Temperature-dependent interchromophoric interaction in a fluorescent pyrene-based metal-organic framework

Area of Science:

• Materials Science
• Chemistry
• Optoelectronics

Background:

• Smart materials with temperature-dependent optical properties are crucial for advanced applications.
• Metal-organic frameworks (MOFs) offer tunable structures for designing functional materials.
• Thermofluorochromic materials that change color with temperature are of significant interest.

Purpose of the Study:

• To report a novel porous pyrene-based metal-organic framework, SION-7, with tuneable fluorescence emission.
• To investigate the temperature-dependent optical properties and structural changes of SION-7.
• To demonstrate the potential of SION-7 as a thermofluorochromic material for optoelectronics.

Main Methods:

• Synthesis of the porous pyrene-based metal-organic framework SION-7 ([Mg1.5(HTBAPy)(H2O)2]·3DMF).
• Variable-temperature fluorescence spectroscopy (80 K to 450 K) to observe color changes.
• Ex situ variable-temperature single-crystal X-ray diffractometry (100 K to 350 K) to study structural dynamics.

Main Results:

• SION-7 exhibits reversible thermofluorochromism, shifting from blue at low temperatures to yellow-green at high temperatures.
• The color change is attributed to temperature-dependent interchromophoric interactions between pyrene ligands.
• Structural studies reveal solvent content's impact on optical properties and ligand positioning.

Conclusions:

• SION-7 is a promising smart material with tuneable thermofluorochromic behavior.
• The material's optical properties are directly linked to its structural flexibility and temperature.
• This work represents a significant advancement in designing materials for optoelectronic applications.