Oligoenes, conjugated

SCHEME 50. Synthesis of conjugated oligoenes via an iterative hydrozirconation-cross-coupling tandem process149... 

Uan, T., and Yanagida, S. (2004) Phenyl-conjugated oligoene sensitizers for Ti02 solar cells. Chem. Mater., 16, 1806-1812. 

Figure 9. Gap between HOMO and LUMO orbital energy for various conjugated systems oligoynes, oligoenes, and fullerenes. The upper scale is for the oligoynes and oligoenes and the lower scale for fullerenes.

It should also be recalled that the numbers of possible stereo- and regioisomers of dienes and oligoenes increase exponentially as the degree of oligomerization increases in sharp contrast with oligoynes, as indicated in Table 3.7 for conjugated... 

Applications of Types V-VIII Alkenyl Reagents to the Synthesis of Natural Products Containing Conjugated Di- and Oligoenes... 

Scheme 3.32 Syntheses of trisubstituted alkene-containing conjugated di- and oligoenes from 1,1-dibromoalkenes by Pd-catalyzed Negishi alkenylation [143-146].

Figure 4-4. Schematic molecular orbital energy levels, (a) Neutral conjugated system (b) its radical cation (c) its dication (d) neutral radical of an odd oligoene. HOMO, highest occupied molecular orbital LUMO, lowest unoccupied molecular orbital SOMO, singly occupied molecular orbital ...

The hydrozirconation-Pd-catal5fzed cross-coupling tandem process described above has been applied to the synthesis of a, cu-difunctional conjugated oligoenes that either have been or... 

HOMO-LUMO transition is the dimerization amplitude u = i/c=c - dc-c- This parameter is directly related to the CL and is particularly useful in discussing the conjugational properties of truns-PA and oligoenes. 

Yet, compared to the other x-systems, the acyclic linear polyenes, and the cyclic oligoenes (i.e., the annulenes), cross-conjugated molecules have lived in the shadows so far. Acyclic linear polyenes are encountered widely in fatty acid, polyketide, and terpenoid natural product domains and the ultimate polyene, polyacetylene is a conductive polymer that was the focus of the 2000 Chemistry Nobel Prize. The annulenes played crucial roles in the development of practical and theoretical organic chemistry (aromatic and antiaromatic compounds), and serve as pivotal bulk chemicals in industry (benzene, toluene, the xylenes, styrene, etc.). 

This useful synthetic methodology can be applied for the construction of not only the triarylethene framework but also CF3-containing enediyne derivatives, which can be used to study the mechanism for their function in antitumor antibiotics, such as dynemicin, neocarzinostatin, and esper-amicin as well as to synthesize oligoenynes, oligoene-diynes, and / -conjugated polymers for electronic and photonic applications. As shown in Scheme 26.58,... 

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