Anthochlor Pigments. XIII. The Ultraviolet Absorption Spectra of Phenolic Plant Pigments. Polyhydroxyaurones

1956 ◽  
Vol 78 (4) ◽  
pp. 832-837 ◽  
Author(s):  
T. A. Geissman ◽  
J. B. Harborne



2013 ◽  
Vol 779 (1) ◽  
pp. 40 ◽  
Author(s):  
Yu-Jong Wu ◽  
Hui-Fen Chen ◽  
Shiang-Jiun Chuang ◽  
Tzu-Ping Huang


1950 ◽  
Vol 187 (1) ◽  
pp. 299-312
Author(s):  
R.L. Sinsheimer ◽  
J.F. Scott ◽  
J.R. Loofbourow


1956 ◽  
Vol 21 (9) ◽  
pp. 993-996 ◽  
Author(s):  
HERBERT E. UNGNADE ◽  
ROBERT A. SMILEY




1959 ◽  
Vol 37 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Eugene Lieber ◽  
J. Ramachandran ◽  
C. N. R. Rao ◽  
C. N. Pillai

The ultraviolet absorption spectra of 5-(substituted)amino-1,2,3,4-thiatriazoles and the corresponding isomeric 1-substituted-tetrazoline-5-thiones have been studied. The spectra and the dipole moments of the 5-(substituted)amino-1,2,3,4-thiatriazoles eliminate the possibility of meso-ionic structures for these compounds. The dipole moments of 5-amino-, 5-methylamino-, and 5-dimethylamino-1,2,3,4-thiatriazole were all high but approximately of the same value (5.77 to 5.84 D). This suggests that the amino thiatriazoles are best represented by conventional covalent structures with significant ionic resonance contributions. The thiatriazole ring system exhibits a characteristic absorption maximum at 250–255 mμ and an electron-withdrawing effect approximately equal to the tetrazolyl ring system. The tetrazolinethionolyl ring system is similarly electron-withdrawing. The relative acidities of the 1-substituted-tetrazoline-5-thiones and the 5-alkylmercaptotetrazoles have also been studied and the results support the observations made on the basis of their ultraviolet absorption spectra.



1962 ◽  
Vol 8 (1-6) ◽  
pp. 257-275 ◽  
Author(s):  
Haruo Hosoya ◽  
Jiro Tanaka ◽  
Saburo Nagakura




1965 ◽  
Vol 2 (3) ◽  
pp. 291-297 ◽  
Author(s):  
Nelson J. Leonard ◽  
Kermit L. Carraway ◽  
John P. Helgeson


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