NMR spectroscopic, linear and non-linear optical properties of 1,3-benzothiazol-2-yl-(phenylhydrazono)acetonitrile (BTPA) azo dye

• Published in: Journal of molecular structure 2019-03, Vol.1179, p.315-324
• Main Authors: Alsoghier, H.M., Selim, M.A., Salman, H.M.A., Rageh, H.M., Santos, M.A., Ibrahim, S.A., Dongol, M., Soga, T., Abuelwafa, A.A.
• Format: Article
• Language: English
• Subjects: BTPA; Donor-acceptor azo dye; Intramolecular charge transfer (ICT); ITO thin film; NMR; Non-linear optical properties
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2018.11.004

The azo dye 1,3-benzothiazol-2-yl-(phenylhydrazono)acetonitrile (BTPA) was synthesized and structurally characterized by different spectroscopic techniques, including two dimensional 1H and 13C NMR as well as optical absorption and emission spectra. The obtained spectroscopic results and semiempirical PM6 calculations allowed to clarify the tautomerization phenomenon of this azo dye. Predominantly, this compound exists in Z-hydrazone form, reinforced through intramolecular hydrogen bonding, in chloroform. The X-Ray Diffraction (XRD) measurements revealed that the BTPA powder is crystallized in monoclinic system structure with the space group P1. BTPA/ITO thin film was prepared by the spin coating technique. The results of XRD for the powder and BTPA/ITO thin films confirmed the existence of nanostructural features. Analysis of the absorption edges for BTPA/ITO thin film gives direct optical band gap (2.6 eV). Lastly, the third order nonlinear susceptibility χ(3) and nonlinear refractive index n(2) were calculated in the wavelengths range 300–2500 nm. These attractive ÷(3) and n(2) results indicated that BTPA has potential applications in optoelectronics and photonics. [Display omitted] •The investigated (BTPA) dye exist predominantly in Z-hydrazone tautomeric form in chloroform solution and solid state.•Intramolecular charge transfer (ICT) π–π* transition is observed from the donor phenyl ring to the acceptor benzothiazole ring in the investigated (BTPA) dye.•Nanostructural BTPA/ITO system was prepared by low cost spin coating technique.•The non-linear optical properties were estimated using empirical relation.