On the Fluorescent, Steric and Electronic Factors Affecting the Detection of Metallic Ions Using an Imidazolyl-Phenolic Derived Fluorescent Probe

Author(s)

Orfao, Jr., Ronaldo B. ^[1] ; de Carvalho, Fabricio ^[1] ; Homem-de-Mello, Paula ^[1] ; Bartoloni, Fernando H. ^[1]

Affiliation

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre, SP - Brazil

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 28, n. 10, p. 1896-1904, OCT 2017.
• Web of Science Citations: 4

Abstract

The imidazolyl-phenolic probe used at the present study has its photophysic properties regulated by a tautomeric equilibrium. After the absorption of a photon, an excited state intramolecular proton transfer process generates a ketonic species, responsible for the 440 nm emission (in CH3CN/H2O, 95:5, v/v). Addition of Cu2+, Al3+, Cr3+ and Fe3+ suppresses emission through a combination of dynamic and static-like quenching, as indicated by Stern-Volmer plots, with a higher sensitivity for Cu2+ (KSV = 1.90 × 105 and 2.40 × 104 L mol-1, respectively, for Cu2+ and Fe3+). The trivalent ions led to the formation of a locked-enol tautomer that emits at shorter wavelengths; this coordinated compound is also quenched at metallic ions concentrations above 20 µmol L-1, due to a collisional process. When compared to another imidazolyl-phenolic probe, experimental and simulated data revealed that fluorescent, steric and electronic effects regulate their sensitivity towards the ions. (AU)

• FAPESP's process: 14/05813-2 - Use of fluorophores containing phenolic and nitrogenated groups on metal detection by light emission
• Grantee: Ronaldo Barros Orfão Junior
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/13807-7 - New tools for the study of electron transfer reactions in PS II model systems
• Grantee: Fernando Heering Bartoloni
• Support Opportunities: Regular Research Grants