivity Crystal Containing a Copper(I) Coordination Polymer Bridged by the Organic Acceptor TANC

“…This behavior is due to the interaction between the localized 3d-electron bands of the Cu ions and the p-electron conductive bands of DCNQI.[2] Therefore, the appropriate combination of donors and acceptors as molecular building blocks, which often form an electron-conducting solid, plays an important role in determining the electron-transport character of a molecular crystal.Molecules that form high-conductivity molecular solids, particularly organic acceptors, have been limited thus far to cyanoquinoid derivatives such as TCNQ [3] and DCNQI [4] and the metal complex [M(dmit) 2 ] (dmit = 1,3-dithiole-2-thioxo-4,5-dithiolato).[5] Molecular conductors with various electrondonor frameworks based on heterocyclic structures containing a chalcogen atom such as tetrathiafulvalene (TTF) [6] and tetramethyltetraselenofulvalene (TMTSF) [7] have also been realized, and studies are underway to discover a fundamental molecule with a stable electron-accepting framework to form molecular conductors with a desired transport behavior. Herein, we report a modifiable electron acceptor with 5,6,11,12-tetraazanaphthacene (TANC) as a new fundamental framework and the preparation of a high-conductivity crystal (1) from Cu I -TANC coordination polymers.…”

“…The high-conductivity crystal 1, which has the composition [{Cu(TANC)}F 0.5 ] n , was obtained from the reaction between TANC and [Cu(MeCN) 4 ]BF 4 in MeOH/MeCN in the form of thin, plate-like, indigo-blue crystals. The presence of half an equivalent of nonstoichiometric F À ions was determined by X-ray photoelectron spectroscopy (XPS) measurements and quantitative chemical analysis for F À ions.…”