Optical and electrochemical properties of ethynylaniline derivatives of phenothiazine, phenothiazine-5-oxide and phenothiazine-5,5-dioxide

Thériault, Kim D.; Sutherland, Todd C.

doi:10.1039/c4cp00678j

Cited by 29 publications

(24 citation statements)

References 57 publications

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“…Owing to their ubiquitous nature, it is unsurprising that organic compounds constitute as ignificant group within the EC materials currently available. This includes the popularc lass of molecules known as the viologens, [2,12,13] as well as many other types of organic systems such as conducting polymers (e.g., PEDOT,p olyaniline, polythiophene), [6,[14][15][16] phenothiazine derivatives, [17,18] perylene and relatedd iimides, [19][20][21] and others. [22,23] We have recently reported that the one-electrone lectrochemicalr eduction of aromatic oxygen and sulfur para-substituted diesters induces intense colorc hanges, and have estimated their contrastr atios and chromatic efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Primary‐Colored Electrochromism of 1,4‐Phenylenediamines

Lauw

Webster

2015

ChemPlusChem

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Ten 1,4‐phenylenediamines were studied using electrochemical techniques (voltammetry and controlled potential electrolysis) and UV/Vis spectroscopy under ambient conditions. All compounds demonstrated vibrant color changes upon one‐electron electrochemical oxidation in acetonitrile, with most displaying a primary color (red, green, blue, or yellow) in their oxidized state. The four electrochromes that exhibited the most intense color changes were examined by using a gold micromesh electrode laminated inside a polymer film to determine their electrochromic properties in solution (contrast ratios, chromatic efficiency, and cycle life). Their colored radical cations were also characterized by electron paramagnetic resonance spectroscopy as well as monitored for color retention over a period of 24 hours. Notably, only relatively small potentials were required to initiate the chromatic changes and the oxidized forms of the compounds were long‐lived and unaffected by atmospheric oxygen or moisture.

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Section: Introductionmentioning

confidence: 99%

Primary‐Colored Electrochromism of 1,4‐Phenylenediamines

Lauw

Webster

2015

ChemPlusChem

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“…It was found computationally that analogous to 2a, the core of p-extended compound 4a maintains its planarity, while the core of 4b is bent in a similar fashion to parent compound 2b. In a previous report 19 of a related compound whereby the carbonyl of 4a was replaced with a sulfoxide, the ground state and excited state structures showed large changes. The same computational study of ground state and excited state optimized geometries were carried out here with 4a and 4b and showed minimal structural change in the ground versus excited states.…”

Section: Synthesis and Structurementioning

confidence: 94%

“…Knoevenagel condensations of 2a and 3a with malononitrile 13 resulted in the analogous dicyanomethylene precursors 2b and 3b, respectively, in approximately 70% yield. Both dibromo-precursors, 3a and 3b, were subjected to Sonogashira cross coupling conditions with N-dialkylated-ethynylaniline 19,27 to produce the two D-A-D chromophores 4a and 4b, in 58% and 73% yield, respectively. Single crystals of the final compounds were elusive.…”

Section: Synthesis and Structurementioning

confidence: 99%

“…[13][14][15][16] This literature gap is surprising because its p-extended congener, quinacridone, has been studied extensively and has proven to be a robust pigment molecule with low HOMO-LUMO energy gaps. 17,18 Previously, we reported an electron donating organic system using a phenothiazine core 19 however, their optical HOMO-LUMO energy gap was quite large (3.2 eV), limiting their use as visible-light chromophores. Here, we conceptually replace the electron-rich thiazine ring with an electron-deficient pyridinone ring with the goal of achieving a lower energy LUMO.…”

Section: Introductionmentioning

confidence: 98%

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Structure–property relationship of donor–acceptor acridones – an optical, electrochemical and computational study

Thériault

Radford

Parvez

et al. 2015

Phys. Chem. Chem. Phys.

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The synthesis of two neutral acridone derivatives was carried out to design media sensitive chromophores by taking advantage of intramolecular charge transfer (ICT) features. The molecules comprised two different donor-acceptor-donor triads, with absorption maxima at 425 nm and 520 nm, for the ketone and dicyanomethylene derivatives, respectively. The ketone variant exhibited fluorescence at room temperature, whereas the dicyanomethylene derivative was only emissive in frozen hexane. The ketone emission was highly solvatochromic, with Stokes shifts that ranged from 5000 cm(-1) to 10 000 cm(-1). Electrochemically, both compounds displayed similar oxidation potentials at approximately 0.35 V versus ferrocene/ferrocenium, which was anticipated since both systems employ the same ethynylaniline donor portion of the molecule, whereas only the 9-dicyanomethylene derivative showed a reduction peak at -1.5 V vs. Fc/Fc(+). Additional spectroelectro-chemical experiments supported a delocalized cationic charge on the ethynylaniline fragments during oxidation and that during electrochemical reduction the dicyanomethylene moieties show localized anionic charge. All of the experimental observations are finally compared to DFT, TDDFT and NICS(0) computations to gain insight into the transitions involved and deduce the role of the acridone core in stabilizing its oxidized and reduced forms.

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“…In contrast, they have a planar structure when they have positive charges. A recent report also indicated planarity of phenothiazine rings increases in their excited state [16]. According to Cambridge Structural Database (CSD) [17], 26 structures of planar phenothiazines have been reported, including those of 22 charged phenothiazines.…”

Section: Introductionmentioning

confidence: 99%

Anomalous planar structure observed in (E)-10-(1,2-dibromoprop-1-en-1-yl)-10H-phenothiazine

Umezono

Okuno

2015

Journal of Molecular Structure

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Both Z and E isomers of 10-(1,2-dibromoprop-1-en-1-yl)-10H-phenothiazine were given by bromine addition to 10-(prop-1-yn-1-yl)-10H-phenothiazine with little stereoselectivity. The crystal structure of the Z isomer showed a usual butterfly structure, while that of the E isomer afforded an anomalous planar structure which was usually observed in positively charged phenothiazines. The reason for the planar structure was concluded to originate in intermolecular charge transfer interaction through the C-Br••• halogen bonds. X-ray crystallographic data were collected at-180 °C on a RIGAKU Saturn 724+ CCD device with using multi-layered mirror monochromatic Mo Kα radiation. The structures were solved by a direct method (SIR92) [23], and were refined by full-matrix least squares method (Shelxl97) [24]. The positions of non-H atoms were obtained from difference Fourier maps and were refined anisotropically. The C-bound H atoms except for disordered methyl protons were obtained by calculation and were refined as riding on their parent C atoms. U iso (H) values of the H atoms were set at 1.2U eq. 2-3. DFT calculations DFT calculations were performed on the GAMESS software [25,26] with B3LYP 6-31G (d,p) level. The geometrical optimization was carried out with C1 symmetry, where the initial structures for calculations were set at those obtained by single crystal XRD or by calculations of RHF 6-31G(d) level. 2-4. Materials Bromine addition to 10-(prop-1-yn-1-yl)-10H-phenothiazine A bromine solution in benzene (0.100 M, 1.00 mL) was added to a solution of 10-(prop-1-yn-1-yl)-10H-phenothiazine (23.8 mg, 0.100 mmol) in benzene (2.00 mL) at 5-10 °C and the solution was stirred for 1 hours. It was poured into a saturated sodium thiosulfate solution. The organic layer was washed with water and dried over anhydrous sodium sulfate. After removal of sodium sulfate, it was concentrated by a rotary evaporator. Judged by the 1 H NMR spectrum and yield of the residue, conversion of the addition was 90 %, and the Z/E ratio was estimated to be 40/60. The residue was purified by column chromatography on an alumina with hexane as an eluent to give the Z and E isomers of 10-(1,2-dibromoprop-1-en-1-yl)-10H-phenothiazine in 9.90 mg (yield 24.9 %) as a white powder and 5.39 mg (yield 13.6 %) as a pale yellow powder, respectively.

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Optical and electrochemical properties of ethynylaniline derivatives of phenothiazine, phenothiazine-5-oxide and phenothiazine-5,5-dioxide

Abstract: Modifications in the sulfur oxidation state of phenothiazine results in dramatic changes to the excited-state geometry with little effect on the HOMO energy.

Cited by 29 publications

References 57 publications

Primary‐Colored Electrochromism of 1,4‐Phenylenediamines

Primary‐Colored Electrochromism of 1,4‐Phenylenediamines

Structure–property relationship of donor–acceptor acridones – an optical, electrochemical and computational study

Anomalous planar structure observed in (E)-10-(1,2-dibromoprop-1-en-1-yl)-10H-phenothiazine

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