Synthesis, crystal structure, and photophysical properties of a double open cubane-like Cd(II) complex based on 2-substituted-8-hydroxyquinoline

Abstract

A 2-substituted-8-hydroxyquinoline (E)-2-[2-(3-thienyl)ethenyl]-8-quinolinol (HL) was synthesized and characterized by ESI-MS, NMR spectroscopy, and elemental analysis. Using solvothermal method, a tetranuclear complex [Cd₄L₆Br₂]·6DMF (1) was fabricated by assembly of Cd(II) with HL. X-ray structural analysis shows that 1 exhibits a double open cubane-like core structure, which is bridged by six 8-hydroxyquinolinate-based ligands. The supramolecular structure of 1 features a 3-D porous solid constructed by aromatic stacking interactions, C–H···π interactions and C–H···O hydrogen bonds. The assembly of cadmium salts and HL in solution was investigated by UV–vis and photoluminescence. We also studied the thermal stability and photophysical properties (fluorescent emission, lifetime, and quantum yield) of 1. The results show that 1 emits yellow luminescence in the solid state.

Graphical Abstract

Keywords:

• 8-Hydroxyquinoline
• Tetranuclear complex
• Crystal structure
• Photophysical property

Funding

This work was financially supported by the National Natural Science Foundation of China [grant number 21201002], [grant number 21172047]; Anhui Provincial Natural Science Foundation [grant number 1308085QB22]; Provincial natural science research program of higher education institutions of Anhui province [grant number KJ2013Z028]; the Foundation of State Key Laboratory of Structural Chemistry [project number 20130016]; National Training Programs of Innovation and Entrepreneurship for Undergraduates [grant number 201210360087].