Absorption Spectra of Aromatic Hydrocarbons

Jones, R. N. The Ultra-violet absorption Spectra of Aromatic Hydrocarbons. 

Marchetti, A. P., Kearns, D. R. Investigation of singlet-triplet transitions by the phosphorescence excitation method. IV. The singlet-triplet absorption spectra of aromatic hydrocarbons. J. Am. Chem. Soc. 89, 768 (1967). 

This book is based on the reactions of thermal electrons with molecules. The ECD, negative-ion chemical ionization (NICI) mass spectrometry, and polaro-graphic reduction in aprotic solvents methods are used to determine the kinetic and thermodynamic parameters of these reactions. The chromatograph gives a small pure sample of the molecule. The temperature dependence of the response of the ECD and NIMS is measured to determine fundamental properties. The ECD measurements are verified and extended by correlations with half-wave reduction potentials in aprotic solvents, absorption spectra of aromatic hydrocarbons and donor acceptor complexes, electronegativities, and simple molecular orbital theory. 

TABLE 6.5 Absorption Spectra of Aromatic Hydrocarbons—Absorption Maxima of Highest Wavelength... 

Herington, E. F. G. and Kynaston, W. (1952) The effect of solvent on the ultra-violet absorption spectra of aromatic hydrocarbons with special reference to the mechanism of salting-out. Part II aqueous salt solutions. J. Chem. Soc. (Lond.), 3143-9. 

Hochstrasser RM, Lower SK (1964) Polarized tanission and triplet-triplet absorption spectra of aromatic hydrocarbons in btaizophtatone crystals. J Chem Phys 40 1041-1046... 

Fig. B3.1. Illustration of the vibrational bands in the absorption and fluorescence spectra of aromatic hydrocarbons. Broadening of the bands will be explained in Section 3.5.1.

Absorption and fluorescence spectra of aromatic hydrocarbons are not greatly affected by change of solvent, except for small solvent shifts. At low temperatures the vibrational structure of the bands sharpens up, and some peculiar solvent effects have been noted. When frozen in solution of normal paraffins coronene shows doubling of some of its vibrational bands, and the separation of the components varies with the number of carbon atoms in the solvent molecule chain. The most probable cause is some size-relationship factor between solvent and solute molecules (7). 

Absorption Spectra of Alternate Hydrocarbons and Aromatic Nitrogen Compounds and Weights of Component Configurations by the Cl Procedure"... 

Typical U V spectra of aromatic hydrocarbons are shown in Figure 2.7. They contain absorption bands that fall into three categories according to their intensity ... 

Figure 2.7. Absorption spectra of naphthalene, anthracene, and tetracene as typical examples of the UV spectra of aromatic hydrocarbons (by permission from DMS UV-Atlas, 1966-71).

It has long been realized that excellent correlations exist between 1/2 or and molecular orbital parameters [172,178-181]. Correlations between voltammetric data and experimental observables such as ionization potentials (IP) [172,178,182,183], charge-transfer transition energies [172], and positions of p-bands in ultraviolet (UV) absorption spectra of the hydrocarbons [4,172] have been reported as well. The basis and limitations of such correlations have been examined critically [147,175,184]. For alkyl aromatic hydrocarbons (AAHs), the slope, a, of the correlation line [Eq. (56)], where E° is the standard potential for the reversible one-electron oxidation, is close to unity and has been used to suggest that in MeCN the solvation energies of the hydrocarbon radical cations are constant throughout the series [175]. 

The ultraviolet spectra of aromatic hydrocarbons are characterized by three sets of bands that originate from sr— sT transitions. For exantpic, benzene has a strong absorption peak at 184 nm (s a, = 60,000) a weaker band, called the E, band, at 204 nm (e ,a, = 7900) and a still weaker peak, termed the B band, at 256 (Sniax = 200). The long-wavelength bands of benzene vapor, 1,2,4,5-tetrazine (see Figure 14-la), and many other aromatics contain a series of sharp peaks due to the superposition of vibrational transitions on the basic electronic transitions. As shown in Figure 14-1, solvents tend to reduce (or sometimes eliminate) this fine structure as do certain types of substitution. 

This exercise provides the opportunity of examining the absorption spectra of typical aromatic hydrocarbons and of investigating the possibility of analysing mixtures of hydrocarbons by ultraviolet spectrophotometry. 

Craig, D. P., Ross, I, G. The triplet-triplet absorption spectra of some aromatic hydrocarbons and related substances. J. Chem. Soc. 1954, 1589 (1954). 

Figure 6.11 The rate of energy transfer et asa function of overlap integral between the emission spectra of the donorand the absorption spectra of the acceptor and the rate constant for energy transfer, In each case donor (dotted line) is benzene and acceptor (solid Vine") are aromatic hydrocarbons of different singlet state energy E . The energy scale is expressed in kcc.l mol-...

An optoelectronic image device has been used as an HPLC detector to obtain UV absorption spectra of shale oil aromatic hydrocarbons separated isocratically (10). Since isocratic separations maintain a constant mobile phase composition, the... 

The Triplet-Triplet Absorption Spectra of Some Aromatic Hydrocarbons and Related Substances. 

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