Accession Number : ADA322702

Title :   Organic and Polymeric Superconductors,

Descriptive Note : Final rept. 30 Sep 92-29 Mar 96,

Corporate Author : ALABAMA UNIV UNIVERSITY DEPT OF CHEMISTRY

Personal Author(s) : Metzger, Robert M.

PDF Url : ADA322702

Report Date : 12 FEB 1997

Pagination or Media Count : 8

Abstract : The synthetic chemistry of dithiadiazafulvalenes (DTDAF) was studied in detail: these one and two-electron donors, ore powerful than the well-known tetrathiafulvalenes (TTF, 1), but more chemically more tractable than the unstable tetraazafulvalenes, are a significant departure from ordinary organic donors, and therefore show promise in the search for new organic superconductors. A 2:5 complex of diphenyldiacetyldithiadiazafulvalene (o2Ac2DTDAF, 4c) with the electron acceptor tetracyanoquinodimethan (TCNQ, 11a), including one molecule of acetonitrile, the solvent of crystallization (CH3CN), provided room-temperature conductivity o=0.011 S/cm (Siemens per centimeter). An unusual diamagnetic flux exclusion signal (for 5 per cent of the sample at 4.4 Kelvin) was determined to be an artifact due to a ferromagnetic impurity. A TCNQ complex of dimethyltetracety1DTDAF, 4b had o=0.083 S/cm at room temperature. A new acceptor, dioxotetracyanobisindanedione vinylidene (DOTCBIV), 5, provided a complex with TTF with o=0.6 S/cm at room temperature. Many complexes with fullerene, C60 (12), were made, but were electrically insulating. Studies of Langmuir-Blodgett films of potassium-doped C60 (monolayers on polyethylene terephthalate) may help to determine the boundary between 2-D and 3-D superconductivity.

Descriptors :   *POLYMERS, *SUPERCONDUCTORS, *ORGANIC MATERIALS, ACETONITRILE, LAYERS, MOLECULES, FLUX(RATE), SYNTHESIS(CHEMISTRY), CRYSTALLIZATION, FULLERENES, CARBON, IMPURITIES, ROOM TEMPERATURE, SOLVENTS, ELECTRON ACCEPTORS, ELECTRON TRANSITIONS, FERROMAGNETIC MATERIALS, DIOXIDES, DIAMAGNETISM, DONORS(MEDICINE), POLYETHYLENE TEREPHTHALATE.

Subject Categories : Organic Chemistry
      Polymer Chemistry
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE