Naphthalene solvent effects

Catalan J, Perez P, Laynez J, Garcia-Bianco F (1991) Analysis of the solvent effect on the photophysics properties of 6-propionyl-2-(dimethylamino)naphthalene (PRODAN). J Fluor-esc 4 215-223... 

The silver(I)-mediated electrocyclic ring opening of halocyclopropanes has been used to induce extensive skeletal rearrangements in gcm-dibromospiropentanes, providing rapid construction of naphthalenes and/or indenes (Scheme4.21 ).34 A variety of Lewis acids, Brpnsted acids, and solvent effects were carefully examined before optimal conditions were identified. It was found that subjection of spirocycle 60 to silver acetate in trifluoroacetic acid afforded rearrangement products 61 and 62 in moderate to good yields. The proposed mechanism of the reaction is illustrated in Scheme 4.21. 

Natural sunlight induced photooxidation of naphthalene in aqueous solution has also been reported by McConkey et al. to produce six major products including 1-naphthol, coumarin, and two hydroxyquinone [9]. The authors proposed that the initially formed 2 + 2 and 2 + 4 photo cyclo addition products undergo subsequent oxidation and/or rearrangement to form the observed products [9]. Grabner et al. have studied solvent effects on the photophysics of naphthalene and report that fluorescence lifetime decreases by a factor of 2.5 in aqueous solution compared to organic solvents (e.g. ethanol, hexane, acetonitrile) [10]. Based on the observed differences in naphthalene excited triplet state properties in aqueous and organic media, the decrease... 

Another example of intramolecular CT complex formation is provided by trans-4-dimethvlamino-4 -(1-oxobutvl)stilbene Solvent effects on the spectrum give a value of 22D for the excited state dipole moment. The effect of electric field on the fluorescence of 4-(9-anthry1)-N.N.-2.3,5,G-hexamethy1-aniline shows this compound forms an excited state whose dipole moment does not change with solvent . Chiral discrimination in exciplex formation between 1-dipyrenylamine and chiral amines is very weak . In the probe molecule PRODAN (6-propionyl)-2-(dimethylamino)—naphthalene the initially formed excited state converts to a lower CT state as directly evidenced by time-resolved spectra in n-butanol. Rate constants for intramolecular electron transfer have been measured in both singlet and triplet states of covalently porphyrin-amide-quinone molecules . Intramolecular excimer formation occurs during the lifetime of the excited state of bis-(naphthalene)hydrazides which are used as photochemical deactivators of metals in polyethylene . ... 

T.J. Kauppila, T. Kuuranne, E.C. Meurer, M.N. Eberlin, T. Kotiaho, R. Kostiainen, Ionization and solvent effects in APPI of naphthalenes. Anal. Chem., 74 (2002) 5470. 

The systems studied were pyrene in SCF CO2, ethylene and CHF3 and naphthalene, dibenzofuran and carbazole in SCF C02 The spectra yield information on both solute/solvent and solute/ solute interactions. A typical spectrum of a dilute pyrene sample is shown in the lower half of Figure 7. Pyrene was chosen for the initial experiments because it has been extremely well investigated in organic liquids and the solvent effect on the spectra is well documented (29). 

Solvent effects Birch reduction. 1,2-Dimethoxyethane (Glyme) and Dimethyl ether (see Naphthalene-Sodium), Dimethylformamide. Dimethyl sulfone. Dimethyl sulfoxide. Diphenyl sulfoxide. Ethylene glycol. N-EthylmorphoUne. Hexamethylphosphoric triamide. Methylal. Methylene chloride. Methyl ethyl ketone. N-Methyl-2-pyrrolidone. Nitrometbane. Nitrosyl chloride. Phenetole. Tetrahydrofurane. Tetramethylene sulfone. Tetramethylene sulfoxide. Triethanolamine. Triethyl phosphate. Trifluoroacetic acid,... 

Solvent effects are sometimes important in the hydrogenation of substituted naphthalenes, e. g. 2-naphthol [24]. Use of Rh-on-alumina catalysts in acetic acid results in a mixture of decalone and cis-decalol, whereas changing the solvent to methanol or ethanol gives ds-decalol as the predominant product. 

Polycyclic hydrocarbons are extremely reactive with ozone. For example, naphthalene reacted with ozone at a rate about 1500 times faster than benzene (Hoigne and Bader, 1983b), and higher polycyclic hydrocarbons such as phenanthrene, pyrene, and benzo[a]pyrene were also extremely reactive (Butkovic et al., 1983). The experiments of Hoigne and Bader also indicate that the rate constants for reaction of ozone with aromatic hydrocarbons in water were about 100 times greater than in nonpolar solvents such as CCI4. However, aliphatic compounds did not show such a profound solvent effect. 

Lepree, J. M., M. J. Mulski, and K. A. Connors. 1994. Solvent effects on chemical processes. 6. The phenomenological model applied to the solubility of naphthalene and 4-nitroaniline in binary aqueous-organic solvent mixtures. Journal of the Chemical Society-Perkin Transactions. 2, 1491. 

The last example in Table 6.13 is the Friedel-Crafts acylation of naphthalene (CioHg). Substitution is found at both C-1 (C-a) and C-2 (C-P). Presumably, these products form by pathways that are similar to those already examined. However, dramatic solvent effects on the product ratio have been reported and if the acylation is carried out in solvents that can form complexes with ethanoyl chloride (acetyl... 

Keto-Enol Tautomerism in 4-(phenyldiazenyl)naphthalen-l-ol Solvent Effect... 

Phenyldiazenyl)naphthalen-l-ol (2) is one of the first tautomeric compounds discovered [39] and, in spite of its limited practical applicability, is one of the most studied [40]. Its attractiveness is due to the lack of intramolecular hydrogen bonding, as for instance, in 4, which makes the tautomeric equilibrium very sensitive to changes in the solvent environment. Hence, this compound is a suitable model, as shown in Chapters 11 and 13, to test the description of solvent effects both theoretically and experimentally. At the same time, the shift in the position of the equilibrium, caused by the temperature, is, in most solvents, very small slight and relatively difficult to be processed [13]. 

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