Synthesis molecular wires

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. 

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... 

Ashwell GJ, Urasinska-Wojcik B, Phillips J (2010) In situ stepwise synthesis of functional multijunction molecular wires on gold electrodes and gold nanoparticles. Angew Chem Int Ed 49 3508-3512... 

R. E. Martin, T. Mader, F. Diederich, Monodisperse Poly(triacetylene) Rods Synthesis of a 11.9 nm Long Molecular Wire and Direct Determination of the Effective Conjugation Length by UV/Vis and Raman Spectroscopies , Angew. Chem Int. Ed. Engl. 1999,38, 817-821. 

The use of molecular wires and devices for electronics applications is destined to occur. The ability to control molecular structures at the subnanometer scale is obvious throughout chemical synthesis. These are the same techniques that have been optimized over the last 50 years for the synthesis and modification of compounds for pharmaceutical, dye, petroleum, and fine chemical indus-... 

After the discovery by Fischer and Maasbol of the first stable carbene complexes in 1964, i.e., [(CO)5W =C(OMe)R ] [21], generation of related metaUacumulene derivatives [M]=C(=C) =CR2 (n > 0) was obviously envisaged. Thus, it is presently well-established that stabilization of these neutral unsaturated carbenes by coordination to a transition metal center is possible by the use of the lone pair of electrons on the carbenic carbon atom, via formation of a metal-carbon a-bond (electron back-donation from the metal fragment to the carbon ligand may strengthen this bond). This has allowed the development of a rich chemistry of current intense interest due to the potential applications of the resulting metallacumulenic species in organic synthesis, as well as in the construction of molecular wires and other nanoelectronic devices [22]. 

The present chapter will not deal with general topics of liquid crystals or crown ethers as this exceeds the scope of this volume. Interesting reviews and monographs on liquid crystals and their properties can be found in the literature [10-13]. The synthesis of crown ethers can be challenging. Most commonly, the synthetic routes are based on procedures established by Pedersen [14-17]. A review by Bradshaw [18] and a monograph edited by Patai [19] also cover the synthesis and properties of crown ethers. More recent reviews deal with the use of crown ethers as chemosensors [20, 21], potential antitumor agents [22], molecular wires [23], or carriers for the separation of metal ions in liquid membrane processes [24],... 

Arrhenius, T. S., Blancharddesce, M., Dvolaitzky, M., Lehn, J. M., Malthete, J., Molecular devices - caroviologens as an approach to molecular wires synthesis and incorporation into vesicle membranes. Proc. Natl. Acad Sci. U. S. A. 1986, 83, 5355-5359. 

L. A., Hall, M.J., Alpin, R.T. and Anserson, H.L. (2000) Insulated molecular wires Synthesis of conjugated polyrotaxanes by Suzuki coupling in water. Angewandte Chemie (International Ed. in English), 39, 3456-60. 

The group of Professor Nazario Martin developed the synthesis of several donor-acceptor arrays containing -conjugated oPPEs of different length linking -extended tetrathiafulvalene (exTTF) as electron donor and C o as electron acceptor. Thereby, they systematically increased the length of the molecular wire from the monomer to the trimer. A detailed description of the corresponding synthesis is described elsewhere [8]. 

As it was pointed out, the beauty of organic chemistry is that simple changes used during the synthesis of molecular wires yields products with vastly different physical properties. Even minor alterations, such as the exchange of the donor moiety turned out to strongly affect the conduction behavior of the wires. Hence, the first molecular wire(s) that eventually might appear in commercial devices may bear no resemblance with those we have discussed. Thus, research in this area can still yield much fruit. 

The reaction of thioxanthone with various 3-thienyllithium compounds is the initial step in the synthesis of the diols such as 602 from which the bis(thioxanthylium) dication 603 is obtained. This species functions as a reversible redox pair with its reduction product, the hexaarylethane, creating an electrochromic system in which electron transfer brings about bond making and bond breaking. These oligomers 604 may be considered to be a new class of molecular wires (Scheme 238) <2004OL2523>. 

Maskus and Abruna [17] functionalized terpyridine (tpy) ligands with thiol groups. These ligands can be employed for Co2+-bridged molecular wires. The synthesis proceeds according to Scheme 10.19. After deprotonation, 59 was alky-... 

Double helical DNA is a water-soluble polymer that contains an electronically well-coupled stack of aromatic heterocyclic base pairs. This review describes efforts in our laboratory to characterize electron-transfer reactions between transition metal complexes bound by intercalation within the 7r-stack of DNA. Much information is available concerning the structure, synthesis, and methods of characterization of this polymer. Also, research in our laboratories has been directed toward describing the photophysical and photochemical properties of metal complexes bound to DNA. Using these metal complexes to probe the DNA 7r-way, we are now in a position to ask Is DNA a molecular wire ... 

Conductive polymers have received increasing interest in the last decade due to their potential applications. The synthesis of molecular conductors, for example, is a field of intensive research with the purpose of producing objects in the nanometer scale. Therefore, control of the morphology of conducting polymers is very challenging for the production of molecular wires (nanowires) or tubes. Appropriate templates for the confined polymerization of conductive polymers are required to give them a controlled shape and dimension. 

A considerable amount of work has been done in this area, which has been spurred in part by interest in the synthesis of multimetallic complexes in which the metal atoms are connected by unsaturated chains of several carbon atoms that may serve as molecular wires. The initial and still most widely employed synthetic route to vinylidene complexes involves addition of four equivalents of a triaUcylphosphine (T = PPrj hereafter unless otherwise... 

C.F. Vannostrum, S.J. Picken, A.J. Schouten, R.J.M. Nolle, Synthesis and Supramolecular Chemistry of Novel Liquid-Crystalline Crown Ether-Substituted Phthalocyanines Toward Molecular Wires and Molecular lonelectronics , J. Am. Chem. Soc., 117, 9957 (1995)... 

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