# Photo-physical and structural studies of some synthesized arylazoquinoline dyes.
> アリールアゾキノリン系色素の光物理的特性および構造解析


## Abstract

Seven azoquinoline dyes bearing various substituents, along with newly synthesized methylated analogs, were characterized by electronic spectroscopy across multiple solvent environments including ordinary, multifunctional, and ordered liquid media. Solvatochromic, tautomeric, halochromic, and dichroic properties were evaluated under both acidic and basic conditions. Multi-parameter polarity scales were applied to correlate spectral shifts with solvent properties. Ionization constants were determined in ethanol-water mixtures. At elevated dye concentrations, intermolecular hydrogen bonding was found to predominate over intramolecular interactions, stabilizing the azo tautomeric form as the principal species. Orientation behavior in liquid crystal matrices confirmed the dominance of the azo form in highly polar anisotropic media. Time-dependent density functional theory calculations provided additional insight into the electronic transitions of representative compounds.

### Mechanism

At high dye concentrations, intermolecular hydrogen bonding becomes more stable than intramolecular hydrogen bonding, favoring the azo tautomeric form as the predominant species in solution.

## Bibliographic

- **Authors**: Ghanadzadeh Gilani A, Taghvaei V, Moradi Rufchahi E, Mirzaei M
- **Journal**: Spectrochim Acta A Mol Biomol Spectrosc
- **Year**: 2017 (2017-10-05)
- **PMID**: [28551448](https://pubmed.ncbi.nlm.nih.gov/28551448/)
- **DOI**: [10.1016/j.saa.2017.05.035](https://doi.org/10.1016/j.saa.2017.05.035)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 28551448. https://h2-papers.org/en/papers/28551448
> **Source**: PubMed PMID [28551448](https://pubmed.ncbi.nlm.nih.gov/28551448/)