H-chromophores

Dubai H-R and Quack M 1980 Spectral bandshape and intensity of the C-H chromophore in the... 

The study indicated that the ground state of the molecule should be regarded as a resonance hybrid of (1) and (118) and that the basic chromogen is the H- chromophore... 

Schafer LV, Groenhof G, Boggio-Pasqua M, Robb MA, GmbmuUer H. Chromophore protonation state controls photoswitching of the fluoroprotein asFP595. PLoS Comput Biol. 2008 4 el000034. 

Wagner, D., Fairchild, C.D., Kuhn, R.M., and Quail, P.H., Chromophore-bearing N-terminal domains of phytochromes A and B determine their photosensory specificity and differential Hght lability, Proc. Natl Acad. Sci USA, 93,4011, 1996. 

Dubai H-R and Quack M 1984 Tridiagonal Fermi resonance structure in the IR spectrum of the excited CH chromophore in CFgH J. Chem. Phys. 81 3779-91... 

Segall J, Zare R N, Dubai H R, Lewerenz M and Quack M 1987 Tridiagonal Fermi resonance structure in the vibrational spectrum of the CM chromophore in CHFg. II. Visible spectra J. Chem. Phys. 86 634-46... 

Dubai H-R, Ha T-K, Lewerenz M and Quack M 1989 Vibrational spectrum, dipole moment function, and potential energy surface of the CH chromophore In CHXg molecules J. Chem. Phys. 91 6698-713... 

Nakahara H and Fukuda K 1983 Orientation of chromophores in monolayers and multilayers of azobenzene derivatives with long alkyl chains J. Colloid Interface Sol. 93 530-9... 

Deisenhofer J, Epp O, Miki K, Huber R and Michei H 1984 X-ray structure anaiysis of a membrane-protein compiex eiectron density map at 3 A resoiution and a modei of the chromophores of the photosynthetic reaction center from Rhode pseudomonas viridis J. Mol. Biol. 180 385-98... 

A mild procedure which does not involve strong adds, has to be used in the synthesis of pure isomers of unsymmetrically substituted porphyrins from dipyrromethanes. The best procedure having been applied, e.g. in unequivocal syntheses of uroporphyrins II, III, and IV (see p. 251f.), is the condensation of 5,5 -diformyldipyrromethanes with 5,5 -unsubstituted dipyrromethanes in a very dilute solution of hydriodic add in acetic acid (A.H. Jackson, 1973). The electron-withdrawing formyl groups disfavor protonation of the pyrrole and therefore isomerization. The porphodimethene that is formed during short reaction times isomerizes only very slowly, since the pyrrole units are part of a dipyrromethene chromophore (see below). Furthermore, it can be oxidized immediately after its synthesis to give stable porphyrins. 

FIGURE 10.22 The reaction cycle of bacteriorhodopsin. The intermediate states are indicated by letters, with subscripts to indicate the absorption maxima of the states. Also indicated for each state is the configuration of the retinal chromophore (all-tram or 13-cas) and the protonation state of the Schiff base (C=N or C=N H). 

The infrared spectrum of 2-hydroxythiophene was originally interpreted as showing both vOH and vC=0 peaks indicating that it exists as a mixture of the hydroxy form 39 (R — H) and at least one of the 0X0 forms, 40 and/or 41. The ultraviolet spectrum of 2-hydroxythiophene is different from that of the corresponding methyl ether (39, R = Me) suggesting the presence of the chromophore contained in structure 40. The facts that this compound gives a positive... 

Rosenow, M. A., Huffman, H. A., Phail, M. E., and Wachter, R. M. (2004). The crystal structure of the Y66L variant of green fluorescent protein supports a cyclization-oxidation-dehydration mechanism for chromophore maturation. Biochemistry 43 4464 1472. 

Takahashi, H., and Isobe, M. (1993). Symplectoteuthis bioluminescence. (1). Structure and binding form of chromophore in photoprotein of a luminous squid. Bioorg. Med. Chem. Lett. 3 2647-2652. 

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