Benzene derivatives ultraviolet spectra

It should however be borne in mind that positions 9 and 10 in anthracene are not typically aromatic. They are manifested ]>y a higher reactivity than positions Ur and 0 as established by MO calculation [50]. In addition 9-nitroanthracene shows a non-planar structure with the nitro group out of plane [51] as pointed out by Cerfontain and Telder [48]. This is very similar to the position of the nitro group in o-dinitrobenzene and all derivatives of benzene with two ortho nitro groups. It is well known that the nitro groups in o-dinitrobenzene are not planar and there is no conjugation of double bonds in this compound. Tlie fact is also reflected in ultraviolet-absorption spectrum of o-dinitrobenzene which deviates from those of m- and p-dinitrobenzenes (Vol. I, p. 169, Table 20). 

Hgure 7 Influence of the modulation amplitude a [8] on the shape of a second-order derivative spectrum [19]. The example was determined by means of an aqueous sample containing approx. Imgl of each benzene, toluene, p-xylene. (Reprinted with permission from Vogt F, Tacke M, Jakusch M, and Mizaikoff B (2000) An ultraviolet spectroscopic method for monitoring aromatic hydrocarbons dissolved in water. Analytica Chimica Acta 422 187-198 Elsevier cf. Erratum (2001) Analytica Chimica Acta 431 167.)... 

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