The synthesis, structure and photoluminescent properties of solid-state green to yellow emitters based on β-carboline

A series of solid-state green to yellow emitters based on β-carboline core were synthesized and characterized. The crystal structures of four of them were determined by single crystal X-ray diffraction analysis. The photoluminescent properties of β-carbolines were examined in solution and in the solid state. It was found that these fluorophores were luminescent, having solid-state emission at wavelengths ranging from 505 to 582 nm, depending on structure. Significantly, two naphthalene-carboline hybrids exhibit strong green fluorescence emission both in solution and in crystalline state. However, two methoxyl-phenyl substituted β-carboline derivative show intense green/yellow emission peaked at 540–582 nm, and display red-shifted by 40–82 nm with respect to the solution behavior. The experimental results demonstrated that the solid-state emission ranging from green to yellow can be readily tuned by simply varying molecular structure. The solid-state luminescent properties are highly dependent on the nature and position of the substituents and also on the molecular arrangements and the intermolecular interactions.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Novel β-carboline derivatives have been synthesized and characterized. ► X-Ray crystal structures of four of them have been determined. ► These fluorophores display tunable solid-state emission from green to yellow.