Axial complexes of Sn(IV)-tetra(4-sulfophenyl)porphyrin with azorubine in aqueous media: Fluorescent probes of local viscosity and pH indicators

• Published in: Journal of molecular liquids Vol. 366; p. 120277
• Main Authors: Mamardashvili, G.M., Kaigorodova, E.Yu, Lebedev, I.S., Mamardashvili, N.Z.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-11-2022
• Subjects: Azo-dye; local viscosity and pH sensor; Molecular rotor; Sn(IV)-porphyrin; Sn(IV)-porphyrin; Azo-dye; Molecular rotor; local viscosity and pH sensor
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2022.120277

[Display omitted]
•A triad consisting of two azorubine ligands and sn-tetra(sulfophenyl)porphyrin has been synthesized.•Spectral-luminescent properties of the triad and its components in aqueous media have been studied.•The triad exhibits tunable sensitivity to the medium pH and local viscosity for each specific case.
A triad (Az-SnP-Az) consisting of two azorubine ligands (Az) axially bonded to the sulfo-derivative of Sn(IV)-tetraphenylporphyrin [SnP(OH)2] has been synthesized. The triad structure is optimized by quantum chemical calculations and confirmed by a complex of physicochemical methods. The spectral-luminescent properties of the triad and its components in aqueous media have been studied. The sensitivity of the photophysical characteristics of the triad to the concentration-dependent viscosity of the solution has been studied on a model system (binary solvent glycerol-water). It has been established that the resulting triad has the properties of a molecular rotor and exhibits high sensitivity to local viscosity at the Az and SnP absorption maxima. The ability to tune the wavelength of the radiation, allows configuring the created “molecular rotor” to monitor the local viscosity for each specific case.