Wires molecular

The basic properties of a molecular wire are that it should connect to two components (generally an electron acceptor and an electron donor) and conduct an electrical signal or impulse between 

An alternative approach to molecular conductors has been pioneered by Marye Fox of the University of Texas, USA, using block copolymers comprising electron donor and acceptor units, separated 

Interestingly, related polypeptide-based materials display differential electron-transfer rates depending on the orientation of the dipole of the peptide helix. This suggests that electron transfer in such systems may be controllable by externally applied potentials. Such results represent the beginning of the kind of long-range control and electron-transfer characteristics necessary for functional nanoscale optoelectronic devices. 

This discussion is intended to give a brief insight into the field of molecular switches. There are many other examples, in biological systems as well [11]. But reversible molecular switching in the solid state, in single crystals or in the polycrystalline phase, remains problematic and frequently cannot be achieved. 

The ability to connect by means of wiring is an important precondition for the fabrication of networks of molecular-electronic elements. For this purpose, as well as for the connection to macroscopic devices, one requires connecting wires on a molecular scale. The search for suitable molecular conductors has up to now been more a goal for molecular physics than for solid-state physics. We refer in this connection to Sects. 21.5 and 22.4, as well as 22.5, in the textbook by Haken and Wolf[l]. 

The conduction of electrons through single molecules is however in all known cases not an Ohmic conductivity, but rather a tunneling process. Molecular wires facilitate an electron transport relative to the vacuum, but they differ from metallic wires in terms of the order of magnitude as well as the mechanism of the conductivity. 

In order to understand the conductivity of single molecules and to be able to use them as wires, one must deal with the problem of the contacts. There must be a mechanism for bringing the charges into the conducting molecule and an understanding of how they are transported along it We refer the reader in this connection to the corresponding sections in [1] as well as in [2] and [3]. A summary of relevant methods and results can be fotmd in [12]. 

In searching for molecular wires, one can also consider the highly-conducting crystals from the group of radical-ion salts, the so-called organic metals (cf. 

---

The probability matrix plays an important role in many processes in chemical physics. For chemical reactions, the probability of reaction is often limited by tunnelling tlnough a barrier, or by the fonnation of metastable states (resonances) in an intennediate well. Equivalently, the conductivity of a molecular wire is related to the probability of transmission of conduction electrons tlttough the junction region between the wire and the electrodes to which the wire is attached. 

Polymer and chain formation is another property of chalcogen-nitrogen compounds that distinguishes them from their oxygen analogues. In addition to the unique, superconducting poly(sulfur nitride) (SN) (1.24) (Section 14.2), a variety of poly(thiazyl) chains such as RS5N4R (1.25) (Section 14.3) have been characterized. Interest in these chains stems from their possible use as models for the behaviour of (SN) and as components in molecular materials, e.g., as molecular wires. 

Materials that are comprised of small fragments of (SN) with organic terminal groups, e.g., ArSsNaAr and ArS5N4Ar (Ar = aryl), are of potential interest as molecular wires in the development of nanoscale technology. Consistent with simple band theory, the energy gap... 

The incorporation of S-N chains between metal centres by the use of heteroaryl substituents in complexes of the type 14.7 has been proposed as a way to generate new materials that may function as molecular wires. However, the synthesis of thiazyl chains bearing metal-binding sites has yet to be achieved. 

Fleterocycles as chemosensors in molecular wire approach to sensory signal amplification 98ACR201. 

Molecular Wires Oligomers and Polymers with the Poly(triacetylene) (PTA) Backbone... 

Many other opportunities exist due to the enormous flexibility of the preparative method, and the ability to incorporate many different species. Very recently, a great deal of work has been published concerning methods of producing these materials with specific physical forms, such as spheres, discs and fibres. Such possibilities will pave the way to new application areas such as molecular wires, where the silica fibre acts as an insulator, and the inside of the pore is filled with a metal or indeed a conducting polymer, such that nanoscale wires and electronic devices can be fabricated. Initial work on the production of highly porous electrodes has already been successfully carried out, and the extension to uni-directional bundles of wires will no doubt soon follow. 

In addition, SWNTs have been expected to act as acceptors or molecular wires in molecular photoelectric conversion since they have attractive electron-accepting... 

Grozema FC, Siebbeles LDA, Gelinck GH, Warman JM (2005) The Opto-Electronic Properties of Isolated Phenylenevinylene Molecular Wires. 257 135-164 Guiseppi-Elie A, Lingerfelt L (2005) Impedimetric Detection of DNA Hybridization Towards Near-Patient DNA Diagnostics. 260 161-186 Guo Y, see Coleman AW (2007) 277 31-88... 

So, to summarize, the hole transfer rate between Py and Ptz was determined using the transient absorption measurements of Py + and Ptz +, and we have shown that the hole transfer rate from Py + to Ptz depends on the distance and sequence between Ptz and Py. In other words, the hole transfer rate in DNA is modulated by designing the sequence of DNA and conjugated molecules. It is suggested that DNA may be utilized as a molecular wire by introducing several organic molecules at the appropriate site in DNA. 

Linear multinuclear metal complexes are attracting attention in the context of molecular electronics due to their projected use as molecular wires. 01igo(pyridyl)amido ligands are efficient scaffolds for lining up several Ni11 ions like a string. The first structurally characterized trinickel complex of this type, [Ni3(dpa)4Cl2] (dpa = bis(2-pyridyl)amide), showed a nearly linear Ni3 unit with Ni—Ni distances of around 244 pm.209 Penta-, hepta-, and nonanuclear systems have... 

Joachim, C. Roth, S., Eds. Atomic and Molecular Wires Kluwer, Dordrecht, 1997. 

Slama-Schwok A, Blanchard-Desce M, and Lehn JM. 1992. Caroviologen molecular wires—Pulse-radiolysis of bis(pyridinium) polyenes. Journal of Physical Chemistry 96 10559-10565. 

Davis WB, Svec WA, Ratner MA et al (1998) Molecular-wire behavior in p-phenylenevi-nylene oligomers. Nature 396 60-63... 

The synthesis of technologically interesting ROMP materials using (233) includes the preparation of molecular wires,701 liquid-crystal polymers,702,703 chiral supports for catalysis,704 redox-active macromolecules,705 photochromic materials706 and embedded clusters of CdSe.707 Polymers... 

Heteroaryl groups are present in the 4-pyridyl-ethynyl compounds81,99,100 and their extended variants with C=C-C6H4-C=C-pyr-4 ligands.81,99 These compounds can be quaternized with Mel or coordinated to a metal complex at their terminal pyridyl functions to give species addressed as molecular rods or molecular wires.81,99 Similar reactions were carried out with 3-phenanthrolinyl-ethynyl complexes,62 and special examples are also known with R based on calixarenes.51... 

Polymeric (isocyanide)gold(i) aryls ( gold oligo-phenylene-ethynylene-isonitriles ) were tested as electrical conductors at metal-molecule-metal junctions (7r-conjugated molecular wires), but the preparation, structure, and properties of the materials were not fully disclosed (Scheme 52).218... 

---