Negative solvatochromism of azo dyes derived from (dialkylamino)thiazole dimers

Kim, Jae Joon; Funabiki, Kazumasa; Muramatsu, Hiroshige; Shibata, Katsuyoshi; Kim, Sung Hoon; Shiozaki, Hisayoshi; Hartmann, Horst; Matsui, Masaki

doi:10.1039/b001697g

Cited by 28 publications

(9 citation statements)

References 13 publications

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“…The shift in the N=N↔N−N resonance is not without precedence. The importance of the N−N resonance form was invoked in a recent study of negative solvatochromism of azo dyes to rationalize a polar ground state 12. The larger driving force for favoring form B in 4 a – d than in 2 a – d can be understood by the weaker bond strength of N=N relative to the C=N and C=C bonds;13 some of the weaker N=N bonds in form A become C=N bonds in form B (Scheme ).…”

Section: Binding Energies (Kcal Mol−1) Of the Three‐component Systemsmentioning

confidence: 99%

Remote Communication between Charge Centers and Hydrogen-Bonding Sites: Possibility for a Signal Transducer?

Chao

Hwang

2001

Angew. Chem.

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Hydrogen bonding and charge interactions are both essential for molecular recognition and the self-assembly of biological macromolecules. They are also employed heavily in the design of new systems for fundamental, biological, and materials research. The influence of a charge-bearing functional group on pK a values [1] and chemical reactivity [2] has been well documented in the form of Hammett-type substituent constants in physical organic studies. Changes in the hydrogen-bonding behavior of ligands upon complexation with cationic transition metal centers have been indicated by theoretical calculations. [3] Such calculations also indicated that anions could induce a large cooperative effect in the hydrogen-bonding network of peptides. [4] Enhancement was observed experimentally in urea´carboxylate binding when the carbonyl group of the urea molecule was coordinated to a Lewis acid. [5] The optical property of [Ru(bpy) 3 ] 2 (bpy bipyridine) in a phosphodiester sensor was changed when the hydrogen-bonding sites were bound. [6] Although both hydrogen-bonding and charge-bearing sites are important in molecular recognition, interestingly, it is not common to find examples in supramolecular chemistry in which hydrogenbonding sites are designed to be controlled by a covalently bound charge-bearing substituent. Charge-assisted CÀH´´´X hydrogen bonds have been recognized in recent years [7] and metallocene complexes have been used to achieve redoxswitched binding. [8] Nevertheless, the binding sites are basically adjacent to the charged centers, and we felt that charge centers can have a more far-reaching influence on a binding site.If a charged group and a binding site can communicate with each other, one can use a three-component system (a charged group, a linker, and a binding site) as a signal transducer. The charge-bearing group can be viewed as a reaction site, whose charge state can be altered by reactions such as protonation, metalation, oxidation, reduction, or chemical transformation of a functional group. On the basis of this concept we designed test compounds 1 a ± d and 2 a ± d, and calculated the energies N X X N H H N X X N H H H n n 1a: X = CH, n = 1 1b: X = CH, n = 2 1c: X = CH, n = 3 1d: X = CH, n = 4 2a: X = CH, n = 1 2b: X = CH, n = 2 2c: X = CH, n = 3 2d: X = CH, n = 4 3a: X = N, n = 1 3b: X = N, n = 2 3c: X = N, n = 3 3d: X = N, n = 4 4a: X = N, n = 1 4b: X = N, n = 2 4c: X = N, n = 3 4d: X = N, n = 4of formation of a hydrogen bond (binding energies) to find out how efficiently the reaction and binding centers can communicate with each other. In these compounds the reaction center is an imine group and the binding center is pyrrole; compounds 1 a ± d are neutral imines and 2 a ± d are cationic iminium compounds. Ammonia was chosen as the hydrogen-bonding partner of the NÀH group of pyrrole for the sake of geometric simplicity, since it only has one lone pair of electrons. The ammonia binding energy of 2 a (À 13.17 kcal mol À1 ) at the HF/6-31G* level is double that of cationic 1 a (À 6.84 kcal mo...

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Section: Binding Energies (Kcal Mol−1) Of the Three‐component Systemsmentioning

confidence: 99%

Remote Communication between Charge Centers and Hydrogen-Bonding Sites: Possibility for a Signal Transducer?

Chao

Hwang

2001

Angew. Chem.

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“…Azo dyes with an electron withdrawing group at one side of the molecule and an electron donating group at the other side are an example of the so-called push-pull molecules which are of interest in the field of non-linear optical molecules. The lowest energy electronic transitions correspond to n-π* electronic transition gives rise to increasing the push-pull character of molecules (Kim et al 2000;Kim et al 2001 the figures, we can say that this molecule is the highest non-linear optical molecule among the investigated azo dyes, since the optic intensity of third band (n-π* electronic transition) in Az14 is comparatively larger than those of the second band (π-π* electronic transition).…”

Section: Resultsmentioning

confidence: 78%

“…These molecules comes into being hypsochromic effect depending on propeties of solvents (Kim et al 2000).…”

Section: Resultsmentioning

confidence: 99%

“…The lowest energy electronic transitions correspond to n-π* electronic transition gives rise to increasing the push-pull character of molecules (Kim et al 2000;Kim et al 2001). As seen from the all of the figures, we can say that this molecule is the highest non-linear optical molecule among the investigated azo dyes, since the optic intensity of third band (n-π* electronic transition) in Az14 is comparatively larger than those of the second band (π-π* electronic transition).…”

Section: Resultsmentioning

confidence: 99%

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An experimental study on relationship between hammett substituent constant and electronic absorption wavelength of some azo dyes

Sıdır¹,

Sıdır²,

Berber³

et al. 2015

Bitlis Eren University Journal of Science and Technology

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In this study, absorption spectra of sixteen azo dyes have been recorded in various solvents. These azo dyes have substituents such as OH, SO3H, Cl, I, NO2, C2H5 and OCH3 in different positions of phenyl ring. There is a shift in λmax whose amount is dependent upon the type and position of substituent on the ring. The effects of substituent on the absorption spectra of azo dyes are interpreted by correlation of absorption maximum wavelengths (nm) with the hammett substituent parameters. Charge transfer transitions are observed in inverse direction for azo dyes with electron acceptor substituent compared to azo dyes with electron donor.

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“…This suggests stabilization of the electronic excited state relative to the ground state. Thus, the title compound showed positive solvatochromic behavior [9,10]. …”

Section: Resultsmentioning

confidence: 99%

Synthesis, solvatochromism and crystal structure of 5-Methoxy-5,6-diphenyl-4,5-dihydro-2H −1,2,4-triazine-3-thione

Rezaei

Fazlollahi

2013

Chemistry Central Journal

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BackgroundFor the development of properties in molecular crystals, such as electrical conductivities, magnetic properties, or non-linear optical properties, not only the electronic properties of molecules themselves matter, but also the molecular arrangements in the crystals are very important. Therefore, the design of the crystal structures and the control of molecular arrangements have attracted much attention in recent years. Among various ligands, triazine moieties have been especially interesting because of their biological, pharmacological and medicinal properties.ResultsCrystal structure of 5-Methoxy-5,6-diphenyl-4,5-dihydro-2H-1,2,4-triazine-3-thione is Monoclinic, which consists of space group P21/c with a = 9.699(1), b = 8.500(1), c = 18.044(2) Å, β = 101.290(7)° and Z = 4, R1 = 0.0371 and wR2 = 0.1008 with 2456 reflections (I > 2σ(I)). Intermolecular H bonds between NH groups are acting as donors and S atoms as acceptors. There are also shorted face-to-face as well as edge to face π-π stacking interactions between the parallel aromatic rings. The behavior of solvatochromic of the mentioned compound that involved interhydrogen bonding was investigated by studying its electronic absorption spectra in pure organic solvents of different characters.ConclusionsThe crystal structure of C16H15N3OS, shows the expected face-to-face π-π stacking interactions between aromatic rings of the neighbor chains in this compound. The centroid–centroid distance between the aromatic rings is 3.325 Å. It was found that the monomer of the ligand 5-Methoxy-5,6-diphenyl-4,5-dihydro-2H-1,2,4-triazine-3-thione, further extends into 3D networks via hydrogen bonding and pi-pi stacking interactions. The solvatochromic behavior of the title compound was also investigated by studying its spectra in a selection of different organic solvents. While progressing from the non-polar solvent to the polar one, the main intense band at 310 nm, which is due to the π–π* transition, was red shifted by 13 nm. Thus, the title compound showed positive solvatochromic behavior.

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Negative solvatochromism of azo dyes derived from (dialkylamino)thiazole dimers

Abstract: The first examples of negative solvatochromism in neutral azo dyes containing both strongly electron-donating bis-(dialkylamino)thiazolyl and electron-withdrawing 4-(trifluoromethylsulfonyl)phenyl or 2-thiazolyl moieties are reported.

Cited by 28 publications

References 13 publications

Remote Communication between Charge Centers and Hydrogen-Bonding Sites: Possibility for a Signal Transducer?

Remote Communication between Charge Centers and Hydrogen-Bonding Sites: Possibility for a Signal Transducer?

An experimental study on relationship between hammett substituent constant and electronic absorption wavelength of some azo dyes

Synthesis, solvatochromism and crystal structure of 5-Methoxy-5,6-diphenyl-4,5-dihydro-2H −1,2,4-triazine-3-thione

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