scholarly journals FTIR spectroscopy shows weak symmetric hydrogen bonding of the QB carbonyl groups in Rhodobacter sphaeroides R26 reaction centres

FEBS Letters ◽  
1995 ◽  
Vol 370 (1-2) ◽  
pp. 88-92 ◽  
Author(s):  
R. Brudler ◽  
H.J.M. de Groot ◽  
W.B.S. van Liemt ◽  
P. Gast ◽  
A.J. Hoff ◽  
...  
Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 833
Author(s):  
Edina Preklet ◽  
László Tolvaj ◽  
Eszter Visi-Rajczi ◽  
Tamás Hofmann

The goal of this research was the systematic study and comparison of the divided individual effects of UV light irradiation and water leaching during artificial weathering. Spruce (Picea abies Karst.) and Scots pine (Pinus sylvestris L.) samples were irradiated by ultraviolet (UV) light. Another sequence of samples was treated with the combination of UV irradiation and water leaching. The total extent of UV treatment was 20 days for both series of samples. Time relation of UV irradiation and water leaching was 2:1. The chemical changes were observed by FTIR spectroscopy. The difference spectrum was used for determination of the chemical changes. Degradation of lignin was greater for the leached samples than for the pure UV treated samples. Scots pine suffered greater lignin degradation than spruce, and produced higher absorption increase on the absorption region of unconjugated carbonyls. The unconjugated carbonyl groups were the most responsive chemical elements to leaching. Spruce was more susceptible to leaching of unconjugated carbonyl groups than Scots pine. Two absorption bands of unconjugated carbonyl groups at 1706 and 1764 cm−1 wavenumbers were produced by photodegradation. The absorption band at 1764 cm−1 was more sensitive to water leaching than the band at 1706 cm−1.


2005 ◽  
Vol 13 (4) ◽  
pp. 415-423
Author(s):  
Pan Wei ◽  
Yang Shenglin ◽  
Li Guang ◽  
Jiang Jianming

Blends of dodecylbenzene sulfonic acid-doped polyaniline (PANI-DBSA) with either polyacrylonitrile copolymer (PAN) or polystyrene (PS) were solution cast. The investigation focused on the interaction between the components, the morphology and the resulting electrical conductivity of blends. The results showed that with the same PANI-DBSA content the conductivity of PANI-DBSA/PAN was higher than that of PANI-DBSA/PS. PANI-DBSA was dispersed uniformly in the PAN matrix and its cluster size was rather smaller than in the PS matrix. This is attributed to hydrogen bonding between the carbonyl groups in PAN and the imine groups in PANI, which should lead to better compatibility between PANI-DBSA and PAN.


2007 ◽  
Vol 63 (3) ◽  
pp. o1173-o1175
Author(s):  
Stephanie M. Witko ◽  
Mark Davison ◽  
Hugh W. Thompson ◽  
Roger A. Lalancette

In the title crystal structure, C9H14O3·H2O, the water molecule accepts a hydrogen bond from the carboxyl group [O...O = 2.6004 (13) Å and O—H...O = 163°], while donating hydrogen bonds to the ketone [O...O = 2.8193 (14) Å and O—H...O = 178 (2)°] and the acid carbonyl groups [O...O = 2.8010 (14) Å and O—H...O = 174 (2)°]. This creates a network of hydrogen bonds confined within a continuous flat ribbon two molecules in width and extending in the [101] direction.


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