Perylene, cyclization

In this context it is important to keep in mind, however, that di(2-naphthyl)ethylene (2 + 2) and 3-styrylphenanthrene (3 +1) form pentahelicene on irradiation, but in the presence of iodine it cyclizes into benzo[g,h,i]-perylene 17). The second cyclization... 

No photoreactions, except incidental photodestruction are known for hexa- and higher helicenes. As already mentioned in 2.1.1. pentahelicene forms benzo[g,h,i]perylene on irradiation in the presence of iodine as an oxidizing agent. Remarkably, the symmetrical benzoderivative (111) does not yield a similar cyclization product. This is ascribed to the antibonding character of the ji-orbitals at C-(l) and C-(14) involved in the expected photoreaction as appeared from EHMO calculation 17b). 

A typical example involves the perylene monoimide donors described above. They have been used to construct antenna models in which up to eight perylene units were covalently bound to a zinc(II) porphyrin94. Osuka and coworkers windmill porphyrins also present excellent antenna complex building blocks (vide infra)95. In addition, several porphyrin wheel antenna complexes were prepared by template-assisted synthesis96,97 or self-aggregation98. Intramolecular cyclization of porphyrin dodecamers to a porphyrin wheel has also been achieved99. 

Related complexes of group 10 metals are accessible by an oxidative addition/reductive cyclization protocol, exploiting the inverse electron demand (Scheme 27) (Pt <2005JA13494>, Ni <20030M3604>). The nickel complex is thermally unstable, proceeding to perylene via a bimolecular reductive elimination or, in the presence of alkynes, delivering acenaphthylene derivatives by an insertion/reductive elimination pathway. 

Looking for new complexes, Yamaguchi et al. observed that a cyclic diaryltetrayne underwent rearrangement in the presence of 2.5 equiv of silver triflate to a difur-operylene, which was isolated in 30% yield. The reaction could be made nearly quantitative by addition of two other portions of silver triflate after 3 and 6h while stirring (Scheme 3.61). The formation of perylene proceeds by a complex silver-mediated process involving sp-sp and sp-sp2 cyclization.87... 

Absorption spectra of more than five-ring systems are compared in Table XII, where only the first and second (and third) bands are listed for simplicity. Pericondensation (195) to 2 shifts the absorption band more bathochromically than catacondensation (30) does. Cyclization of azonia-pentahelicene salt (180) to the corresponding azoniabenzo[g/n ]perylene salt (204) shifts the maximum absorption wavelength about 18 nm longer, similar to the annelation to form azoniahexahelicene salt (206). 

The attachment of a R3Si (31) or an biphenylyl (30) group enhances the electron affinity of a benzene ring. Such substitution permits biphenyl rings (33) or the triphenylene system (32) to be generated readily. Collateral evidence in support of radical-anionic intermediates in these reactions has been obtained (5). Another example of the intramolecular cyclization is the formation of perylene from 1,1 -binaphthyl. 

Along with cyclization effected by alkali and acidic reagents, high-condensed systems may be obtained by thermal treatment of the starting polynaphthoyl-enebenzimidazoles in an inert medium. Both cyclodehydration and cyclodecarboxylation processes are observed. As a result, the thermally treated systems contain both perylene and anthanthrone cycles. The thermal treatment is the optimal method of cyclization of polynaphthoylenebenzimidazole fibers and this is confirmed by the data in Table 30. 

The other ones are a soluble ladder conjugated polymer, composed of perylene diimides and thieno [3,2 b]thiophene was prepared recently by a synthesis via photo cyclization by irradiation with sunlight [224]. These soluble polymers, prepared for photonic applications, can be illustrated as follows ... 

Finally, the open form of the dyad (dyad 1-a) was synthesized by Suzuki coupling of the PDI part 6a and the TDI part 13 (Scheme 2, step g). The dyad 1-a was obtained in 60% yield after gel permeation chromatography (GPC). Due to its extended aromatic core, terrylene diimide shows a much lower solubility than its smaller homologue perylene diimide. Concerning the poor solubility of the TDI unit, the cyclization reaction was performed as the last step (Scheme 2, step h). As shown in Fig. 2, the perylene part is susceptible to hydrolysis, so the cyclization had to be performed rapidly (within 30 min). Cyclization using K2CO3 as base in ethanolamine completed the synthesis of the dyad 1. Besides imreacted 1-a, the... 

Two approaches were available for the preparation of quaterrylene bisimides, taking advantage of either intramolecular cyclization or intermolecular dimerization reactions. These two methods were developed independently in Mullen s and Langhals groups. As shown in Scheme 7, Mullen s intramolecular approach started from bromination of perylene monoimide 74, which was subjected to Yamamoto coupling reaction to produce precursor 76, and the quaterrylene bisimide 77 was... 

Two important polycycles produced prior to 1920 were perylene 19 (Fig. 1.2a) and pyrene 7, both of note as parent structures for numerous fused benzenoid analogs produced in the following decades. In 1910, Scholl, Seer, and Weitzenbock first produced perylene from an AlCls-mediated cyclization of naphthalene and/or 1,1 -binaphthyl under heat in low yield [19]. A subsequent success with improved yield occurred via treatment of 1,8-diiodonaphthalene with Cu powder. Weitzenbock was responsible for the first synthesis of pyrene in 1913 [20]. The five-step synthesis began with bromination of o,o -ditolyl followed by conversion into dicar-boxylic add 20 via a dinitrile intermediate (Scheme 1.7). Cyclization and Zn-dust distillation afforded the tetra-fused structure in a well-designed synthesis, confirming its structure through intermediate analysis. 

Cook s early research efforts focused on isolating coal-tar components [34], such as perylene and benzoperylene, as well as developing synthetic routes to previously isolated compounds. In contrast to the numerous Zn-dust distillation cyclizations,... 

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