Density-Functional Theory Study of the Optical Isomerization of Valine Trivalent Cobalt Complexes in Physiological Environments
The M06 method of density functional theory,combined with the SMD solvent effect model of self-consistent reaction field theory,was used to study the mechanism of the optical isomerization of valine trivalent cobalt(Val→Co3+)in a physiological environment(aqueous-liquid phase,1.013×105 Pa,310.15 K).It was found that the optical isomerization of Val→Co3+can be realised in reaction channels such as H protons acting as migratory bridges with N and O atoms as well as O and N atoms in association.The energy map calculations of the reaction course stationary points show that the reaction with H migrating with O as a bridge is advantageous under the implicit solvent effect,and the reaction with H migrating with O in combination with N as a bridge and with N as a bridge is disadvantageous,and the free energy barriers for the tachyonic steps are 168.9,191.3,and 194.2 kJ/mol,respectively.The reaction in which H migrates with O as a bridge remains the most dominant under dominant solvent effects,and the free energy barrier for the tachyon step drops to between 69.2 and 69.6 kJ/mol.The results of the study show that the rate of optical isomerization of Val→Co3+in physiological environments is slightly inferior to that of the mild reaction,and that valine trivalent cobalt can only be used for short-term use in life forms for supplementation of cobalt and valine.
trivalent cobalt ionsvalinedensity functional theorysolvent effectoptical isomerizationreaction energy barriers
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