Transient Intermediates in the Laser Flash Photolysis of Ketoprofen in Aqueous Solutions:  Unusual Photochemistry for the Benzophenone Chromophore

1997 ◽  
Vol 119 (45) ◽  
pp. 11066-11070 ◽  
Author(s):  
L. J. Martínez ◽  
J. C. Scaiano
Keyword(s):  
Aqueous Solutions ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Transient Intermediates

Intermediates formed by laser flash photolysis of [PtCl6]2– in aqueous solutions

2005 ◽  
Vol 4 (11) ◽  
pp. 897 ◽  
Author(s):  
Irene V. Znakovskaya ◽  
Yulia A. Sosedova ◽  
Evgeni M. Glebov ◽  
Vjacheslav P. Grivin ◽  
Victor F. Plyusnin
Keyword(s):  
Aqueous Solutions ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

Photolysis of aqueous solutions of aniline-2,5-disulfonic acid: steady state and laser flash photolysis studies

2002 ◽  
Vol 1 (7) ◽  
pp. 514-519 ◽  
Author(s):  
Jaouad Elgouch ◽  
Carole Catastini ◽  
Bernadette Lavedrine ◽  
Ghislain Guyot ◽  
Mohamed Sarakha
Keyword(s):  
Steady State ◽  
Aqueous Solutions ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Disulfonic Acid

Reaction of the tamoxifen cation and the bis-(4-methoxyphenyl)methyl cation in aqueous solutions containing 2'-deoxyguanosine

2002 ◽  
Vol 80 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Robert A McClelland ◽  
Cristina Sanchez ◽  
Effiette Sauer ◽  
Sinisa Vukovic
Keyword(s):  
Aqueous Solutions ◽  
Rate Constant ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
High Rate ◽  
Group A ◽  
Stable Product ◽  
High Concentrations ◽  
Conjugate Base

The competition between 2'-deoxyguanosine (dG) and water has been quantitatively evaluated for the allylic carbocation derived from tamoxifen and for the stabilized diarylmethyl cation (bis-(4-methoxyphenyl)methyl). Both systems were examined by the competition kinetics method, in which the products were quantitatively analyzed after the SN1 solvolysis of the corresponding acetate esters in aqueous solutions containing the nucleoside. The principal product of the reaction of both cations with dG is the adduct at the NH2 group, a characteristic of delocalized carbocations. The tamoxifen cation was also examined by laser flash photolysis, with absolute rate constants for the reaction with dG and water being obtained and converted into rate constant ratios. The principal result of this study is that there is a three orders of magnitude difference in the reactivity of these cations towards the neutral form of dG and its conjugate base. Under acidic conditions where the reaction occurs with neutral dG, the guanine–water selectivity is low. Even at relatively high concentrations of dG, the majority of the product is alcohol derived from the water reaction. At pH 10 to 11, in contrast, dG is present as the anion and this is highly competitive. Yields of adduct as high as 90% can be attained. A consequence of the large difference in reactivities is that at neutral pH the majority of the reaction of the cation with dG is actually occurring via the small amount of conjugate base present. A further feature of the results is that the NH2 adduct is the predominant stable product from the anion. To explain the high rate constant for the reaction forming this product, a mechanism is proposed whereby one of the protons of the NH2 group is transferred to N1 as the N2-cation bond is forming.Key words: guanine, DNA adduct, carbocation, tamoxifen.

Investigation of fulvic acid photochemistry in aqueous solutions by stationary and laser flash photolysis techniques

2014 ◽  
Vol 48 (3) ◽  
pp. 197-201 ◽  
Author(s):  
M. P. Makunina ◽  
I. P. Pozdnyakov ◽  
V. P. Grivin ◽  
V. F. Plyusnin
Keyword(s):  
Aqueous Solutions ◽  
Fulvic Acid ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash

Laser flash photolysis of fullerols of C60 and of C70 in aqueous solutions

1998 ◽  
Vol 41 (3) ◽  
pp. 259-265 ◽  
Author(s):  
Changyuan Lu ◽  
Side Yao ◽  
Wenfeng Wang ◽  
Yongpeng Tong ◽  
Weizhen Lin ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash
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