Arylene vinylene derivatives

Polyfarylene vinylene)s form an important class of conducting polymers. Two representative examples of this class of materials will be discussed in some detail here. There are poly(l,4-phenylene vinylcne) (PPV) 1, poly(l,4-thienylene viny-lenc) (PTV) 2 and their derivatives. The polymers are conceptually similar PTV may be considered as a heterocyclic analog of PPV, but has a considerably lowci band gap and exhibits higher conductivities in both its doped and undoped stales. The semiconducting properties of PPV have been shown to be useful in the manufacture of electroluminescent devices, whereas the potential utility of PTV has yet to be fully exploited. This account will provide a review of synthetic approaches to arylene vinylene derivatives and will give details an how the structure of the materials relate to their performance in real devices. 

Poly(arylene vinylene) derivatives were prepared by Wittig reaction of diphosphonium compounds(I and V), and dialdehyde compounds , Ill,and IV) as shown in Figurel. When I and II, I and IE, I and IV, and V and II are used, soluble alternating copolymers of (A), (B), (C), and (D) are obtained respectively(16,17,18). The diphosphonium compounds were prepared using triphenylphosphine and... 

A number of poly(arylene vinylene) (PAV) derivatives have been prepared. Attachment of electron-donating substituents, such as dimethoxy groups (structure 19.3), acts to stabilize the doped cationic form and thus lower the ionization potential. These polymers exhibit both solvatochromism (color changes as solvent is changed) and thermochromism (color is temperature-dependent). 

Extended ji-conjugated systems containing the 1,2-arylethene or stilbene scaffold and also the structurally related poly(arylene-vinylenes) have already established their utility as functional materials [44a, 48], As a consequence, higher substituted derivatives such as 1,1,2-triarylethenes could be interesting targets with unexpected new properties. 

Haloarene derivatives used for coordination polycondensation are primarily represented by halostyrenes and haloarylacetylenes which undergo selfcoupling to poly(arylene vinylene)s [scheme (2)] and poly(aryleneacetylene)s [scheme (3)] respectively, and by dihaloarenes which, mainly in a combination with alkenes or divinylarenes and acetylenes or diacetylenes, undergo crosscoupling to poly(arylene vinylene)s [schemes (4) and (5)] and poly(arylene acetylene)s [schemes (6) and (7)] respectively [2] ... 

After fundamental stupes on soluble RO-PPV derivatives(9), we have focused on the synthesis of highly luminous polymers and fabrication of highly efficient devices to commercialize P-LED. Taking exciton confinement and charge transporting into account, we have copolymerized various kinds of arylene vinylene units to introduce structural and energetic irregularity into poly(arylene vinylene). 

Poly(arylene vinyene)s (PAVs) represent the most widely studied group of electroluminescent polymers. The parent compound poly(para-phenylene vinylene) (PPV, 1, Fig. 6.1) [5] is insoluble and so must be processed as a precursor polymer but derivatives such as MEH-PPV (2) [6] with solubilizing alkyl, aryl, silyl, or al-koxy chains show good solubility in organic solvents and so can be readily processed by techniques such as spin casting. By appropriate choice of substituents... 

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