Hydrogen bond effect on the photophysical properties of 2-ureido-4[1H]-pyrimidinone quadruple hydrogen bonded systems

RSC Advances ◽  
2015 ◽  
Vol 5 (46) ◽  
pp. 36279-36287 ◽  
Author(s):  
Jun-Sheng Chen ◽  
Feng-Jiao Zhao ◽  
Yang Yang ◽  
Tian-Shu Chu
Keyword(s):  
Hydrogen Bond ◽  
Photophysical Properties ◽  
Hydrogen Bonded Systems ◽  
Bond Effect ◽  
Hydrogen Bonded

Two different hydrogen bond effects on the photophysical properties of UPy systems in different solutions have been studied.

scholarly journals How water-mediated hydrogen bonds affect chlorophyll a/b selectivity in Water-Soluble Chlorophyll Protein

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alessandro Agostini ◽  
Elena Meneghin ◽  
Lucas Gewehr ◽  
Danilo Pedron ◽  
Daniel M. Palm ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Binding Sites ◽  
Photophysical Properties ◽  
Water Soluble ◽  
Variable Degree ◽  
Formyl Group ◽  
Hydrogen Bond Networks ◽  
Conformational Freedom ◽  
Chlorophyll Protein ◽  
Hydrogen Bonded

AbstractThe Water-Soluble Chlorophyll Protein (WSCP) of Brassicaceae is a remarkably stable tetrapyrrole-binding protein that, by virtue of its simple design, is an exceptional model to investigate the interactions taking place between pigments and their protein scaffold and how they affect the photophysical properties and the functionality of the complexes. We investigated variants of WSCP from Lepidium virginicum (Lv) and Brassica oleracea (Bo), reconstituted with Chlorophyll (Chl) b, to determine the mechanisms by which the different Chl binding sites control their Chl a/b specificities. A combined Raman and crystallographic investigation has been employed, aimed to characterize in detail the hydrogen-bond network involving the formyl group of Chl b. The study revealed a variable degree of conformational freedom of the hydrogen bond networks among the WSCP variants, and an unexpected mixed presence of hydrogen-bonded and not hydrogen-bonded Chls b in the case of the L91P mutant of Lv WSCP. These findings helped to refine the description of the mechanisms underlying the different Chl a/b specificities of WSCP versions, highlighting the importance of the structural rigidity of the Chl binding site in the vicinity of the Chl b formyl group in granting a strong selectivity to binding sites.

Proton transfer in hydrogen bonded systems

1960 ◽  
Vol 257 (1288) ◽  
pp. 98-108 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Absorption Band ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Direct Result ◽  
Isotopic Substitution ◽  
Association Energy ◽  
Hydrogen Bonded Systems ◽  
Hydrogen Bonded

Evidence is presented that proton transfer occurs in certain special types of hydrogen bond and that as a direct result the association energy is increased. It is probable that this effect is also responsible for a t least a part of the broadening of the v XH absorption band. In support of this, a number of com pounds are described in which the hydrogen bonds are weakened by isotopic substitution. The implications of these findings are discussed.

Properties of strong hydrogen-bonded systems. II.Ab initioSCF-MO study of the hydrogen bond between nitric acid and ammonia

1980 ◽  
Vol 1 (4) ◽  
pp. 417-419 ◽  
Author(s):  
Z. Latajka ◽  
M. M. Szcz�?niak ◽  
H. Ratajczak ◽  
W. J. Orville-Thomas
Keyword(s):  
Hydrogen Bond ◽  
Nitric Acid ◽  
Hydrogen Bonded Systems ◽  
Hydrogen Bonded

Application of photoelectron spectroscopy to intramolecularly hydrogen-bonded systems. Part II. On the n–π* blue shift of carbonyl-containing molecules

1976 ◽  
Vol 54 (20) ◽  
pp. 3203-3205 ◽  
Author(s):  
R. S. Brown
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
Photoelectron Spectroscopy ◽  
Blue Shift ◽  
Photoelectron Spectra ◽  
Ultraviolet Spectra ◽  
Hydrogen Bonded Systems ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonded

The photoelectron spectra of 2-hydroxycyclohexanone and 2-methoxycyclohexanone, show that the ionization assigned to removal of the carbonyl n-electron is 0.6 eV higher in the former, presumably due to the intramolecular hydrogen bond. The ultraviolet spectra of these molecules also exhibit a marked blue shift of the n → π* transition in the former of roughly 0.5 eV. A discussion of the observations includes consideration of the effect of the intramolecular hydrogen bond on the ground and excited or ion state.

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