Novel lanthanidomesogens based on poly(ethylene glycol) cholesterol ether: Liquid crystal phase behavior and luminescence properties

• Published in: Journal of molecular liquids Vol. 275; pp. 402 - 408
• Main Authors: Selivanova, N.M., Gubaidullin, A.T., Haase, W., Galyametdinov, Yu.G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2019
• Subjects: Cholesterol derivatives; Lanthanide; Liquid crystals; Luminescence; Poly(ethylene glycol); Lanthanide; Cholesterol derivatives; Liquid crystals; Poly(ethylene glycol); Luminescence
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2018.11.091

Biocompatible systems with luminescent properties attract significant interest as they are broadly used in bioanalysis and medical diagnostics. This paper describes new lanthanide liquid crystals based on an oxyethylated amphiphile with a cholesterol fragment (CholEO10). The complex of physicochemical methods (polarizing optical microscopy (POM), X-ray powder diffraction, FTIR-spectroscopy and luminescent analysis) was used to study liquid crystalline, structural and optical properties of these new biomesogens. Their phase behavior was compared with the behavior a lanthanum-containing analogue without a cholesterol fragment in its structure. A rigid hydrophobic fragment was found to exert a strong influence on lyotropic mesomorphism in aqueous media. The phase transition from a lamellar mesophase to a hexagonal one was observed with decrease of the CholEO10/La3+ complex concentration and addition of water. The study of luminescent properties of CholEO10/Ln3+ complexes, where Ln3+ is Dy3+, Tb3+, or Eu3+, revealed that their characteristic emission occurs in the yellow, green and red spectral ranges. Optical characteristics of new mesogens were estimated. Mesogenic CholEO10/Tb3+ and CholEO10/Eu3+ complexes demonstrate longer lifetime of their excited state as compared with the C12EO10/Ln3+/H2O complex. [Display omitted] •New lanthanide complexes based on cholesterol conjugate are synthesized.•Unexpectedly the smectic C mesophase for CholEO10/Ln3+ is found.•The phase diagram of CholEO10/La3+/H2O system is constructed based on POM and X-ray.•CholEO10/Tb3+LC complex showed high lifetime.