Ferrocenyl and pyridyl methylenepyrans as potential precursors of organometallic electron-rich extended bipyrans: Synthesis, characterization and crystal structure

Ba, Fatou; Guen, Françoise Robin‐le; Cabon, Nolwenn; Poul, Pascal Le; Golhen, Stéphane; Poul, Nicolas Le; Caro, Bertrand

doi:10.1016/j.jorganchem.2009.10.006

Cited by 19 publications

(18 citation statements)

References 103 publications

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“…Irreversibility of the oxidative process emphasized the occurrence of an EC mechanism (E = Electrochemical step, C = Chemical step), for which the C step corresponds to the coupling of a radical cation either with another radical cation (RRD mechanism) or with a neutral R PhMP species (RSD mechanism). 48,49 On the basis of previous studies with analogous methylenepyrans, 40,42,43 the irreversible reduction process at ca. E pc ~ −0.8 V can be ascribed to the reduction of the electrogenerated bispyrylium species [3a-f] 2+ (see Figure 7 S7 for the CV of 3f 2+ ).…”

Section: Structural Characterisation Of Nme2 Phmp (2b)mentioning

confidence: 99%

“…37,38,40,41 The resulting bispyrylium species is reduced irreversibly around −0.8 V vs. Fc leading back to the initial methylenepyran by C−C bond breaking (Scheme 1). [40][41][42][43] Bispyrylium compounds are much less sensitive to self-deprotonation than their bisdithiolium analogues. 30,40,43 Such stability is of high importance when considering prospective application in the field of organic redox switches.…”

Section: Introductionmentioning

confidence: 99%

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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: Structural Characterisation Of Nme2 Phmp (2b)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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“…These anodic potentials should be assigned to the oxidation of the methylenepyran group which probably leads to the formation of dimer byproducts as previously observed for similar derivatives. [22], [24] Interestingly the oxidation potentials of both compounds are quite comparable. This effect should be connected to the equivalent degree of electronic conjugation between the pyran and styrylpyrimidine subunits within both chromophores which is consistent with the equivalent twisted geometries derived from DFT calculations.…”

Section: Synthesismentioning

confidence: 93%

“…[20] The second step consists in a Wittig reaction between aldehyde 1 and phosphonium salt 2 [21] leading to compound 3. [22] Quadrupolar derivative 5 has been obtained by the same synthetic procedure starting from 4,6-dimethylpyrimidine (Scheme 3). These materials are perfectly stable in the solid state and can be stored without the need for special precautions.…”

Section: Synthesismentioning

confidence: 99%

Synthesis, Photophysics and Nonlinear Optical Properties of Stilbenoid Pyrimidine‐Based Dyes Bearing Methylenepyran Donor Groups

et al. 2013

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Arnaud Spangenberg, et al.. Synthesis, photophysics and nonlinear optical properties of stilbenoid pyrimidine-based dyes bearing methylenepyran donor groups.. ChemPhysChem, Wiley-VCH Verlag, 2013, 14 (12), pp.2725-36. 10.1002 Synthesis, Photophysics and Non-linear Optical Properties of Stilbenoid Pyrimidinebased Dyes bearing Methylenepyran Donor GroupsSylvain Achelle,* [a] Jean-Pierre Malval,* [b] Stéphane Aloïse, [c] Alberto Barsella, [d] Arnaud Spangenberg, [b] Loic Mager, [d] Huriye Akdas-Kilig, [e] Jean-Luc Fillaut, [e] Bertrand Caro, [a] and Françoise Robin-le Guen [a] [ AbstractThe nonlinear properties and the photophysical behavior of two π-conjugated chromophores incorporating an electron-deficient pyrimidine core (A) and -methylenepyrans as terminal donor (D) groups have been thoroughly investigated. Both dipolar and quadrupolar branching strategies are explored and rationalized on the basis of the Frenkel exciton model. Even though a cooperative effect is clearly observed when increasing the dimensionality, the NLO response of this series is moderate when considering the nature of the D/A couple and the size of the chromophores (as measured by the number of π electrons). This effect was assigned to a disruption of the electronic conjugation within the dyes scaffold whose geometry deviates from planarity due to a noticeable twisting of the pyranylidene end-groups. This latter structural parameter has also a strong influence on the excited-state dynamics which leads to a very efficient fluorescence quenching.

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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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Ferrocenyl and pyridyl methylenepyrans as potential precursors of organometallic electron-rich extended bipyrans: Synthesis, characterization and crystal structure

Cited by 19 publications

References 103 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

Synthesis, Photophysics and Nonlinear Optical Properties of Stilbenoid Pyrimidine‐Based Dyes Bearing Methylenepyran Donor Groups

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

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