Líquido iônico [bmim.PF6] como solvente: um meio conveniente para estudos por fotólise por pulso de laser

Bertoti, Ada Ruth; Netto‐Ferreira, José Carlos

doi:10.1590/s0100-40422009000700040

Cited by 5 publications

(1 citation statement)

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“…This chiral induction process is derived from the interaction of deprotonated diacids' ion pair with the ionic liquid's cation. [10].…”

Section: Introductionmentioning

confidence: 99%

Absolute Rate Constants for the Reaction of Benzil and 2,2’-Furil Triplet with Substituted Phenols in the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate. A Nanosecond Laser Flash Photolysis Study

Netto-Ferreira,

Bertoti

2024

Preprint

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The triplet excited state reactivity towards phenolic hydrogen of the -diketones benzil and 2,2´-furil in the ionic liquid 1-n-butyl-3-methyl imidazolium hexafluorophosphate [bmim.PF6] was investigated employing the nanosecond laser flash photolysis technique. Irradiation (lmax=355 nm) of benzil yields its triplet excited state with lmax at 480 nm and tT=9.6 μs. Under the same conditions, 2,2’-furil shows a triplet-triplet absorption spectrum with bands at 380, 410, 450, and 650 nm and tT=1.4 μs. Quenching rate constants (kq) of the reaction between benzil triplet and substituted phenols ranged from 1.4x107 L mol-1 s-1 (para-chlorophenol) to 1.8x108 L mol-1 s-1 (para-methoxyphenol). A new transient was formed in all cases, assigned to the benzil ketyl. Similar results were obtained for the quenching of 2,2’-furil triplet by phenols, for which kq ranged from 1.9x108 L mol-1 s-1 (para-chlorophenol) to 2.2x108 L mol-1 s-1 (para-methoxyphenol). The 2,2’-furil ketyl radical was also observed in all cases (lmax=380 nm). The quenching rate constants are almost independent of the substituent and diffusion-controlled (kq ~ 108 L mol-1 s-1). The proposed mechanism for the phenolic hydrogen abstraction by benzil and 2,2´-furil triplet may involve a proton-coupled electron transfer reaction, ultimately leading to the radical pair ketyl/aryloxyl.

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“…This chiral induction process is derived from the interaction of deprotonated diacids' ion pair with the ionic liquid's cation. [10].…”

Section: Introductionmentioning

confidence: 99%