Phenylazoindole dyes 3: Determination of azo-hydrazone tautomers of new phenylazoindole dyes in solution and solid state

Babür, Banu; Seferoğlu, Nurgül; Aktan, Ebru; Hökelek, Tuncer; Şahin, Ertan; Seferoğlu, Zeynel

doi:10.1016/j.molstruc.2014.09.082

Cited by 25 publications

(8 citation statements)

References 35 publications

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“…Phenylazoindoles themselves are known to give rise to a hydrazone tautomerism. 36 Thus, we aimed to explain the involvement of an azo-hydrazone and why minimal modifications of the indolic core lead to a surprisingly wide span of thermal relaxation rates through a detailed computational study.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Tuning the Thermal Isomerization of Phenylazoindole Photoswitches from Days to Nanoseconds

et al. 2018

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The growing interest in light-driven molecular switches and optical oscillators led to the development of molecules that are able to interconvert from a stable to a metastable configuration upon photochemical triggering and to return to the thermodynamically stable form as soon as the light stimulus is removed. Controlling a wide range of back-isomerization lifetimes in the dark is a crucial goal for potential application of these compounds such as molecular machines. We herein present a novel class of easily synthesizable azo photoswitches based on the arylazoindole core. Most notably, minimal modifications of the core, such as methylation, dramatically change the Z-to-E thermal isomerization rate from days (Me in position 1) to the nanosecond range (Me in position 2). Moreover, fine-tuning of the Z-to-E lifetimes can be achieved choosing a proper dimethyl sulfoxide-water (or buffered water) solvent mixture. The photochemical and thermal mechanisms have been elucidated by a thorough computational and spectroscopic analysis. This allowed to detect three different pathways of thermal isomerization and to identify the hydrazone tautomer of the phenylazoindole as the major actor in the fast Z-E thermal isomerization of the NH-substituted switch in protic media.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Tuning the Thermal Isomerization of Phenylazoindole Photoswitches from Days to Nanoseconds

et al. 2018

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“…Arylhydrazones are characterized by their simple preparation and worth considering in the design of novel molecular switches with solvatochromic and pH sensing performance. A hydrazone functional group has the ability to operate as a bridge in a donor-acceptor molecular structure, or it can act itself as an electron donor moiety, when it is in conjugation with an electronwithdrawing moiety [34][35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Solvatochromic Performance, pH Sensing, Dyeing Ability, and Antimicrobial Activity of Novel Hydrazone Dyestuffs

Khattab

Allam

Othman

et al. 2019

Journal of Chemistry

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New tricyanofuran intramolecular charge transfer dyes comprising the hydrazone group were prepared and fully characterized in order to study their possible solvatochromism, dyeing ability, and antimicrobial activity. e preparation of the hydrazone dyes was achieved in relatively good yields starting from different aromatic amines. e hydrazone functional group was presented via the azo-coupling reaction of the tricyanofuran compound by the properly substituted diazonium chloride. Chemical structures of the prepared hydrazones were confirmed via nuclear magnetic resonance spectroscopy ( 1 H-and 13 C-NMR), Fourier-transform infrared spectroscopy (FT-IR), and elemental analysis (C, H, and N). e UV-visible absorption spectra of the produced sensor colorants displayed interesting solvatochromism in solvents with a different polarity, which was found to be affected by the substituents bonded to the aromatic hydrazone moiety. e pH molecular switching was investigated through tuning the intramolecular charge transfer stimulated by the reversible deprotonation/protonation process in acetonitrile solution showing color change from yellow to purple. e produced disperse dyestuffs were employed for dyeing polyester fibers to introduce acceptable color strength and colorfastness properties. Moreover, the dyes verified a weak to moderate antimicrobial activity against some selected pathogens, including S. aureus, E. coli, and Candida albicans.

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“…Their large color range, dyeing facility, and good stabilities make them highly demanding in industry. They are highly versatile for use in different fields and in technologies like chemosensing, nonlinear optics, and for optical data storage [7]. Azobenzenes are one of the most prominent classes of photo chromic molecules with two sis and trans isomers [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

DFT Study for the Spectroscopic and Structural Analysis of p-Dimethylaminoazobenzene

Ali

Mansha

Asim

et al. 2018

Journal of Spectroscopy

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The study under consideration represents the computational calculations of Azo-based direct dye named p-(dimethylamino)azobenzene (DMAB) under the effect of solvents with different relative permittivities. A density functional theory (DFT) method at the B3LYP level with 6-311G++ was applied for the spectroscopic and structural analysis of the title compound. Calculations of geometric parameters (bond orders, bond lengths, and dihedral angles), electron densities, thermodynamic parameters, and orbital energies were performed for the title compound. Mulliken population analysis (MPA) as well as natural population analysis (NPA) was also performed at the B3LYP level with different solvents for finding solvent effects. In order to predict the reactivity of DMAB, molecular electrostatic potential (MESP) calculations were carried out for it. For vibrational analysis, the infrared (IR) spectra were computed for the title compound at the B3LYP/6-311G++ level in the gas phase and in different solvents with good agreement to the experimental FT-IR spectrum. The different modes of vibrations were assigned using potential energy distribution (PED). The computed Raman spectra also showed appreciable agreement with the experimental recorded Raman spectrum. The electronic absorption spectra of the title compound have been computed employing DFT/B3LYP with the 6-311G++ basis set in the gas phase and in four different solvents, that is, DMSO, ethanol, acetonitrile, and water which were compared with the experimental spectra with appreciable agreement. NBO analysis was carried out for understanding the intramolecular and intermolecular bonding of the compound and the density transfer from completely filled to unfilled orbital was found. The HOMO-LUMO energies were determined for analyzing the mechanism of intramolecular charge transfer.

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Phenylazoindole dyes 3: Determination of azo-hydrazone tautomers of new phenylazoindole dyes in solution and solid state

Cited by 25 publications

References 35 publications

Tuning the Thermal Isomerization of Phenylazoindole Photoswitches from Days to Nanoseconds

Tuning the Thermal Isomerization of Phenylazoindole Photoswitches from Days to Nanoseconds

Synthesis, Solvatochromic Performance, pH Sensing, Dyeing Ability, and Antimicrobial Activity of Novel Hydrazone Dyestuffs

DFT Study for the Spectroscopic and Structural Analysis of p-Dimethylaminoazobenzene

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