Near-infrared emission from novel Tris(8-hydroxyquinolinate)lanthanide(III) complexes-functionalized mesoporous...

Area of Science:

• Materials Science
• Nanotechnology
• Inorganic Chemistry

Background:

• Mesoporous silica materials like SBA-15 offer high surface area and tunable porosity.
• 8-hydroxyquinoline (HQ) is a known chelating agent for metal ions, including lanthanides.
• Lanthanide complexes are of interest for their unique luminescent properties, particularly in the near-infrared (NIR) region.

Purpose of the Study:

• To synthesize novel mesoporous materials covalently functionalized with 8-hydroxyquinoline (HQ) and lanthanide complexes.
• To investigate the covalent bonding of lanthanide (Ln) ions (Er, Nd, Yb) within the HQ-functionalized SBA-15 framework.
• To characterize the luminescent properties of the resulting LnQ3-SBA-15 materials and compare them to pure LnQ3 complexes.

Main Methods:

• Synthesis of alkoxysilane modified 8-hydroxyquinoline (Q-Si).
• Preparation of Q-SBA-15 mesoporous material using Q-Si as a precursor.
• Covalent bonding of lanthanide (Ln) ions to form LnQ3-SBA-15 materials.
• Characterization using FE-SEM, XRD, TEM, nitrogen adsorption-desorption, and fluorescence spectroscopy.

Main Results:

• Successful synthesis and characterization of Q-SBA-15 and LnQ3-SBA-15 materials.
• Demonstration of intramolecular energy transfer from HQ ligands to lanthanide ions upon excitation.
• Observation of characteristic near-infrared (NIR) luminescence from Er, Nd, and Yb ions within the SBA-15 framework.
• Comparison of NIR luminescence properties between the immobilized complexes and their free counterparts.

Conclusions:

• Novel mesoporous materials (LnQ3-SBA-15) incorporating lanthanide complexes have been successfully synthesized.
• These materials exhibit efficient NIR luminescence via ligand-to-lanthanide energy transfer.
• The covalent immobilization on SBA-15 provides a robust platform for lanthanide-based luminescent materials.