Molecular engineering of two-dimensional π-conjugation: expected and unexpected photophysical consequences of a simple particle-in-a-box approach

Lim, Young‐Kwan; Jiang, Xiang; Bollinger, John C.; Lee, Dongwhan

doi:10.1039/b617353e

Cited by 20 publications

(29 citation statements)

References 87 publications

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“…As we previously reported, 11 compounds 4 – 10 show intense (ε > 75000 M −1 cm −1 ) longer wavelength (λ abs,max = 415–475 nm) absorptions and blue emissions (λ em,max = 453–480 nm). Relatively small Stokes shifts (Δλ = 24–35 nm) displayed by these molecules are consistent with the rigid nature of their extended π-system and small structural rearrangements upon photoexcitation and de-excitation.…”

Section: Resultssupporting

confidence: 74%

“…The compounds 1,3,5-triformylphloroglucinol 16a and 2-iodo-4- tert -butyl-aniline 19 were prepared according to literature procedures. The syntheses of 1 , 10 2 , 12 and 4 – 10 11 have previously been reported. All air-sensitive manipulations were carried out under nitrogen atmosphere in an M.Braun glovebox or by standard Schlenk-line techniques.…”

Section: Methodsmentioning

confidence: 99%

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Conformationally Dynamic π-Conjugation: Probing Structure–Property Relationships of Fluorescent Tris(N-salicylideneaniline)s

et al. 2011

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We recently reported the design and synthesis of a series of conformationally dynamic chromophores that are built on the C3-symmetric tris(N-salicylideneaniline) platform. This system utilizes cooperative structural folding–unfolding motions for fluorescence switching, which is driven by the assembly and disassembly of hydrogen bonds between the rigid core and rotatable peripheral part of the molecule. Here, we report detailed time-resolved spectroscopic studies to investigate the structure–property relationships of a series of functionalized tris(N-salicylideneaniline)s. Time-resolved fluorescence decay spectroscopy was applied to determine the main relaxation mechanisms of these π-extended fluorophores, and to address the effects of hydrogen bonding, steric constraints, and extension of the π-conjugation on their relaxation dynamics. Our results agree well with the conformational switching model that was previously suggested from steady-state experiments. Notably, extension of the π-conjugation from peripheral aryl groups resulted in the stabilization of the excited states, as evidenced by longer lifetimes and lower non-radiative decay constants. As a consequence, an increase in the fluorescence quantum yields was observed, which could be explained by the suppression of the torsional motions about the C–N bonds from an overall increase in the quinoid character of the excited states. A combination of time-resolved and steady-state techniques also revealed intermolecular interactions through π–π stacking at higher concentrations, which provide additional de-excitation pathways that become more pronounced in solid samples.

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Section: Resultssupporting

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Conformationally Dynamic π-Conjugation: Probing Structure–Property Relationships of Fluorescent Tris(N-salicylideneaniline)s

et al. 2011

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“…Several studies on nucleophilic substitution of glyoxal with 2,6-substituted anilines to form only diimines have been reported previously. [2][3] So, we attribute these abnormal reactions to some specific reactivity of the o-aminesubstituted anilines as mentioned in the Introduction of this article. We were interested to see which rôle tertiary alkylamines like 3a-c and 3g could play in the Cannizzaro reaction.…”

Section: Reactions Of 26-diaminoanilines With Glyoxalmentioning

confidence: 91%

“…[1] However, studies on versatile, substituted primary anilines at the aromatic ring are not so numerous. For example, the substituents introduced into anilines were isopropyl groups, aromatic groups, [2] and alkyne groups [3] at the o-positions, which were used as building units of specific metal ligands for sterically demanding metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

o‐Amine‐Assisted Cannizzaro Reaction of Glyoxal with New 2,6‐Diaminoanilines

et al. 2009

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The preparation of several new o‐amine‐substituted anilines was achieved according to a new bifunctional molecular design, and their reactions with glyoxal were conducted. Cannizzaro reactions of glyoxal proceeded using specifically designed anilines, such as 2,6‐dipyrrolidinyl‐, 2,6‐dipiperidinyl‐, 2,6‐dimorpholinyl‐, and 2‐pyrrolidinyl‐aniline, which are new and can easily be synthesized by substitution of halogen‐substituted nitrobenzene with amines and subsequent reduction with hydrogen, to form α‐hydroxy acetamide and α‐amino acetamide derivatives, as a result of the Cannizzaro reaction. In comparison with the reaction of glyoxal with p‐pyrrolidinylaniline to form a common diimine product, the reaction with o‐pyrrolidinylaniline leads only to α‐hydroxy amides, strongly suggesting that the abnormal Cannizzaro reactions are attributed to the existence of basic nitrogen atoms at the o‐positions, which suppress diimine formation and assist the generation of acetamides.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“… a) Chemical structures of compounds 1 – 3 with a close‐up view of the O hydroxy H⋅⋅⋅O hydroxy H⋅⋅⋅O carbonyl hydrogen‐bonding network (shown as capped‐stick model) 11a,b. b) Energy‐minimized (PM3) structure of compound 2 in which the tris( N ‐salicylideneaniline) and BODIPY units are color‐coded with blue and red, respectively.…”

Section: Methodsmentioning

confidence: 99%

Signal‐Amplifying Resonance Energy Transfer: A Dynamic Multichromophore Array for Allosteric Switching

et al. 2007

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Kooperatives Falten und Entfalten eines dynamischen Multichromophor‐Systems führt zu einer ungewöhnlichen Signalverstärkung als Teil eines resonanten Energietransfers von der zentralen Donoreinheit auf periphere Akzeptorensembles. Die schrittweise Zugabe und Entfernung chemischer Eingangssignale liefert reversible, sigmoidale Antwortkurven in den Anschalt‐ und in den Ausschalt‐Scans (siehe Bild).

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Molecular engineering of two-dimensional π-conjugation: expected and unexpected photophysical consequences of a simple particle-in-a-box approach

Cited by 20 publications

References 87 publications

Conformationally Dynamic π-Conjugation: Probing Structure–Property Relationships of Fluorescent Tris(N-salicylideneaniline)s

Conformationally Dynamic π-Conjugation: Probing Structure–Property Relationships of Fluorescent Tris(N-salicylideneaniline)s

o‐Amine‐Assisted Cannizzaro Reaction of Glyoxal with New 2,6‐Diaminoanilines

Signal‐Amplifying Resonance Energy Transfer: A Dynamic Multichromophore Array for Allosteric Switching

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