Napthalene spectra

N—[2—(5,5-Diphenyl-2,4-imidazolidinedion-3-yl)ethyl]-7-acetoxy-1-napthalene sulfonamide This substituted sulfonamide has a molecular weight of 543 daltons, and in the positive LD mass spectrum two ions at m/z 566 and m/z 582, corresponding to attachment of sodium and potassium ions, respectively, were observed. No significant photodissociation pathway other than loss of the attached cation was seen for either of these two ions. In the negative ion LD mass spectrum, an ion at m/z 500 originating from loss of C HjO was observed. This ion photodissociated when irradiated by the (gated) cw laser to produce an ion at m/z 251 (see Figure 9) (Equation 6). 

The proton NMR data, together with the CP/MAS NMR spectrum and the elemental analyses have been used to calculate two Important structural parameters, a and aru/ ar sed on the equations of Brown and Ladner (12) The parameter, a, is defined as the degree of substitution of the aromatic systems, i e., the fraction of the available ring carbon atoms which bear substituents and H u/ ar is defined as the ratio of hydrogen to carbon in an hypothetically unsubstituted aromatic material The value of a is found to be 0 8 This value is very close to that expected for a napthalene system... 

Coloration and absorption bands have been early noticed in the author s laboratory, when napthalene and anthracene vapor were adsorbed under high vacuum conditions on to a silica-alumina catalyst. They had been ascribed at that time to an oxidation of the adsorbed hydrocarbons by traces of oxygen in the adsorbent. Later study disproved this preliminary interpretation. Meanwhile several authors reported on the appearance of visible colorations and of an EPR spectrum, when anthracene and perylene were adsorbed from evacuated solutions on to a degassed silica-alumina catalyst (106-108). The EPR findings gave indication that adsorbed radicals were involved, similar to those found in strongly oxidizing acid solutions, where the anthracene or perylene cation radicals were expected to be formed (109). 

We have recorded the absorption bands and EPR spectrum which appear on contact of gaseous napthalene, anthracene, perylene, and tetracene under vacuum with the degassed surface of silica-alumina gels of different compositions 78, 78a, 110). A similar research with concordant results, has been recently reported by Hall (80a) for evacuated anthracene, perylene, pyrene, and 3,4-benzopyrene solutions in isooctane in which the adsorbent was immersed. 

Penta Mfg.. http //www.pentamfg.com] Recochem Robeco Ruger http //www.rugerchemicai.com] Sigma Sithean Spectrum Quality Prods. http //www.spectrumchemical.com] Stan Chem Int l. Ltd http //www.stanchem.co.uk, Sunoco http //www.sunocochem.com] Synasia Fine Chem. http //www.synasia.com Trade Name Synonyms 77.5 Napthalene (High Sulfur) [Koppers Ind. http //www.koppers.com]... 

The standard must be carefully chosen and it should ideally possess the following properties have a simple spectrum with very few bands be stable to heat and not absorb moisture be easily reduced to a particle size less than the incident radiation without lattice deformation be non-toxic, giving clear discs in a short time be readily available in the pure state. Some common standards used include calcium carbonate, sodium azide, napthalene and lead thiocyanate. 

Si <- Sq spectrum should exhibit the long-axis polarization of the intrinsic S -t- So Ag) transition. All of these band polarizations have been confirmed by obtaining absorption spectra of napthalene doped as an impurity into host crystals, where the napthalene orientations relative to the crystal axes are independently known. 

Another notable feature in the napthalene Sj Sq spectrum is the lack of progression formation—the absence of intense bands like 8(big)o (ag)o with n > 1. This indicates that large geometry changes do not occur along totally symmetry modes in the Si - Sq transitions. In this respect, napthalene is similar to aniline and contrasts with SO2. 

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