Ultraviolet and Visible Absorption Spectra

Ultraviolet and Visible Absorption Spectra Although many studies have been performed on human erythrocuprein, no comprehensive and detailed spectrum of this metalloprotein in the visible and ultraviolet region has yet been reported. Carrico and Deutsch (66, 68, 69) measured the absorption spectra manually and, due to this technique, a fine structure was not observed. Keele, McCord and Fridovich (82) published a comparison of the UV absorption spectra of human and bovine erythrocuprein in the wavelength region 240 to 310 nm. In Fig. 6a distinct fine structure can be seen in the absorption spectrum of human erythrocuprein. Absorption bands appear at 254, 260, 266, 326 nm and shoulders at 270, 282 and 289 nm. 

It is interesting to note the unusual diminished absorption in the 280 nm region ( 265 = 17,000). This was attributed at the low content of aromatic amino-acid residues, especially typosine and tryptophan. The absorption in the visible region was extremely low. Apart from the broad absorption band at 675 20 nm ( 675=275), a shoulder can be observed at 440 nm (Fig. 7). According to the definition given by Malkin and Malmstrom (3), erythrocuprein is classified as a non-blue copper protein. 

6 und 7. Absorption spectrum of human erythrocuprein. The protein was isolated using the method given in Ref. (74). Recording was carried out with a Unicam SP 1800. 

Low-temperature absorption studies promised valuable information in the visible region (Fig. 9). As expected, the absorption of erythrocuprein at 680 nm was increased by a factor of approximately 5 and the shoulder at 430 nm was more distinct than at room temperature. The absorption band at 680 nm and the shoulder at 430 nm cannot be precisely assigned at present, though they are presumably due to either a pure d-+d transition or a charge transfer band, or a mixture of both. Furthermore, the possibility that the 680 nm band represents more than one d- -d transition was not excluded (73). This thought gained substantial support from CD and especially MCD data. 

Optical Rotatory Dispersion (ORD) and Magnetic Optical Rotatory Dispersion (MORD) 

When a valence s electron of one atom moves into the same orbital as a valence s electron of another atom, the two atoms may form either a bond or an antibond, depending on whether the resultant bond energy is stable. The antibond is also called an excited state. The bond, which is stable, is designated as a cj bond the antibond, which is not stale, is designated as a ct bond. If a valence s electron of one atom shares its orbital with a valence p electron of another atom or if a valence p electron of an atom shares its orbital with another valence p electron of another atom, then we have either a n bond or a Jt antibond, which again depends on whether the resultant bond energy is stable. In some atoms, such as N, O, and S, or 

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A. Electronic (Ultraviolet and Visible) Absorption Spectra The electronic absorption spectra of heterocyclic molecules have their origins in the transitions of electrons between different molecular orbitals. In general, the more these orbitals are spread out in space, the closer together are their energy levels and the longer the wavelengths... 

Chase, A. M., and Brigham, E. H. (1951). The ultraviolet and visible absorption spectra of Cypridina luciferin solutions. J. Biol. Chem. 190 529-536. 

W.A. Schroeder et al, Ultraviolet and Visible Absorption Spectra in Ethyl Alcohol. 

Salfeld JC (1972) Ultraviolet and visible absorption spectra of humic systems. In Humic Substances (eds Povoledo D, Golterman HL), Center for Agriculture Publications and Documentation, Wageningen, The Netherlands, p. 269-280... 

CA 49,7391(1955)(Explosive combustion of hydrocarbons — comparative investigation and study of continuous spectra) llJH.M.Hershen-son, "Ultraviolet and Visible Absorption Spectra , Index for 25 years — 1930 to 1954, Academic Press, NY(1956) I2)A.Gillam ... 

B-61MI21400 H. M. Hershenson in Ultraviolet and Visible Absorption Spectra, Indexes for... 

CA 43, 8l38-9( 1949)(Chromatographic investigation of proplnts using various stabilizers, among them Centr 2) 5)W. A.Schroeder er al, AnalChem 23, 1740-7(1951) CA 46, 5434(1952) (Detn of ultraviolet and visible absorption spectra of several stabilizers, among them Centr 2, in ethanol) 6)F.Pristera, AnalChem 25, 844... 

The ultraviolet and visible absorption spectra of single atoms consist of a number of sharp lines, which correspond to the promotion of an electron from one orbital to another. Each atomic orbital has a well-defined energy, and there-... 

Support for these considerations is given by Papazian (27), who studied the ultraviolet and visible absorption spectra of HN3, photochemically decomposed at —200° C. He postulated the primary production of NH radicals, followed by reactions in the matrix to produce diaminohydrazine (HN=N—N=NH), triazene (H2N—N=N—H), and the radical H—H—N he ascribed the blue color and paramagnetism of the solid to this radical. 

Kum-Tattbt> identified meperidine by preparing the ammonium reineckate derivative and determining several physical properties of the reineckate including its ultraviolet and visible absorption spectra in ethanol. Basu and Dutta57 quantitatively determined meperidine by dissolving the ammonium reineckate in acetone and measuring the absorbance at 525 m/i. 

The product, a-hydroxymuconic semialdehyde, was isolated and characterized from a large scale incubation. Its elemental analysis, infrared, ultraviolet and visible absorption spectra, and its rapid decomposition to pyruvate by extracts of Pseudomonas aeruginosa T1 (JO) are all consistent with this structure. 

H. M. Hershenson, Ultraviolet and Visible Absorption Spectra, Academic Press, New York (Index for 1930-1954), 1956 (Index for 1955-1959), 1961 DMS, UV Atlas of Organic Compounds, Vols. 1-4, Verlag Chemie,Weinheim Butterworths, London (1968)... 

Infrared spectra are directly involved with the vibrations of the atoms or groups of atoms in a molecule (as distinguished, e.g., from rotations of the whole molecule, or from electronic motions characteristic of ultraviolet and visible absorption spectra). When we examine infrared absorption characteristics we are studying group vibrations. As a first approach to the study of these vibrations let us consider the vibrations of small molecules and the common ways of looking at such systems. 

Fig. 1 Ultraviolet and visible absorption spectra of PPV prepared by two different precursor routes by heating to 300°C for one hour. The absorption edge of the material prepared from a tetrahydrophenium salt precursor (solid line) appears nearly 0.1 eV lower than that prepared from a sulphonium salt precursor (broken line), and shows more pronounced phonon structure.

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