Alkali–metal lon catalysis and inhibition in nucleophilic displacement reaction of phosphorus–sulfur–and carbon–based esters

Abstract

Selectivity among alkali-metal ions is a feature of a number of important biological processes. High potassium-ion and low sodium-ion concentrations are maintained in mammalian cells by Na+-K+ pumps which consume one third to one half of the ATP required by the resting cells.l.2 Selective transport of these ions across membranes by Na+-K+ ATPase enzymes creates ionic concentration gradients which control cell volume, allow for the excitability of nerve and muscle cells, and drive the active transport of sugars and amino acids across cell membranes.' Transport by the enzyme involves phosphate transfer from ATP to form a phosphoenzyme, a process that requires Na+ and Mg2+ to proceed and whose reversal is catalysed by K+.?Nerve impulses are electrical signals produced by the flow of alkali-metal ions across the plasma membrane of neurons. The action potential arises from large, selective, and transient changes

Chemical accuracy in modeling halide ion hydration from many-body representations

“…A quantitative characterization of the driving forces and molecular mechanisms that regulate ion hydration is key to the microscopic understanding of fundamental processes taking place in aqueous clusters, solutions, and interfaces, which, in turn, have major implications for different fields of science and engineering. For example, charged species are often found as intermediates in chemical reactions and catalytic processes [1,2]. In biochemistry, ions play a central role in the stabilization of biomolecules [3][4][5] as well as in mediating protein-protein interactions [6,7], intracellular signal transduction [8,9], and enzyme and nucleic acid catalysis [10][11][12][13].…”

Chemical Accuracy in Modeling Halide Ion Hydration from Many-Body Representations

“…A quantitative characterization of the driving forces and molecular mechanisms that regulate ion hydration is key to the microscopic understanding of fundamental processes taking place in aqueous clusters, solutions, and interfaces, which, in turn, have major implications for different fields of science and engineering. For example, charged species are often found as intermediates in chemical reactions and catalytic processes [1,2]. In biochemistry, ions play a central role in the stabilization of biomolecules [3][4][5] as well as in mediating protein-protein interactions [6,7], intracellular signal transduction [8,9], and enzyme and nucleic acid catalysis [10][11][12][13].…”

Kinetic and Theoretical Studies on Alkaline Ethanolysis of 4‐Nitrophenyl Salicylate: Effect of Alkali Metal Ions on Reactivity and Mechanism

“…[12] Reactions of phosphorus and sulfur centered electrophiles with EtOM have intensively been performed to investigate the role of M + ions. [6][7][8][9][10][11][12][13][14] Stabilization of the transition state (TS) as modeled by I or II has been suggested to be responsible for the catalytic effect shown by alkali metal ions because the stability of such TSs would be dependent on the nature of the nucleophile and electrophile as well as on the size of M + ions. [6,[10][11][12] However, there have been few studies on carboxylic esters [15,16] and accordingly the role of M + ions in nucleophilic substitution reactions is not well understood.…”