Naphthalene groups

Conductivity differences were seen in a bistable [3]catenane closed-loop molecule, with a naphthalene group as one station, and tetrathiafulvalene as the second station, decorated by a tetracationic catenane salt that could travel on the catenane, like a train between two stations, making a nano-switch [141]. 

Poly(ethylene naphthalate) (PEN) is also completely analogous to PET except that it incorporates a naphthalene group in its main structure as opposed to a phenyl group. The naphthalene unit stiffens the backbone and gives PEN a higher glass transition temperature and improved mechanical properties when compared to PET (see Chapters 9 and 10). 

Although the Novolak resin of the w-cresol-benzaldehyde failed to show a marked increase in CF4 plasma etching resistance, the Novolak resins of hydroxy-naphthalene-hydroxybenzaldehyde showed a remarkable increase in the plasma etching resistance. The resist films also yielded excellent patterns when used together with a diazo-naphthoquinone sensitizer almost non-diluted AZ2401 developer had to be used for image development due to the hydrophobic nature of the naphthalene group. 

Balzani, Vogde et al. demonstrated for dendritic cyclam compounds that signalling units are dendritically amplified by increasing the number of peripheral fluorophores. Opportunities for these PET sensor systems exist in the combination of selective coordination sites with the dendritic architecture. The mechanism resembles that described above, but can be influenced by the introduction of dendritic units of different generations into the sensor system. The distance between the terminal naphthalene groups of the dendron and the receptor (ion as guest in the cyclam core) is of crucial importance for electron transfer (ET) (Fig. 8.15) [53],... 

Noyori s BINAP catalysts deserve special attention because their chirality is based on the bulkiness of the naphthalene groups, rather than on carbon or phosphorus asymmetric centers (Figure 3.28, inset) [77]. One of the many examples of asymmetric catalysis using BINAP is the synthesis of (—)-menthol, an important additive for flavors, fragrances, and pharmaceuticals. Starting from myrcene, the process is carried out by Takasago International on a multi-ton scale. The key step is the isomerization of geranyldiethylamine to (R)-citronellal enamine [78], which is then hydrolyzed to (R)-citronellal with nearly 99% ee. 

PEN is more rigid than PETE because naphthalene groups, which are larger than the phenyl groups present in PETE, serve as spacers between ethylene glycol-derived units. 

Diazotization.—Like aniline and other aromatic primary amines they undergo diazotization. The resulting diazo compounds undergo the various diazo reactions (p. 601) by means of which the naphthalene group becomes coupled as an azo compound with other naphthalene or benzene rings. These azo compounds are dyes. The most important dyes of this group are derived from mixed amino and sulphonic acid or mixed amino and hydroxyl derivatives of naphthalene and will be considered a little later. Not only, however, may the naphthylamines >deld diazo compounds and through them azo compounds but they may be coupled as azo compounds with a diazotized benzene compound. 

Illustrations of azo dyes containing naphthalene groups might be continued in very large number but this is undesirable as it would only tend to confuse the point to be emphasized, viz., that mixed amino or hydroxyl derivatives of naphthalene either by diazotization and coupling with other compounds, as in the case of fast red, or by coupling with... 

Dyestuffs which contain benzene and no higher hydrocarbon are mostly yellow, orange-yellow, or brown. By the introduction of a naphthalene group, red colouring-matters are formed, and blue and violet dyestuffs are obtained if the naphthalene ring occurs several times. 

Further studies by Lindner and Maier have shown that substitution of one of the cinchona alkaloid moieties in dimeric cinchona phthalazine-type CSPs with a bulky naphthalene group still allows to maintain the high enantioselectivity of separation. For example, enantioseparation of DNZ-protected P-neopentylglydne on mixed CSP 63 occurs with excellent selectivity, a = 34.2 [106]. 

PACN has been interpreted as slow exciton macromolecule in accordance with this work (No. 4 in Table III) and with the microstructure which prevents any close overlap of nearby naphthalene groups needed for efficient electron exchange interaction. 

Gaussian segment distribution for PUMA. Since the presence of the naphthalene groups could perturb the average chain conformation,... 

Since these blends are essentially PMMA in PMMA, the copolymers are approximately In -conditions (36). (The effect of the naphthalene groups Is discussed below.) True -conditions for a solid blend would be PMMA In a PMMA host of the same molecular weight. We do not expect that a host M of 120,000 results in a significant deviation from -conditions since. In a previous fluorescence depolarization experiment, nearly identical r(t) curves were obtained for a 20,000 M 2-VN/MMA copolymer in both... 

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