Theoretical Study on the Formation Mechanism of Amino Acid-Cu(II) Complexes on an Enantio-Sensing Device Interface

Masahiro Kunimoto, Yusuke Sadaoka, Takuya Nakanishi, Tetsuya Osaka, Takayuki Homma

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Abstract

Theoretical analyses of l-alanine (l-Ala)- and l-homocysteine (l-Hcy)-Cu(II) complexes in basic, neutral, and acidic solutions were carried out using density functional theory to investigate the pH dependence of the formation mechanism of amino acid-Cu(II) complexes. The calculated complex formation energies indicate that the amino acid-Cu(II) complexes were expected to form in basic and neutral solutions but not in acidic solutions. The factors that determine the stability of these complexes are the coordination ability of each amino acid and the significance of intramolecular interactions among ligands within the complexes. As predicted from the molecular structure, in neutral solutions, the coordination ability of amino acid becomes lower than that in basic solutions because of the inert structure of the protonated amino group, -NH3 + however, the coordination ability originating from the -COO- group is estimated to be sufficient for stabilizing the entire complex system. Moreover, two H2O molecules coordinate with the central Cu2+ ion from the equatorial direction and interact with the coordinating amino acids, providing additional stability within the complex. In contrast, in acidic solutions, the complex does not have either sufficient coordination ability of amino acids or effective intramolecular interactions within the complex.

Original languageEnglish
Pages (from-to)15722-15728
Number of pages7
JournalJournal of Physical Chemistry C
Volume120
Issue number29
DOIs
Publication statusPublished - 2016 Jul 28

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amino acids
Amino acids
Amino Acids
Coordination Complexes
Homocysteine
energy of formation
alanine
complex systems
Alanine
Molecular structure
Density functional theory
Large scale systems
molecular structure
Ligands
interactions
Ions
density functional theory
ligands
Molecules
molecules

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Theoretical Study on the Formation Mechanism of Amino Acid-Cu(II) Complexes on an Enantio-Sensing Device Interface. / Kunimoto, Masahiro; Sadaoka, Yusuke; Nakanishi, Takuya; Osaka, Tetsuya; Homma, Takayuki.

In: Journal of Physical Chemistry C, Vol. 120, No. 29, 28.07.2016, p. 15722-15728.

Research output: Contribution to journalArticle

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