Highly chemically and thermally stable lanthanide coordination polymers for luminescent probes and white light emitting diodes

A series of isomorphic of highly chemically and thermally stable lanthanide coordination polymers exhibit luminescent probe and warm white-light emission.

Temperature-induced 1D lanthanide polymeric frameworks based on Lnn (n = 2, 2, 4, 6) cores: synthesis, crystal structures and luminescence properties

1D lanthanide polymeric frameworks were synthesized. White-light emission by two-/three-component complexes was realized. A Eu(iii)-complex could detect nitrobenzene and Ni²⁺ ion via a fluorescence quenching mechanism.

Formation of one-dimensional helical columns and excimerlike excited states by racemic quinoxaline-fused [7]carbohelicenes in the crystal

A series of quinoxaline-fused [7]carbohelicenes (HeQu derivatives) was designed and synthesized to evaluate their structural and photophysical properties in the crystal state. The quinoxaline units were expected to enhance the light-emitting properties and to control the packing structures in the crystal. The electrochemical and spectroscopic properties and excited-state dynamics of these compounds were investigated in detail. The first oxidation potentials of HeQu derivatives are approximately the same as that of unsubstituted reference [7]carbohelicene (Heli), whereas their first reduction potentials are shifted to the positive by about 0.7 V. The steady-state absorption, fluorescence, and circular dichroism spectra also became redshifted compared to those of Heli. The molecular orbitals and energy levels of the HOMO and LUMO states, calculated by DFT methods, support these trends. Moreover, the absolute fluorescence quantum yields of HeQu derivatives are about four times larger than that of Heli. The structural properties of the aggregated states were analyzed by single-crystal analysis. Introduction of appropriate substituents (i.e., 4-methoxyphenyl) in the HeQu unit enabled the construction of one-dimensional helical columns of racemic HeQu derivatives in the crystal state. Helix formation is based on intracolumn π-stacking between two neighboring [7]carbohelicenes and intercolumn CH⋅⋅⋅N interaction between a nitrogen atom of a quinoxaline unit and a hydrogen atom of a helicene unit. The time-resolved fluorescence spectra of single crystals clearly showed an excimerlike delocalized excited state owing to the short distance between neighboring [7]carbohelicene units.