Solvent-mediated crystal-to-crystal interconversion between discrete lanthanide complexes and one-dimensional...

Area of Science:

• Inorganic Chemistry
• Materials Science
• Coordination Chemistry

Background:

• Lanthanide-based coordination polymers and discrete complexes are of interest for their unique luminescent properties.
• The synthesis and structural characterization of isostructural coordination polymers and discrete complexes provide insights into structure-property relationships.
• Solvent-mediated transformations in crystalline materials offer opportunities for dynamic material design.

Purpose of the Study:

• To synthesize and characterize novel 1D coordination polymers and discrete complexes of Eu(3+) and Tb(3+).
• To investigate the structural differences and coordination geometries of the synthesized lanthanide complexes.
• To explore the solvent-mediated crystal-to-crystal transformation and luminescence sensing capabilities of the materials.

Main Methods:

• Synthesis of coordination polymers and discrete complexes using lanthanide salts, organic ligands (HOBPT), and various solvents (H2O-MeOH, DMF).
• Structural characterization using powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction.
• Evaluation of luminescence properties and solvent selectivity through spectroscopic analysis.

Main Results:

• Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] were successfully synthesized.
• Single-crystal X-ray studies revealed distorted tricapped trigonal prism coordination geometries for Eu(3+) ions, differing in coordinating ligands (aqua/OBPT vs. DMF).
• A reversible, solvent-mediated crystal-to-crystal transformation was observed between the complexes upon exposure to water or DMF vapor.
• Complex 1 (Eu(3+) coordination polymer) demonstrated highly selective luminescence enhancement in the presence of DMF compared to other solvents.

Conclusions:

• The study successfully synthesized and characterized novel lanthanide coordination polymers and discrete complexes with distinct structural features.
• The observed crystal-to-crystal transformation highlights the dynamic nature of these materials in response to solvent stimuli.
• The selective luminescence response of Complex 1 to DMF indicates its potential application as a chemical sensor.