Bis 2-naphthyl

Synthesis of Optically Active Poly(l,l -bi-2-naphthyl) 1654c... 

Polyt/f-esters), 41-43 Poly(l,l -bi-2-naphthyl) (Poly[BINAP]), optically active, 509-510, 513-514... 

Ph2CN2, 9-diazofluorene, bis(2-naphthyl)diazomethane, M62CN2 H, Ph, COPh, C02Et, PO(OMe)2, POPhz. 

There are fewer UV absorbance studies of dinaphthylalkanes. Chandross and Dempster 9) have studied l,2-bis(l-naphthyl)ethane, l,3-bis(l-naphthyl)propane and l,4-bis(l-naphthyl)butane, as well as l,3-bis(2-naphthyl)propane and the compound l-(l-naphthyl)-3(2-naphthyl)propane. The latter had the same absorbance spectrum as a 50/50 mixture of 1- and 2-methylnaphthalene, while the bis compounds were shown to have the same absorbance spectrum as the corresponding methylnaphthalene isomer. These studies were made in a 90/10 v/v mixture of methylcyclohexane/isopen-... 

De Schryver and co-workers u> have confirmed Chandross result for the UV absorbance of l,3-bis(2-naphthyl)propane. Nishijima et al.12) have stated that the absorbance spectrum of meso- and dl-2,4-bis(2-naphthyl)pentane and of the compounds l,3-bis(2-naphthyl)A, where A = propane, butane, pentadecane, and 5-phenylpentane, is similar to the absorbance spectrum of 2-ethylnaphthalene. Finally, an unusual result has been obtained by De Schryver et al.13> for the compound bis(l-(2-naphthyl)ethyl)ether. The meso compound gave a lower value of ID/IM, the ratio of excimer to monomer fluorescence intensities, under excitation at 304 nm relative to excitation at 285 nm, while the dl compound had no such excitation dependence. The UV absorbance spectra of these compounds were not reported, however. 

It is clear that the sandwich-dimer studies discussed above apply to P1VN, not P2VN, since no photodimerization has been observed in bis(2-naphthyl)alkanes 10 and ethers 39). Nevertheless, the UV absorbance of naphthyl sandwich dimers, like that expected for [3.4] or [3.5] naphthalenophanes, differs from that of isolated molecules only for X > 325 nm. The same slight difference in UV absorbance probably occurs for excimer-forming sites. 

All the above compounds yield excimer fluorescence when excited in room-temperature solution. However, because the rotational potential of the C—X bond and the nonbonded interactions of the substituents of the X atom differ from those of the C—C bond 126), the amount of excimer fluorescence from R(C—X—C)R differs from that of R(C—C—C)R. The heteroatom X can also influence the rotational state of the side groups R, as illustrated by the formation of the anti-photodimer in bis(l-naphthylmethyl)ether u2), but not in l,3-bis(l-naphthyl)propane 10). Finally, compounds having n 3 may exhibit excimer fluorescence, if the linkage contains one or more heteroatoms. For example, the—C—O—C—C— linkage in a,to-bis(2-naphthyl) compound allows excimer fluorescence to be observed in room-temperature solution39). 

Only one excimer fluorescence peak and lifetime were observed l2) for R—CH2— CH2-CHX-R, where R = 2-naphthyl and X = H 121>, methyl, dodecyl, or p-phenylethyl. The same was also true for meso- and d/-2,4-bis(2-naphthyl)pentane12). A recent report128) attributing the fluorescence peaks at 345, 363, and 381 nm in the spectrum of poly(2- er/butyl-6-vinylnaphthalene) to a second excimer species must therefore be considered invalid. The polymer undoubtedly contains an in-chain impurity with vinylnaphthalene conjugation, as discussed in Section 2.1.9.2 for a similar claim involving P2VN 33). 

The conformational statistics of asymmetric vinyl chains such as P2VN are well-known 126). The rotational conformers of isotactic (meso) dyads are entirely different from those of syndiotactic (dl) dyads. Frank and Harrah132) have described each of the six distinct conformers for meso and dl dyads, using the t, g+ and g nomenclature of Flory 126). Excimer-forming sites (EFS) are found in the tt and g g+ meso states, and in the degenerate tg , g t dl state. Because the rotational conformers of compounds such as l,3-bis(2-naphthyl)propane do not match those of either the iso-or syndiotactic dyads of P2VN, the propane compounds make poor models of aryl vinyl polymers. However, the rate constants of fluorescence and decay of the intramolecular excimer in polymers can usually be determined from the propane compounds (but see the exceptional case of PVK and its models133)). 

Recent conformational calculations made on the 2,4-bis(2-naphthyl)-pentanes 1371 gave results similar to the diphenylpentanes. The tt state (EFS) in the 2-naphthyl meso isomer was found to be 2.3 kcal/mole higher than the tg, g+t state, consistent with a larger repulsion between naphthyl rings than for phenyl rings. It is apparent from molecular models, and has been confirmed by Seki et al.138,139), that the... 

To determine whether QD mid QD/QM for the intramolecular excimer differ from the corresponding inteimolecular values, the fluorescence behavior of excimer-forming bis(2-naphthyl) compounds has been collected in Table 9. The experimentally-measured excimer and monomer quantum yields [Pg.64]

For the intramolecular excimer of bis(2-naphthyl) compounds, the value QD = 0.15 0.03 is obtained in room-temperature solution Qd/Qm = 0.55 0.15 is the quantum yield ratio corresponding to QM = 0.27. We note that Q = 0.125 was obtained for a P2VN sample having Mw = 270,000, for which (pD = 0.12 and intramolecular excimer fall within the range of values given for the intermolecular excimer in Table 8. Unfortunately, the solvent 95% EtOH has not been utilized with the bis(2-naphthyl) compounds, so a direct comparison with the 2-methylnaphthalene data is not possible. 

Values of kD which appear in Table 9 were obtained by the usual biexponential decay analysis37) adapted from the intermolecular version due to Birks 7l). Despite observations made for meJo-bis( 1 -(2-naphthyl)-ethyl) ether13) and l,3-bis(2-naphthyl) propane 159) of one rise time and two decay times in the transient fluorescence of the excimer, there have been no reports confirming this complication for the compounds... 

Finally, Table 9 shows that kFD of the intramolecular excimer has the value 2.0 0.3 x 106 s 1 for all the bis(2-naphthyl) compounds. If kFM is assumed to be 4.9 x 106 s-1, the same as for 2-ethylnaphthalene, then kFD/k,.M = 0.41. Comparison of the intermolecular data in Table 5 with the intramolecular values for k, and kFD/kpM indicates the similarity of the two types of excimers. Also, the similarity in Qd and kD holds for the excimers of meso and < -2,4-bis(2-naphthyl)pentane, compounds whose ground-state conformational behavior is quite different. 

As noted earlier, the limiting lifetime of pyrene excimer fluorescence from concentrated solutions in PS and PMMA glasses was found to be the same as that of pyrene in cyclohexane solution. There have been no similar studies of naphthyl compounds in rigid glasses. Values of k and Q for the [2,6]-naphthalenophanes have not yet been determined for any solvent system. The bis(2-naphthyl) compounds have not been quantitatively characterized in rigid matrices, probably because excimer fluorescence is weak and difficult to detect under such conditions. Given such limited data, it can only be assumed that the values of QD and kD of 2-naphthyl excimers remain the same in rigid solution as in fluid solution. 

The value of [Pg.69]

In an earlier study <1984JA6087>, the product of photosenzitized oxygenation with 9,10-d icy a noanthracene (DCA) of 1- and 2-naphthyl cis- and //war-substituted epoxides could be proved by X-ray crystallography to be the cA-trioxolane 27, which is a meso form. The corresponding /razw-trioxolane was obtained by the ozonation of cis-1,2-bis(2-naphthyl)ethene and it could be resolved into enantiomers 28 and 29 on a chiral high-performance liquid chromatography (FIPLC) stationary phase (Scheme 2). 

Organo tellurium halides, also named organo tellurenyl halides, are in principle easily accessible through controlled halogenolysis of diorgano ditellurium compounds. However, 2-naphthyl tellurium iodide, prepared in 19592 from bis[2-naphthyl] ditellurium and iodine, remained the only compound of this type until 1971/72, when a series of ortho-carbonyl substituted phenyl tellurium halides were synthesized3-4. Aryl tellurium halides without substituents in the ortho-position to tellurium were isolated and characterized in 1975s. 

Bis[2-naphthyl] Ditellurium1 Disodium ditclluridc is prepared by heating equimolar amounts of tellurium and sodium in hexamethylphosphoric triamide under nitrogen. To this solution are added 2 mol-equiv. of 2-chloronaphthalene and the mixture is heated at 130-170° for 16-24 h yield 20% two polymorphs m.p. 116-118° (hexane), m.p. 122-124° (hexane/benzene, 5/1). 

Bis[4-methylphenyl] ditellurium, bis[4-methoxyphenyl] ditellurium, and bis[4-ethoxy-phenyl] ditellurium, but not diphenyl or bis[2-naphthyl] ditcllurium, reacted with 2-(phenyliodonio)-benzoates producing compounds with two vicinal aryltelluro substituents in the aromatic ring. The reactions are postulated to proceed via the thermally generated singlet benzyne and concerted addition of the diaryl ditellurium compounds. 

Chloro-2-butyl 2-naphthyl tellurium dichloride and Raney nickel under similar conditions yielded bi[2-naphthyl] ... 

Enhancement in the performance of OLEDs can be achieved by balanced charge injection and charge transport. The charge transport is related to the drift mobility of charge carriers. Liu et al. [166] reported blue emission from OLED based on mixed host structure. A mixed host structure consists of two different hosts NPB and 9,10-bis(2 -naphthyl)anthracene (BNA) and one dopant 4,4 -bis(2,2-diphenylvinyl)-l,l -biphenyl (ethylhexyloxy)-l,4-phenylene vinylene (DPVBi) material. They reported significant improvement in device lifetime compared to single host OLEDs. The improvement in the lifetime was attributed to the elimination of heterojunction interface and prevention to formation of fluorescence quenchers. Luminance of 80,370 cd/m2 at 10 V and luminous efficiency of 1.8 cd/A were reported. 

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