Acenes synthesis

Using suitably substituted acetylenes as starting materials, super naphthalene and super triphe-nylene have been synthesized [45], The unsubstituted super acenes are insoluble solids. In order to obtain soluble derivatives, f-butyl groups were added to the periphery of the super acenes. Synthesis of super triphenylene is illustrated in Scheme 16.41 [45]. 

In 1993, Scherf and Chmil described the first synthesis of a ladder-type poly(pflra-phenylene-czs-vinylene) (116) [138]. On the one hand, ladder polymer 116 represents, a planar poly(phenylene) containing additional vinylene bridges on the other hand, it is a poly(phenylenevinylene) with aryl-aryl linkages in the polymeric main chain. The target macromolecules, as fully aromatic ladder polymers, are composed of all-carbon six-membered rings in the double-stranded main chain (an example of angularly annelated poly(acene)s). 

Generally, benzene and naphthalene derivatives show only little reactivity as dienes in Diels-Alder synthesis, contrary to anthracene and the higher acene derivatives which are frequently used as dienes. Exceptions are the reactions of benzene and naphthalene derivatives with highly reactive dienophiles such as dicyanoacetylene (DCA), which... 

We earlier recalled that one can build a huge number of molecules by simply assembling CeH rings, a scheme that was summarized in Table 1.4, and that a solid such as graphite can be obtained in this gedanken synthesis. Let us briefly discuss the case of linear acenes, which are linear polycyclic aromatic hydrocarbons (PAHs) composed of laterally fused CeHe rings. 

Finally, just a few words dedicated to the synthesis of polyphenylenes, extremely important polymers, and in particular substituted polyphenylenes such as PPV, which exhibit superb thermal and chemical resihence, semiconduchng properties upon doping and applicahons such as OLEDs. Contrary to their linear acenes counterparts, long polyphenylenes can be obtained e.g., by Bergman s method consisting in the thermal cycloaromatization of enediynes (Lockhart et al, 1981). 

IR (KBr) 3040 w, 2974 w, 1647 s, 1550 s, 1477 s, 1340 s, 756 s. The synthesis for AlLCl L = SalenCl, Acen, Salophen, ° Salen Bu, Salpen Bu, Salben Bu, Salo-phen Bu, Salomphen Bu is similar and leads to organic soluble compounds. The preparations for L = Salen, SalenCl, Acen, and Salophen are facilitated by the insolubility of the compounds, which precipitate essentially quantitatively from toluene. 

The compound [Al(Salen)(H20)2]Cl is not air-sensitive. It has mp 162-165°C dec. The cation is soluble only in water. IR (KBr) 3057 s (br) 1639 s, 1560 m, 1473 s, 1296 s, 814 m, 760 s cm . The synthesis and properties of the SalenCl and Acen derivatives are described in Ref. 7. Salophen, Salen( Bu), Salpen( Bu), Salben( Bu), Salophen Bu, and Salomphen Bu derivatives can also be prepared in a similar manner. In the solid state these compounds have been shown by X-ray crystallography to contain six-coordinate octahedral aluminum. The solvent molecules are trans to one another and the hgand copla-nar with the aluminum atom. The chloride anions are connected by hydrogen bonds to the solvents on the aluminum as well as additional solvent in the crystal lattice. 

In one synthesis of [V(acen)Cl(THF)] (4), a THF suspension of Na2acen is allowed to react with [VC13(THF)3].324 A second method involves reductive deoxygenation of [VO(acen)] (equation 9) once [VO(acen)] has been synthesized, it is a straightforward procedure. 

Lin and Tao used P(Z-Bu)3 for the synthesis of benzo[a]aceanthranylene core compounds (acen) 98. Pure red-emitting devices were fabricated using acen as both holetransporting and emitting materials [157]. Palladium-catalyzed aromatic C—N coupling reactions and cyclization were carried out in one pot in the presence of Pd(OAc)2 and r-Bu3P [157]. 

Nicolas, Y. et al.. Synthesis of a Thermally Stable Hybrid Acene-Thiophene Organic... 

Historically, boron sulfide was used to synthesize solid-state sulfides such as MS2X2 and MSX3 (M = Mo, W X = Cl", Br") but these compounds are of limited value as MoHM precursors. Its early applications in molecular OSCRs include the synthesis of VS(acen) (acen = Ar,AT -ethylenebis(acety-lacetonylideniminato)), MOS(ONC5Hjo)2 (M = Mo, W ) (Section 7.4.1.1.2), Tp MoS(S2CNR2) (Tp = hydrotris(3,5-dimethylpyrazolyl)borate R = alkyl and Tp MoSCl2 (Section 7.4.1.1.3) from their 0x0 analogues. 

Shot Synthesis of Alkyl-Substituted Acenes Using Carbonyl-Directed C-H and... 

Y. Mazaki and K. Kobayashi, Synthesis of tetrathieno-acene and pentathieno-acene - UV-spectral trend in a homologous series of thieno-acenes. Tetrahedron Lett., 30, 3315-3318 (1989). 

Higher members of the acene series have demonstrated to be a very difficult synthetic target. However, photochemical reactions can be carried out at a low temperature and are thus well suited for arriving to products of limited stability. A remarkable success has been the synthesis of octacene... 

Beyond Pentacenes Synthesis and Properties of Higher Acenes... 

Keywords Acenes Alternant hydrocarbon Polymer Spectroscopy Synthesis... 

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