Modulating the Inclusive and Coordinating Ability of Thiacalix[4]arene and Its Antenna Effect on Yb³-Luminescence via Upper-Rim Substitution.

ABSTRACT: The present work introduces the series of thiacalix[4]arenes (H₄L) bearing different upper-rim substituents (R = H, Br, NO₂) for rational design of ligands providing an antenna-effect on the NIR Yb³⁺-centered luminescence of their Yb³⁺ complexes. The unusual inclusive self-assembly of H₃L^- (Br) through Brπ interactions is revealed through single-crystal XRD analysis. Thermodynamically favorable formation of dimeric complexes [2Yb³⁺:2HL^3-] leads to efficient sensitizing of the Yb³⁺ luminescence for H₄L (Br, NO₂), while poor sensitizing is observed for ligand H₄L (H). X-ray analysis of the single crystal separated from the basified DMF solutions of YbCl₃ and H₄L(NO₂) has revealed the transformation of the dimeric complexes into [4Yb³⁺:2L^4-] ones with a cubane-like cluster structure. The luminescence characteristics of the complexes in the solutions reveal the peculiar antenna effect of H₄L(R = NO₂), where the triplet level at 567 nm (17,637 cm^-1) arisen from ILCT provides efficient sensitizing of the Yb³⁺ luminescence.

SUBMITTER: Podyachev SN 

PROVIDER: S-EPMC9609577 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature