Time-Resolved Fluorescence of Salicylideneaniline Compounds in Solution

Vargas, Carolina

doi:10.1021/jp035461w

Cited by 61 publications

(44 citation statements)

References 26 publications

(63 reference statements)

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“…Previous time-resolved studies on simple N -salicylideneaniline derivatives identified two decay components with lifetimes that are similar to those observed for 1 – 3 . 36 These lifetimes were explained by invoking an isomerization between the cis -keto* and twist -keto* form of the molecule in the excited state. The feasibility of similar processes at the tris( N -salicylideneaniline) core prompted us to investigate the effects of temperature on the fractional intensities of the lifetime components.…”

Section: Resultsmentioning

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: Resultsmentioning

confidence: 99%

“…It is therefore most likely related to processes occurring at the {C 6 O 3 (CHNH) 3 } core, such as a cis -keto* to twist -keto* isomerization of the N -salicylideneaniline fragments. 36 The detailed molecular mechanism responsible for this phenomenon is yet to be elucidated.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2011

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“…Contradictions with the literature were also noted for N-salicylidene-3-aminopyridine (L 3 ), which was claimed to be exclusively thermochromic, [16] but which is actually photochromic, too, irrespective of its form (crystalline powder or single crystals; Figure 12). Surprisingly, molecules are closely packed in their crystal structure, with such characteristics being a signature, according to Hadjoudis and Mavridis, [23] of thermochromic molecules. [16,42] The existence of polymorphs could explain the conflicting observations between ref.…”

Section: Discussionmentioning

confidence: 99%

Insights into the Origin of Solid‐State Photochromism and Thermochromism of N‐Salicylideneanils: The Intriguing Case of Aminopyridines

Robert¹,

Naik²,

Tinant³

et al. 2009

Chemistry A European J

106

123

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The relationships between the crystal structure and optical properties of switchable N-salicylideneanils have been revised and discussed on the basis of new experimental results and a computational approach. N-salicylidene-3-aminopyridine (L(3)) is a versatile thermo- and photochromic molecule. It also exhibits an infinitely slow thermal back relaxation (k = 9.9x10(-8) s(-1)) after photoswitching that is suitable for optical memories. Contrary to reports in the literature, N-salicylidene-4-aminopyridine (L(4)) is exclusively thermochromic. To explain these unexpected optical properties in the solid state, crystallography combined with UV-visible spectroscopic data was exploited. L(3) was also used as a ligand in new thermochromic coordination complexes [M(CH(3)OH)(2)(L(3))(2)(NCX)(2)], in which M(II) = Fe, Co, Ni, Cu or Mn and X = S or Se (1-6), which allowed the fine-tuning of the electron density in the photochromic moiety. The influence of the coordination through the nitrogen of the pyridine ring is also fully discussed.

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“…[38] The photochemical process associated to the photochromism has been described. [39][40][41] UV irradiation (Figure 1b) of the enol form leads to the formation of the excited enol form (enol*). This species can fluoresce in the visible region in some rare cases [42] or complete a fast tautomerization to the excited cis-keto form (cis*).…”

Section: Introductionmentioning

confidence: 99%

Engineering Solid‐State Molecular Switches: N‐Salicylidene N‐Heterocycle Derivatives

et al. 2010

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A supramolecular engineering approach has been developed for a novel family of N-salicylidene aniline derivatives to control their thermo-and photochromic behaviours. Hsaltrz, Habs, Hsalphen, Hsaltz and Ksaltz are versatile molecules built from N-heterocycles, which drive the molecular arrangement to form a controlled crystal packing with predesigned optical properties. A complete structural, optical and computational study of powders of these new molecular nanoswitches is presented. An N-salicylidene aniline derivative possessing no thermo-or photoinduced chromic properties thanks to a specific molecular geometry was sought, and Habs and Hsalphen were designed to enhance π-π stacking

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Time-Resolved Fluorescence of Salicylideneaniline Compounds in Solution

Cited by 61 publications

References 26 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

Insights into the Origin of Solid‐State Photochromism and Thermochromism of N‐Salicylideneanils: The Intriguing Case of Aminopyridines

Engineering Solid‐State Molecular Switches: N‐Salicylidene N‐Heterocycle Derivatives

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