Tt-conjugated backbone

Very recently, the first metathesis reaction was utilized to synthesize a new type of photorefractive polymers, based on poly(1.6-heptadiyne) derivatives, that contain both a carbazole moiety as a hole transporter and NLO chromophores. attached to TT-conjugated backbones. Photorefractive polymers based on the previous works for the photoconductivity of poly(1.6-heptadiyne) derivatives containing a carbazole moiety and electrooptic activity of poly(1.6-heptadiyne) derivatives containing NLO chromophores were developed.Herein, all functional groups are covalently linked to the polymer backbone. 

Electron-withdrawing side chains are able to withdraw electron density firom TT-conjugated backbones and the energy level of the material is lowered. Similar to electron-donating moieties, electron-withdrawing side chains can also generate intramolecular interactions. 

During recent years, various research groups have continued to use the site isolation property of dendrons to prepare optoelectronically active (tt-conjugated) backbones, mostly via metal-catalyzed step-growth mechanisms. It is interesting... 

Imidazole as a parent Tt-conjugated backbone in charge-transfer chro-mophores 12BJ025. 

Figure 1.9 Polaron and bipolaron formation on tt-conjugated backbone of polypyrrole.

A first demonstration of the feasibility of this strategy was provided by a series of PTs (45-48) in which substituted phenyl groups are linked to the 3-position of the thiophene ring by means of an oxabutyl spacer. The electronic and steric decoupling of the phenyl rings from the TT-conjugated backbone is confirmed by the invariance of the absorption maximum at 520 nm, a value characteristic of extensively conjugated PTs [66,89]. However, as shown in Fig. 12.9, the resolution of the vibronic fine... 

The aforementioned chromisms obviously indicate that no matter what processes and driving forces are responsible, the conformational change or transition of the TT-conjugated backbone is the major origin of the dramatic color change. In this... 

Miteva, T., et al. 2000. Interplay of thermochromicity and liquid crystalline behavior in poly(p-phenyleneethynylenejs tt-tt interactions or planarization of the conjugated backbone Macromolecules 33 652. 

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