scholarly journals A Computational Study of 2-(chloromethyl)oxirane Ring Opening by Bromide and Acetate Anions Considering Electrophilic Activation with Cations of Alkali Metals

2019 ◽  
Vol 92 (3) ◽  
pp. 357-367 ◽  
Author(s):  
Kseniia Yutilova ◽  
Yuliia Bespal’ko ◽  
Elena Shved
Keyword(s):  
Alkali Metal ◽  
Metal Cation ◽  
Ring Opening ◽  
Density Functional ◽  
Alkali Metals ◽  
Computational Study ◽  
Alkali Metal Cation ◽  
Transition States ◽  
Activation Parameters ◽  
Electrophilic Activation

Ring opening of 2-(chloromethyl)oxirane via the nucleophilic substitution with bromide and acetate anions was investigated using density functional theory (DFT) calculations. It was shown that the geometry of the transition states and the activation parameters of the reactions correspond to those of SN2-like mechanism. The nature of localized transition states was analyzed using More O’Ferrall – Jencks plots. The quantum chemical simulations of the potential energy surface for the ring-opening reaction of oxirane by nucleophiles confirmed the theoretical assumptions about the favored path of interactions, which is a backside α-attack of nucleophile. The effect of alkali metal cation (Li+, Na+, K+) on that path was estimated. It was found that the electrophilic activation with alkali metal cation is more pronounced in the reaction of 2-(chloromethyl)oxirane with dissociated ions, than with ionic pairs.

Hydrogen bonding in alkali metal cation-bound i-motif-like dimers of 1-methyl cytosine: an IRMPD spectroscopic and computational study

2019 ◽  
Vol 21 (21) ◽  
pp. 11103-11110 ◽  
Author(s):  
Ruodi Cheng ◽  
Estelle Loire ◽  
Travis D. Fridgen
Keyword(s):  
Hydrogen Bonding ◽  
Alkali Metal ◽  
Gas Phase ◽  
Vibrational Spectroscopy ◽  
Computational Methods ◽  
Metal Cation ◽  
Computational Study ◽  
Alkali Metal Cation ◽  
Alkali Metal Cations ◽  
Methyl Cytosine

The structures of alkali metal cation bound 1-methylcytosine (1-mCyt) dimers were explored using vibrational spectroscopy in the gas phase and by computational methods. A transition from structures absent of hydrogen bonding for the light alkali metal cations to those with predominant hydrogen bonding for the larger cations was observed.

scholarly journals Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroya Suno ◽  
Masahiko Machida ◽  
Terumi Dohi ◽  
Yoshihito Ohmura
Keyword(s):  
Alkali Metal ◽  
Metal Cation ◽  
Quantum Chemical ◽  
Alkali Metals ◽  
Alkali Metal Cation ◽  
Usnic Acid ◽  
Physiological Role ◽  
Preference Order ◽  
Chemical Calculation ◽  
Alkali Cations

AbstractWe evaluate stability of cesium (Cs) and other alkali-metal cation complexes of lichen metabolites in both gas and aqueous phases to discuss why lichens can retain radioactive Cs in the thalli over several years. We focus on oxalic acid, (+)-usnic acid, atranorin, lecanoric acid, and protocetraric acid, which are common metabolite substances in various lichens including, e.g., Flavoparmelia caperata and Parmotrema tinctorum retaining Cs in Fukushima, Japan. By performing quantum chemical calculations, their gas-phase complexation energies and aqueous-solution complexation free energies with alkali-metal cations are computed for their neutral and deprotonated cases. Consequently, all the molecules are found to energetically favor cation complexations and the preference order is Li$$^+>$$ + > Na$$^+>$$ + > K$$^+>$$ + > Rb$$^+>$$ + > Cs$$^+$$ + for all conditions, indicating no specific Cs selectivity but strong binding with all alkali cations. Comparing complexation stabilities among these metabolites, lecanoric and protocetraric acids seen in medullary layer are found to keep higher affinity in their neutral case, while (+)-usnic acid and atranorin in upper cortex exhibit rather strong affinity only in deprotonated cases through forming stable six atoms’ ring containing alkali cation chelated by two oxygens. These results suggest that the medullary layer can catch all alkali cations in a wide pH range around the physiological one, while the upper cortex can effectively block penetration of metal ions when the metal stress grows. Such insights highlight a physiological role of metabolites like blocking of metal-cation migrations into intracellular tissues, and explain long-term retention of alkali cations including Cs in lichens containing enough such metabolites to bind them.

Conformational effect on the preferential binding of alkali metal cation with crown ether: A molecular level investigation

2009 ◽  
Vol 12 (1-3) ◽  
pp. 93-99 ◽  
Author(s):  
Sulagna De ◽  
Sk. Musharaf Ali ◽  
M.R.K. Shenoi ◽  
Sandip K. Ghosh ◽  
Dilip K. Maity
Keyword(s):  
Crown Ether ◽  
Alkali Metal ◽  
Metal Cation ◽  
Molecular Level ◽  
Alkali Metal Cation ◽  
Conformational Effect ◽  
Preferential Binding

Dynamic chiral-at-metal stability of tetrakis(d/l-hfc)Ln(iii) complexes capped with an alkali metal cation in solution

2012 ◽  
Vol 41 (22) ◽  
pp. 6696 ◽  
Author(s):  
Yiji Lin ◽  
Fang Zou ◽  
Shigang Wan ◽  
Jie Ouyang ◽  
Lirong Lin ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Metal Cation ◽  
Alkali Metal Cation
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