Jr-conjugation

Ajayaghosh A, George SJ, Schenning APHJ (2005) Hydrogen-Bonded Assemblies of Dyes and Extended jr-Conjugated Systems. 258 83-118 Akai S, Kita Y (2007) Recent Advances in Pummerer Reactions. 274-. 35-76 Albert M, Fensterbank L, l.acote E, Malacria M (2006) Tandem Radical Reactions. 264 1-62 Alberto R (2005) New Organometallic Technetium Complexes for Radiopharmaceutical Imaging. 252 1-44... 

B. Jiang, S.-W. Yang, and W.E. Jones, Jr., Conjugated porphyrin polymers control of chromo-phore separation by oligophenylene vinylene bridges, Chem. Mater., 9 2031-2034, 1997. 

Ajayaghosh A, George SJ, Schenning APHJ (2005) Hydrogen-Bonded Assemblies of Dyes and Extended jr-Conjugated Systems. 258 83-118 Alberto R (2005) New Organometallic Technetium Complexes for Radiopharmaceutical Imaging. 252 1-44... 

While the jr-conjugation ability of phosphorus compounds does not seem to depend on the size of... 

The 2PA cross section also increases when the jr-conjugated bridge is extended, as shown for D-tt-D o, o -diphenylpolyenes q.2, q.6-q.9 in Table 1 the value of <5max increases from 2.0 x 10 to 1.3 x 10 GM going from 1 to 5 double bonds in the chain [94]. A red shift in the position of the 2PA peak accompanies the increase in cross section. A similar trend in A ax and 5max is observed when the chain length is increased from q.2 to q.lO and q.l2 by adding phenylene-vinylene units (Table 2). The increase in cross section is... 

From a structural point of view, the N-acyl group in heterocyclic systems is closely related to amides, in which Jr-conjugation between the carbonyl group and nitrogen lone pair imposes a twofold barrier for rotation around the exocyclic C—N bond. The equilibrium distribution of s-cis and s-trans... 

The close resemblance of the para carbon shift of the silyl-substituted cations 372-375 (168-170 ppm) to that of the mesitylallenyl cation 385 (165.9 ppm), which in addition to aryl conjugation is stabilized by /i-allyl resonance, shows that hyperconjugative interaction of a jS-C—Si cr-bond with the vacant 2p(jr) orbital on C+ in 372-375 is about as efficient as /l-jr-conjugation in 385. 

In contrast, anodic oxidation of tetra-2-(/T-methylterthienyl)silane provides polythiophene without desilylation9. The polymer has a 3D electroactive jr-conjugated system (equation 5). 

While there are many polymerization reactions utilized to produce a variety of jr-conjugated polymers, four general C-C bond-forming schemes have afforded many of the polymers found in the literature and continue to be valuable routes. These four methodologies, namely electrochemical synthesis, Lewis acid-in-... 

Fig. 4.2 P-based building blocks used for the construction of jr-conjugated systems.

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