Neutral hypoxanthine in aqueous solution: quantum chemical and Monte-Carlo studies

2004 ◽  
Vol 711 (1-3) ◽  
pp. 83-94 ◽  
Author(s):  
María Luisa San Román-Zimbrón ◽  
María Eugenia Costas ◽  
Rodolfo Acevedo-Chávez
Keyword(s):  
Aqueous Solution ◽  
Monte Carlo ◽  
Quantum Chemical ◽  
Monte Carlo Studies

Monte Carlo studies of aqueous solution of nitrogen using different potential energy surfaces

1986 ◽  
Vol 58 (1) ◽  
pp. 65-83 ◽  
Author(s):  
E.S. Fois ◽  
A. Gamba ◽  
G. Morosi ◽  
P. Demontis ◽  
G.B. Suffritti
Keyword(s):  
Aqueous Solution ◽  
Monte Carlo ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Monte Carlo Studies ◽  
Energy Surfaces

Monte Carlo studies on the structure of a dilute aqueous solution of methane

1978 ◽  
Vol 100 (18) ◽  
pp. 5705-5712 ◽  
Author(s):  
S. Swaminathan ◽  
S. W. Harrison ◽  
David L. Beveridge
Keyword(s):  
Aqueous Solution ◽  
Monte Carlo ◽  
Monte Carlo Studies ◽  
Dilute Aqueous Solution

Monte Carlo studies of the structure of NaCl aqueous solution at three different concentrations

1985 ◽  
Vol 22 (1-5) ◽  
pp. 23-28
Author(s):  
Jumras P. Limtrakul ◽  
Michael M. Probst ◽  
Bernd M. Rode
Keyword(s):  
Aqueous Solution ◽  
Monte Carlo ◽  
Monte Carlo Studies

Monte Carlo studies of a dilute aqueous solution of benzene

1984 ◽  
Vol 106 (15) ◽  
pp. 4096-4102 ◽  
Author(s):  
Per Linse ◽  
G. Karlstroem ◽  
B. Joensson
Keyword(s):  
Aqueous Solution ◽  
Monte Carlo ◽  
Monte Carlo Studies ◽  
Dilute Aqueous Solution

scholarly journals Monte Carlo studies of pion distributions from heavy ion collisions

1983 ◽  
Vol 27 (2) ◽  
pp. 606-627 ◽  
Author(s):  
Hafez M. A. Radi ◽  
John O. Rasmussen ◽  
Kenneth A. Frankel ◽  
John P. Sullivan ◽  
H. C. Song
Keyword(s):  
Monte Carlo ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Ion Collisions ◽  
Monte Carlo Studies

scholarly journals Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 497
Author(s):  
Ewa D. Raczyńska
Keyword(s):  
Aqueous Solution ◽  
Quantum Chemical ◽  
Biologically Active ◽  
Deprotonation Reaction ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Scanty Information ◽  
Derivatives Of ◽  
Common Anion ◽  
Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

Reverse Monte Carlo studies of nanoporous carbon from TiC

2005 ◽  
Vol 17 (23) ◽  
pp. 3509-3524 ◽  
Author(s):  
Per Zetterström ◽  
Sigita Urbonaite ◽  
Fredrik Lindberg ◽  
Robert G Delaplane ◽  
Jaan Leis ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Nanoporous Carbon ◽  
Reverse Monte Carlo ◽  
Monte Carlo Studies
Sign in / Sign up

Export Citation Format

Share Document