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Volumn 122, Issue 9, 2000, Pages 2027-2034

Fluorescence quenching of n,π*-excited azoalkanes by amines: What is a sterically hindered amine?

Author keywords

[No Author keywords available]

Indexed keywords

ALKANE DERIVATIVE; AMINE;

EID: 0034620768     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja992508b     Document Type: Article
Times cited : (85)

References (87)
  • 29
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    • Askani, R. Chem. Ber. 1965, 98, 2551-2555.
    • (1965) Chem. Ber. , vol.98 , pp. 2551-2555
    • Askani, R.1
  • 35
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    • Hypercube, Inc.
    • HyperChem 5.0, Hypercube, Inc. 1996.
    • (1996) HyperChem 5.0
  • 37
    • 0343746016 scopus 로고    scopus 로고
    • note
    • Besides the inductive effects of the alkyl substituents, the significantly lower ionization potentials of the amines 1-3 are attributed to structural variations. Namely, planarization due to steric repulsion of the alkyl groups increases the p character of the lone pair orbital, which lowers the ionization potential (ref 31).
  • 43
    • 0342875245 scopus 로고    scopus 로고
    • note
    • The slope for this correlation was found to be 0.83 for aliphatic amines (ref 41), indicating that a difference of 1 eV in the ionization potential corresponds to an effect of only 0.83 V in the oxidation potential.
  • 65
    • 0342440718 scopus 로고    scopus 로고
    • note
    • A direct hydrogen abstraction pathway can also be included in Scheme 1, cf. ref 13, although for good donors such as amines the CT pathways are presumed to be the most important ones (ref 10-16). This conclusion can be drawn from the examination of quenchers with poor electron donor properties and similar C-H bond strengths. Their rate constants fall far short of the values measured for amines, indicating that direct hydrogen abstraction, which should be primarily dependent on the C-H bond strength, does not compete for amines (see, for example, refs 14-16).
  • 74
    • 0342875240 scopus 로고    scopus 로고
    • note
    • Such excellent structure-reactivity correlations, while common in thermal chemistry, are scarce in the photochemistry of n,π*-excited states. Structural variations, in particular for ketones, often affect the electronic configuration (n,π*-π,π* mixing or state switching), which renders definite structure-reactivity relationships difficult. In this respect, the examination of such azoalkanes presents a novel mechanistic tool, since the properties of an n,π*-excited acceptor can be fine-tuned by substituents without admixing any sizable character of the very high-lying (ref 26) π,π* state.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.