Conjugated aromatic units

A striking example of the interplay between 37t-jt and 3MLCT states comes from Castellano s group, who investigated complexes incorporating acetylides bound to more highly conjugated aromatic units such as 1-pyrene,... 

Recently, polyimines include the synthesis of long alkoxy (Cg-Cig) side chain derivatives [188,189], which are presumably soluble to some extent in organic solvents and derivatives containing fluorene cardo unit [190]. Trifluoromethyl groups [191] in the polymer backbone provide solubility in organic solvents. Studies of the electrical conductivity of doped conjugated aromatic polyimines and alkoxy derivatives have been reported [188], and the values are in the range of 10 to 10 S/ cm. 

The conversion of higher substituted to less substituted olefins is not favored thermodynamically. This obstacle can be overcome when the newly formed C=C bond gains stabilization by conjugation with another double bond, e.g. C=0, or an aromatic unit, or by equilibration into a more stable product in a consecutive reaction. The E-Z geometry of the starting olefin may have a significant effect on the configuration and enantioselectivity in the product. 

The most striking example are two polymer series with very large conjugated aromatic systems, prepared by Stille et al. (1968). The structural unit of these polymers is the following ... 

A special class of conjugated systems are those containing triple bonds and aromatic units as part of the bridging ligand and schematically represented by the... 

The synthesis of conjugated polymers is highly dependent on the effective carbon-carbon single bond generation between unsaturated carbons in aromatic molecules. Aromatic units in conjugated polymers can be benzene, aniline, pyrrole, thiophene, carbazole, naphthalenediimide, perylenediimide (PDI), or their derivatives, etc. Although monomers are various, their synthetic methods can be mainly classified into chemical and electrochemical polymerizations. Chemical polymerization includes chemical oxidative polymerization and metal-catalyzed coupling condensation. 

Adding one thienyl group on both sides of the BT converts BT into DTBT, which has a few more advantages when compared with the original BT unit. The two flanking thienyl units eliminate the otherwise severe steric hindrance between the BT unit and donor aromatic units, which can increase the planarity and conjugation of the polymer backbone. It... 

Conjugated poly(arylene-vinylene)s that contain triphenylamine, carbazole, or phenothiazine as aromatic units in the backbone have been synthesized... 

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