Organic Superconducting Solids

Recently two more detailed but different procedures for synthesizing deuterated and hydrogenated TMTSF have become available. Certain steps in these procedures are difficult to perform and give low yields. Therefore, we have developed a synthesis that combines and elaborates on the two procedures and is easily performed with good yields. 

The following common laboratory solvents are distilled before use as follows chloroform (over alumina), diethyl ether (over FeS04), dichloromethane, benzene, heptane, and 1,1,2-trichloroethane. Methanol and ethyl acetate are used as obtained. Distilled water and aqua regia are used as described herein. It should be noted that lV-(dichloromethylene)-lV-methyl methanaminium chloride (phosgene iminium chloride) [Aldrich Chemical], trimethyl phosphite [Strem Chemicals] and hydrogen selenide [Scientific Gas Products] are all air- and/or moisture-sensitive and can be used only in a dry, inert atmosphere. 

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Saito, G. (1997). Organic superconducting solids. In Organic molecular solids. Properties and applications (ed. W. Jones), pp. 309 0. CRC Press, Boca Raton, FL. [191]... 

Schweitzer, D., Gartner, S., Grimm, H., Gogu, E., and Keller, H. J., Superconductivity in polycrystalUne pressed samples of organic metals. Solid State Commun., 69, 843, 1989. 

The first chemical transformations carried out with Cjq were reductions. After the pronounced electrophilicity of the fullerenes was recognized, electron transfer reactions with electropositive metals, organometallic compounds, strong organic donor molecules as well as electrochemical and photochemical reductions have been used to prepare fulleride salts respectively fulleride anions. Functionalized fulleride anions and salts have been mostly prepared by reactions with carbanions or by removing the proton from hydrofullerenes. Some of these systems, either functionalized or derived from pristine Cjq, exhibit extraordinary solid-state properties such as superconductivity and molecular ferromagnetism. Fullerides are promising candidates for nonlinear optical materials and may be used for enhanced photoluminescence material. 

As mentioned before, we shall use small molecules to introduce the fundamentals for more complex molecules, the real core of this book, which will be listed in the next section. Such molecules form solids with remarkable properties (metallicity, superconductivity, ferromagnetism, etc.), some of them at ambient conditions or at much lower hydrostatic pressures than those found for H2 and N2, and some technological applications have been already developed, deserving the name of functional materials. Most of the molecules studied in this book are planar, or nearly planar, which means that the synthesized materials reveal a strong 2D structural character, although the physical properties can be strongly ID, and because of this 2D distribution we shall study surfaces and interfaces in detail. In particular, interfaces play a crucial role in the intrinsic properties of crystalline molecular organic materials and Chapter 4 is devoted to them. 

Following ic-(ET)2Cu2(CN)3, five materials [364], including EtMe3Sb[Pd (dmit)2]2 as an organic solid [365], have been found to have quantum spin liquid states however, superconductivity has been confirmed only for k-(ET)2Cu2(CN)3. 

Sakata J, Sato H, Miyazaki A, Enoki T, Okano Y, Kato R (1998) Superconductivity in new organic conductor K-(BEDSe-TTE)2CuN(CN)2Br. Solid State Commun 108 377-381... 

Organic solids have received much attention in the last 10 to 15 years especially because of possible technological applications. Typically important aspects of these solids are superconductivity (of quasi one-dimensional materials), photoconducting properties in relation to commercial photocopying processes and photochemical transformations in the solid state. In organic solids formed by nonpolar molecules, cohesion in the solid state is mainly due to van der Waals forces. Because of the relatively weak nature of the cohesive forces, organic crystals as a class are soft and low melting. Nonpolar aliphatic hydrocarbons tend to crystallize in approximately close-packed structures because of the nondirectional character of van der Waals forces. Methane above 22 K, for example, crystallizes in a cubic close-packed structure where the molecules exhibit considerable rotation. The intermolecular C—C distance is 4.1 A, similar to the van der Waals bonds present in krypton (3.82 A) and xenon (4.0 A). Such close-packed structures are not found in molecular crystals of polar molecules. 

The solid-state and organic chemistries of fullerenes are currently active areas of research with possible applications, for instance, in the field of superconductivity ( . As illustrated in Fig. 1, more than 3000 papers now have appeared in refereed journals (2). Several excellent reviews summarizing physical (3), solid-state (4), and organic chemis-... 

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