Molecular superconductors organic

Keywords Cation-radical salts, Molecular conductors, Organic superconductors, Organometallic anions, Tetrakis(trifluoromethyl)metallates, Tetrathiafulvalene... 

Since the discovery of the first organic semiconductor perylene-bromine complex in 1954 [1], a large number of molecular conductors, including more than 100 molecular superconductors, have been prepared. Conducting molecular materials are characterized by the following features ... 

Saito G, Yoshida Y (2007) Development of conductive organic molecular assemblies organic metals, superconductors, and exotic functional materials. Bull Chem Soc Jpn 80 1-137... 

The first edition of this textbook was widely praised. In this new edition the authors have taken the opportunity to bring the work completely up to date by the addition of new material on mesoporous materials, fullerenes, molecular magnets, organic conductors and high-temperature superconductors. All of the chapters have been revised with new additional sections. 

Supermolecular Siruclures Speculative work aimed at superconductors, organic metals. 3D memory storage, molecular switches. 

The optical properties of conducting polymers are important to the development of an understanding of the basic electronic structure of the material. These and other problems were described in various books and review papers [90-93]. Raman spectroscopy is also an ideal tool for predicting many important electronic properties of molecular materials, organic conductors, and superconductors as well as for understanding their different physical properties, since it is a nondestructive tool, which can be used in situ and with spatial resolution as good as 1 xm. 

Figure 1 Prototype molecules TTF (tetrathiafulvalene and TMTSF (tetramethyl-tetraselenafulvalene) which are used for the elaboration of organic conductors TTF-TCNQ or superconductors (TMTSF)2X. View of the crystal structure of some molecular superconductors (a) (TMTSF)2PF6 (b) (alkali)3 C (c) (BEDT-TTF)2Cu(SCN)2 side view (d) view along the axis perpendicular to the conducting plane.

The preparation of superconductor/organic conduc-tor/superconductor structures suitable for supercurrent measurements is important for the continued growth of this new area of research. Toward this objective, methods have been developed for the controlled growth of conductive polymer and vapor-phase deposition of (BEDT-TTF Ia systems. Molecular engineering of high-7c structures and devices made possible with the newly discovered high-7c self-assembly procedure will aid in the further development of these studies. 

All metals conduct electricity on account of the mobility of the electrons that bind the atoms together. Ionic, molecular, and network solids are typically electrical insulators or semiconductors (see Sections 3.f3 and 3.14), but there are notable exceptions, such as high-temperature superconductors, which are ionic or ceramic solids (see Box 5.2), and there is currently considerable interest in the electrical conductivity ol some organic polymers (see Box 19.1). 

Cowan DO, Fortkort JA, Metzger RM (1991) Design constraints for organic metals and superconductors. In Metzger RM, Day P, Papavassiliou GC (eds) Lower-dimensional systems and molecular electronics. NATO ASI Ser, vol B248. Plenum Press, New York,... 

Table 1.8. Material, P and of selected molecular organic superconductors classified according to the point group of the donor...

The neutral insulator TMTSF, which shows field-effect conduction with /Th — 0.2 cm s (Nam et al, 2003), when transformed into a Bechgaard salt also becomes superconducting, but at lower temperatures. In this case the perfect segregation of organic and inorganic molecular planes leads to confined electronic systems, which in the normal state are quasi ID. Organic superconductors based on the BEDT-TTF molecule represent the case of pure 2D electronic systems. 

In this edition, we have incorporated new material in all the chapters and updated references to the literature. New sections dealing with porous solids, fullerenes and related materials, metal nitrides, metal tellurides, molecular magnets and other organic materials have been added. Under preparative strategies, we have included new types of synthesis reported in the literature, specially those based on soft chemistry routes. We have a new section covering typical results from empirical theory and electron spectroscopy. There is a major section dealing with high-temperature oxide superconductors. We hope that this edition of the book will prove to be a useful text and reference work for all those interested in solid state chemistry and materials science. 

The prospective applications ofmolecular assemblies seem so wide that their limits are difficult to set. The sizes of electronic devices in the computer industry are close to their lower limits. One simply cannot fit many more electronic elements into a cell since the walls between the elements in the cell would become too thin to insulate them effectively. Thus further miniaturization of today s devices will soon be virtually impossible. Therefore, another approach from bottom up was proposed. It consists in the creation of electronic devices of the size of a single molecule or of a well-defined molecular aggregate. This is an enormous technological task and only the first steps in this direction have been taken. In the future, organic compounds and supramolecular complexes will serve as conductors, as well as semi- and superconductors, since they can be easily obtained with sufficient, controllable purity and their properties can be fine tuned by minor adjustments of their structures. For instance, the charge-transfer complex of tetrathiafulvalene 21 with tetramethylquinodimethane 22 exhibits room- temperature conductivity [30] close to that of metals. Therefore it could be called an organic metal. Several systems which could serve as molecular devices have been proposed. One example of such a system which can also act as a sensor consists of a basic solution of phenolophthalein dye 10b with P-cyciodextrin 11. The purple solution of the dye not only loses its colour upon the complexation but the colour comes back when the solution is heated [31]. 

D. Gatteschiin Organic Conductors, Superconductors and Magnets From Synthesis to Molecular Electronics, L. Ouahab and E. Yagubskii, eds. NATO Science Series n, Vol. 139, Kluwer, Dordrecht, Holland, 2004, pp. 179-196. 

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