Oligo-phenylene vinylene

Geisler, T. Pedersen, K. Petersen, J. C. Third-harmonic Generation in Substituted Oligo-phenylene Vinylenes and Organic Square Planar Nickel Complexes. In Notions and Perspectives of Nonlinear Optics Keller, O., Eds. World Scientific Singapore, 1996 pp 580-585. 

A totally different route based on dehydrogenation of a saturated polymer precursor was introduced by Francois et al. [49] (Scheme 2.9). The method is based on anionic copolymerization of cyclohexadiene with styrene, followed by oxidation with chloranil. Due to possible coupling of two styrene (or two cyclohexadiene) molecules, a block copolymer, containing oligo(phenylene vinylene) units separated by oligo(phenylacetylene) and oligo(phenylene) blocks, is obtained. To the best of our knowledge, it was, so far, used only in the synthesis of phenyl-substituted PPV 10. 

Lahti and coworkers [212] reported a series of meta-linked oligo(phenylene vinylene) block copolymers 181a-c. A mem-linked phenylene unit imposed an additional hypsochromic shift on the emission of these segmented polymers. The PL maxima were found at 399-416 nm, but a significant (ca. 70 nm) red shift was observed for EL spectra (ITO/polymer/Ca/Al) (Chart 2.39). 

At Kodak, researchers used a rigid adamantane moiety to separate the luminescent oligo(phenylene vinylene) blocks (copolymers 182, 183) [213], The EL color can be tuned from blue (AEL = 470 nm) to green (AEL = 516 nm) by replacing a phenylene unit in 182 for 2,7-naphthylene (183). A very low turn-on voltage of 5.5 V (as for this class of materials) was achieved in the device ITO/182/Mg Ag, but no EL efficiency was reported (Chart 2.40). 

Nonconjugated Polymer Containing Oligo(Phenylene Vinylene)... 

The conjugation length and the emission color of PPV-type materials can be also controlled by using short oligo(phenylene vinylene) units as pendant substituents in nonconjugated polymer chain. The advantage of such an approach is the possibility to use well-established... 

M.R. Robinson, S. Wang, A.J. Heeger, and G.C. Bazan, A tetrahedral oligo(phenylene vinylene) molecule of intermediate dimensions effect of molecular shape on the morphology and electroluminescence of organic glasses, Adv. Funct. Mater., 11 413 419, 2001. 

We recently synthesized a series of oligo(phenylene vinylene) (OPV) molecules, shown in Figure 5.5.39 Using known assembly procedures40 SAMs were made of compounds 2 and 3 to assess their efficacy in surface adhesion. The thioacetate is easily deprotected to... 

FIGURE 5.5. Three oligo(phenylene vinylene) molecules 2-4 synthesized as potential molecular electronic components. 

The self-catalyzed model is a simplification of the actin polymerization model of Oosawa and Kasai (1962) [and more recent elaborations of it (Niranjan et al., 2003)], and both equilibrium constants K and Kn, and hence the free energies g and ga can in principle be obtained by fitting the theory to assembly experiments. Typical values of g for, for example, actin vary between —10 and —20 kBT and ga between +2 and +3 kBT (Oosawa and Asakura, 1975 Oosawa and Kasai, 1962). For the biomimetic compound oligo(phenylene vinylene) similar to compound 2 shown in Figure 6, dissolved in alkane solvents, similar values were found for g but much larger ones for ga of +8 to +10 kBT, making the supramolecular polymerization of this compound an extremely highly co-operative process (Jonkheijm et al., 2006). 

To date, there are only a few molecules for which this has been done systematically, in particular the discotic and oligo(phenylene vinylene) compounds shown in Figure 6 (van Gestel et al., 2003 Jonkheijm et al.,... 

Oligo-Phenylene Vinylene A Model System for Donor—Acceptor Interactions... 

Oct-OPV5 and Ooct-OPV5 were prepared following a procedure that was used to prepare terf-butyl-end-substituted oligo(phenylene vinylenes) [43], Benzyltri-phenylphosphonium bromide was lengthened by a styryl unit via a Wittig reaction with 4-methylbenzaldehyde. The methyl group of the stilbene was functionalized by bromination with A -bromosuccinimide (NBS). The phosphonium salt of the stilbene was obtained by a subsequent reaction with triphenylphosphine in toluene. 

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