Ionization potential and hyperfine splitting constant of the molecular fluorine radical anion. An ab initio study

1987 ◽  
Vol 91 (7) ◽  
pp. 1703-1704 ◽  
Author(s):  
. Nguyen Minh Tho ◽  
Tae Kyu. Ha
Keyword(s):  
Ab Initio ◽  
Ionization Potential ◽  
Hyperfine Splitting ◽  
Radical Anion ◽  
Ab Initio Study ◽  
Hyperfine Splitting Constant ◽  
Splitting Constant

scholarly journals What properties of non-electrolyte solutions does a DNA molecule feel?

2021 ◽  
Vol 13 (2) ◽  
pp. 129-136
Author(s):  
George G. Malenkov ◽  
Keyword(s):  
Relative Humidity ◽  
Ethylene Glycol ◽  
Water Activity ◽  
Hyperfine Splitting ◽  
Solvent Polarity ◽  
Electrolyte Solutions ◽  
Water Solutions ◽  
Hyperfine Splitting Constant ◽  
Splitting Constant ◽  
In The Beginning

As early as in 1953 it was reported that at low relative humidity of the atmosphere (about 70 %) DNA films were in A-form, while at higher humidity (more than 80%) they were in B-form. Relative humidity of the atmosphere corresponds to the water activity in the system. It was found in the beginning of the 70th that DNA transfers to the A-form when non-electrolytes, such as monoatomic alcohols, dioxane, tetrahydrofurane were added to water. It was reasonable to suppose that B to A transition of DNA occurs in the non-electrolyte solutions at the same values af water activity as in the moist atmosphere. This prediction was borne out. But in water solutions of very polar non-electrolytes such as methanol and ethylene glycol B to A DNA does not occur even at very low water activity values. It was supposed that A form of DNA can arise only in the medium with sufficiently low polarity. We used hyperfine splitting constant (A) of a nitroxide spin label determined from the EPR spectra as a measure of the liquid solvent polarity. It was found that DNA transition into B form occurs when A reached a certain value. Polarity of methanol and ethylene glycol is much higher than that of the solutions in which B to A DNA transition takes place. This transition also occurs in water solutions of trifluoroethanol. But in these solutions the transition takes place at hyperfine splitting values, which are much greater than in other non-electrolyte solutions. Water activity in the zone of B-A DNA transition in trifluoroethanol solutions does not correspond water activity which was calculated for other nob-electrolyte solutions in which B-A transition is observed.

First Synthesis of C-Phenyl N-tert-Butyl [15N]nitrone (PBN-15N) for the EPR Spin Trapping Methodology

1996 ◽  
Vol 51 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Yong-Kang Zhang
Keyword(s):  
Hyperfine Splitting ◽  
Spin Trap ◽  
Spin Trapping ◽  
Paramagnetic Resonance ◽  
Tert Butyl ◽  
Hyperfine Splitting Constant ◽  
Percent Increase ◽  
Splitting Constant ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic

As compared to normal PBN, about fifty percent increase of electron paramagnetic resonance (EPR) spin trapping sensitivity has been gained by using a new 100% 15N-enriched spin trap, C-phenyl N-tert-butyl[15N]nitrone (PBN-15N). PBN-15N has been prepared by a convenient four-step route using ammonium-15N chloride as the starting material. This synthetic method produces 2-methyl-2-[15N]nitropropane which is useful for the synthesis of many other PBN-15N type spin traps for the purpose of increasing spin trapping sensitivity. EPR spin trapping with PBN-15N in benzene and in phosphate buffer has been investigated. The 15N hyperfine splitting constant (15N-hfsc) is larger than 14N-hfsc by 40%. The larger 15N-hfsc gives more opportunity to identify different radical addends within the same system.

Structure of thiocyanate dimer radical anion: An ab initio study

2005 ◽  
Vol 723 (1-3) ◽  
pp. 235-239 ◽  
Author(s):  
Ravi Joshi ◽  
Tapan K. Ghanty ◽  
Tulsi Mukherjee
Keyword(s):  
Ab Initio ◽  
Radical Anion ◽  
Ab Initio Study

Is acetylene radical anion with a trans–bent form observed in matrix experiment? An ab initio study

1996 ◽  
Vol 105 (15) ◽  
pp. 6385-6387 ◽  
Author(s):  
Tae‐Kyu Ha ◽  
Hans Ulrich Suter ◽  
Minh Tho Nguyen
Keyword(s):  
Ab Initio ◽  
Radical Anion ◽  
Ab Initio Study
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