New Sensitive and Selective Chemical Sensors for Ni2+ and Cu2+ Ions: Insights into the Sensing Mechanism through DFT Methods

Manuel A. Treto-Suárez, Jorge Tapia, Yoan Hidalgo-Rosa, Dayan Páez-Hernández, Elies Molins, Ximena Zarate, Eduardo Schott

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

We report the synthesis and theoretical study of two new colorimetric chemosensors with special selectivity and sensitivity to Ni2+ and Cu2+ ions over other metal cations in the CH3CN/H2O solution. Compounds (E)-4-((2-nitrophenyl)diazenyl)-N,N-bis(pyridin-2-ylmethyl)aniline (A) and (E)-4-((3-nitrophenyl)diazenyl)-N,N-bis(pyridin-2-ylmethyl)aniline (B) exhibited a drastic color change from yellow to colorless, which allows the detection of the mentioned metal cations through different techniques. The interaction of sensors with these metal ions induced a new absorption band with a hypsochromic shift to the characteristic signal of the free sensors. A theoretical study via time-dependent density functional theory (TD-DFT) was performed. This method has enabled us to reproduce the hypsochromic shift in the maximum UV-vis absorption band and explain the selective sensing of the ions. For all of the systems studied, the absorption band is characterized by a π → π* transition centered in the ligand. Instead of Ni2+ and Cu2+ ions, the transition is set toward the σ* molecular orbital with a strong contribution of the 3dx2-y2 transition (π → 3dx2-y2). These absorptions imply a ligand-to-metal charge transfer (LMCT) mechanism that results in the hypsochromic shift in the absorption band of these systems.

Original languageEnglish
Pages (from-to)6493-6503
Number of pages11
JournalThe journal of physical chemistry. A
Volume124
Issue number32
DOIs
Publication statusPublished - 13 Aug 2020

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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