4- and 5-arylethynyl water-soluble Mannich bases and related quaternary ammonium salts were synthesized and investigated as a model of conjugated quinone methide precursors (QMPs) by UV-vis light activation. Preparative photohydration and trapping reactions by thiols were studied, together with the detection of both transient QMs and competing QMP lowest triplet excited states (T1), by laser flash photolysis. The efficiency of the arylethynyl derivatives as QMPs was remarkably affected by structural features (i.e., conjugating arylethynyl moieties, substituents, and leaving groups) and protic vs aprotic solvation. Our collective data clarify the dichotomy in the photoreactivity of conjugated Mannich bases and related quaternary ammonium salts as alkylating agents and singlet oxygen sensitizers.

Conjugation, Substituent, and Solvent Effects on the Photogeneration of Quinone Methides

DORIA, FILIPPO;LENA, ALBERTO;FRECCERO, MAURO
2016-01-01

Abstract

4- and 5-arylethynyl water-soluble Mannich bases and related quaternary ammonium salts were synthesized and investigated as a model of conjugated quinone methide precursors (QMPs) by UV-vis light activation. Preparative photohydration and trapping reactions by thiols were studied, together with the detection of both transient QMs and competing QMP lowest triplet excited states (T1), by laser flash photolysis. The efficiency of the arylethynyl derivatives as QMPs was remarkably affected by structural features (i.e., conjugating arylethynyl moieties, substituents, and leaving groups) and protic vs aprotic solvation. Our collective data clarify the dichotomy in the photoreactivity of conjugated Mannich bases and related quaternary ammonium salts as alkylating agents and singlet oxygen sensitizers.
2016
The Organic Chemistry/Polymer Science category includes resources concerned with the related fields of organic chemistry and polymer science. The organic chemistry resources deal with compounds of carbon with the exception of certain simple ones, such as the carbon oxides, carbonates, cyanides and cyanates (see Inorganic & Nuclear Chemistry). This category includes research on synthetic and natural organic compounds that may include other elements, such as hydrogen and oxygen, but also nitrogen, halogens, sulphur and phosphorous. Resources concerned with hydrocarbons, organic compounds containing only the elements carbon and hydrogen, are also included in this category. Examples are the alkanes, alkenes, alkynes and aromatics, such as benzene and naphthalene. Polymer science includes all resources dealing with the study, production and technology of polymers, which are compounds composed of very large molecules made up of repeating molecular units (monomers). Polymers may be natural substances, such as polysaccharides or proteins, or synthetic materials, such as nylon or polyethylene.
Esperti anonimi
Inglese
Internazionale
STAMPA
81
9
3665
3673
9
Organic Chemistry
http://pubs.acs.org/joc
no
4
info:eu-repo/semantics/article
262
Doria, Filippo; Lena, Alberto; Bargiggia, Riccardo; Freccero, Mauro
1 Contributo su Rivista::1.1 Articolo in rivista
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1163294
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