Germanium-8-Hydroxyquinoline hydroxides: Synthesis, structure and luminescence properties.

Graphical abstract A Ge4+-based coordination complex was obtained via a simple hydrothermal synthesis, which contains 8-Hydroxyquinoline and hydroxyl group as ligands, forms a dense 0-D structure which shows interesting photoluminescence both at room temperature and 14 K. Highlights • A new Ge-based coordination complex was hydrothermally synthesized. • 8-Hydroxyquinoline and hydroxyl group were employed as ligands. • The photoluminescence of the title complex was studied under room temperature and at low temperature. Abstract A new germanium hydroxide coordinated by 8-Hydroxyquinoline (8-HQ), C 18 H 14 GeN 2 O 4 (Hereafter, GeHQ1) was synthesized via either a hydrothermal or common solution approach. Its structure was determined with both powder XRD and single crystal X-ray diffraction techniques. GeHQ1 crystallizes in orthorhombic symmetry, space group Pbca (No. 61) with unit-cell parameters: a = 8.7537(5) Å, b = 13.9817(7) Å, c = 24.8775(13) Å, and V = 3044.8(3) Å3, Z = 8, R = 0.0337 for reflections with I >2 sigma(I) and w R = 0.0803. The structure of GeHQ1 is built up from one germanium metal center octahedrally coordinating with two 8-Hydroxyquinoline anions (8-Q) and two hydroxyl groups and each two adjacent building units are held into a dimer via extensive hydrogen-bonding interaction between two relatively closer hydroxyl groups (2.936 Å) of two adjacent molecules. The crystals were also studied by SEM (scanning electron microscopy), EDS (energy dispersive analysis of X-rays spectroscopy), FT-IR spectrum and TGA (Thermogravimetric analysis). The photoluminescence properties were investigated in room temperature as well as lower temperature (14 K). [ABSTRACT FROM AUTHOR]