Hydration and dynamics of l-glutamate ion in aqueous solution. Issue 2 (7th January 2021)

• Record Type: Journal Article
• Authors: Friesen, Sergej; Fedotova, Marina V.; Kruchinin, Sergey E.; Buchner, Richard
• Is Part Of: Physical chemistry chemical physics. Volume 23:Issue 2(2020)
• Page Start: 1590
• Page End: 1600
• Publication Date: 2021-01-07
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp05489e
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Dilute l -glutamate affects water dynamics beyond its 1st hydration shell but above 0.4 M only H2 O surrounding carboxylate moieties is involved. Abstract : Aqueous solutions of sodium l -glutamate (NaGlu) in the concentration range 0 < c /M ≤ 1.90 at 25 °C were investigated by dielectric relaxation spectroscopy (DRS) and statistical mechanics (1D-RISM and 3D-RISM calculations) to study the hydration and dynamics of the l -glutamate (Glu − ) anion. Although at c → 0 water molecules beyond the first hydration shell are dynamically affected, Glu − hydration is rather fragile and for c ≳ 0.3 M apparently restricted to H2 O molecules hydrogen bonding to the carboxylate groups. These hydrating dipoles are roughly parallel to the anion moment, leading to a significantly enhanced effective dipole moment of Glu − . However, l -glutamate dynamics is determined by the rotational diffusion of individual anions under hydrodynamic slip boundary conditions. Thus, the lifetime of the hydrate complexes, as well as of possibly formed [Na + Glu − ] 0 ionpairs and l -glutamate aggregates, cannot exceed the characteristic timescale for Glu − rotation.