The synthesis of flexible tetrapyridylethanes from pyridylpyrylium dications

Poul, Pascal Le; Poul, Nicolas Le; Golhen, Stéphane; Guen, Françoise Robin‐le; Caro, Bertrand

doi:10.1039/c5nj03257a

Cited by 4 publications

(4 citation statements)

References 29 publications

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“…The two-step synthesis of the bispyran compound 4f was undertaken following a previously described procedure (Scheme 3). 47 During the first step, addition of the oxidizing agent AgBF 4 to a solution of 2f in CH 2 Cl 2 led to the formation of a bispyrylium derivative 3f 2+ . Compound 3f 2+ was isolated and characterized by 1 H NMR, 13 C NMR, mass spectrometry, and cyclic voltammetry (see the Experimental Section and SI).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Reversible Redox Switching of Chromophoric Phenylmethylenepyrans by Carbon–Carbon Bond Making/Breaking

et al. 2017

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Electrochromic organic systems that can undergo substantial variation of their optical properties upon electron stimulus are of high interest for the development of functional materials. In particular, devices based on radical dimerization are appropriate because of the effectiveness and speed of carbon-carbon bond making/breaking. Phenylmethylenepyrans are organic chromophores which are well suited for such purposes since their oxidation leads to the reversible formation of bispyrylium species by radical dimerization. In this paper, we show that the redox and spectroscopic properties of phenylmethylenepyrans can be modulated by adequate variation of the substituting group on the para position of the phenyl moiety, as supported by DFT calculations. This redox switching is reversible over several cycles and is accompanied by a significant modification of the UV-vis spectrum of the chromophore, as shown by time-resolved spectroelectrochemistry in thin-layer conditions.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Reversible Redox Switching of Chromophoric Phenylmethylenepyrans by Carbon–Carbon Bond Making/Breaking

et al. 2017

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“…The generated bis-pyrylium compounds can be reduced chemically and electrochemically to yield back the initial MPs. Our experimental and computational studies on a series of substituted-MPs have emphasized that the redox and spectroscopic properties of these compounds could be modulated by adequate variation of the substituting group [26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Insights into the radical-radical and radical-substrate dimerization processes for substituted phenylmethylenepyrans

Wojcik

López

Gauthier

et al. 2019

Electrochimica Acta

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The electrochemically-induced C-C bond making/breaking for six differently R-substituted phenylmethylenepyrans has been investigated by voltammetry in organic media. All compounds display an irreversible oxidation peak whose potential is fully dependent on the electrophilic property of the substituent R. The electrochemical oxidation yields bis-pyrylium compounds by σ-σ C-C bond formation. The initial methylenepyrans are recovered by cleavage of the C-C bond through electrochemical reduction of the bis-pyrylium species.According to the voltammetric analysis, the mechanistic pathway, radical-radical or radicalsubstrate, for the intermolecular dimerization is fully R-dependent. Electronic structure M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2 calculations show that the spin population in the radical cation and the strength of the σ-σ C-C bond in the dimer strongly depend on the nature of R. In addition, low-temperature electrochemical voltammetry (175 K), and room-temperature high scan rate cyclic voltammetry have been used to unravel the kinetics of the C-C bond formation. Keywords : radical dimerization ; methylenepyran ; low-temperature voltammetry ; C-C bond making ; ab initio calculations.applications in the domain of redox switches and electrochromic devices for systems displaying optical properties in the UV-Visible spectroscopic domain [9,11,[16][17][18][19][20]. Among them, methylenepyrans (MPs) are organic molecules which have been fully exploited as dyes for photovoltaic cells [21], but also as component parts of push-pull compounds for non-linear optic (NLO) applications and luminescent devices [22][23][24]. As their dithiafulvalene (DTF)

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“…), 1382 (C=S). 1 H NMR (CD2Cl2, 400 MHz): δ 8.49 (s, 1H), 7.78(d, J = 4.4 Hz, 1H), 7.12 (d, J = 4.4 Hz, 1H), 6.98 (d, J = 2.1 Hz, 1H), 6.62 (d, J = 3.7 Hz, 1H), 6.17 (d, J = 2.1 Hz, 1H), 5.85(d, J = 3.7 Hz, 1H), 4H), 2.93 (s, 6H), 15H), 1.19 (s, 9 H). 13 C{ 1 H} NMR (CD2Cl2, 100 MHz): δ 179.…”

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confidence: 99%

“…IR (KBr): ν (cm -1 ) 2923 (Csp 3 -H), 2224 (C≡N), 1749 (C=O), 1659 (C=C), 1604 and 1543 (C=C, Ar.). 1 H NMR (CD2Cl2, 400 MHz): δ 7.64-7.59 (m, 5H), 7.42(d, J = 4.3 Hz, 1H), 7.02 (d, J = 4.3 Hz, 1H), 6.73 (s, 1H), 6.62 (d, J = 2.1 Hz, 1H), 6.61 (d, J = 3.8 Hz, 1H), 6.12 (d, J = 2.1 Hz, 1H), 5.81 (d, J = 3.8 Hz, 1H), 2.92 (s, 6H), 1.24 (s, 9H), 1.17 (s, 9H). 13 C{ 1 H} NMR: not registered due to its low solubility.…”

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Twisted One-Dimensional Charge Transfer and Related Y-Shaped Chromophores with a 4H-Pyranylidene Donor: Synthesis and Optical Properties

et al. 2021

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Three series of push-pull derivatives bearing 4H-pyranylidene as electron donor group and a variety of acceptors were designed. On the one side, one dimensional chromophores with a thiophene ring (series 1H) or 5-dimethylaminothiophene moiety (series 1N) as auxiliary donor, non-coplanar with the p-conjugated system, were synthesized. On the other side, related two-dimensional (2D) Y-shaped chromophores (series 2) were also prepared to compare how the diverse architectures affect the electrochemical, linear and second-order nonlinear optical (NLO) properties. 2The presence of the 5-dimethylaminothiophene moiety in the exocyclic C=C bond of the pyranylidene unit gives rise to oxidation potentials rarely low, and the protonation (with an excess of trifluoroacetic acid) of its derivatives results in the apparition of a new blue-shifted band in the UV-visible.The analysis of the properties of derivatives with and without the additional thiophene ring shows that this auxiliary donor leads to a higher NLO response, accompanied by an enhanced transparency.Y-shaped chromophores of series 2 present a blue-shifted absorption, higher molar extinction coefficients and higher Eox values compared to their linear twisted counterparts. As concerns NLO properties, 2D Y-shaped architecture gives rise to somewhat lower µb values (except for thiobarbiturate derivatives)

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The synthesis of flexible tetrapyridylethanes from pyridylpyrylium dications

Cited by 4 publications

References 29 publications

Reversible Redox Switching of Chromophoric Phenylmethylenepyrans by Carbon–Carbon Bond Making/Breaking

Reversible Redox Switching of Chromophoric Phenylmethylenepyrans by Carbon–Carbon Bond Making/Breaking

Insights into the radical-radical and radical-substrate dimerization processes for substituted phenylmethylenepyrans

Twisted One-Dimensional Charge Transfer and Related Y-Shaped Chromophores with a 4H-Pyranylidene Donor: Synthesis and Optical Properties

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