Dual Photo-/Electrochromic Pyromellitic Diimide-Based Coordination Polymer

Area of Science:

• Materials Science
• Coordination Chemistry
• Photochemistry

Background:

• Pyromellitic diimide derivatives are explored for stimuli-responsive materials.
• Coordination polymers offer tunable properties through metal ion incorporation.
• Photochromic and electrochromic behaviors are desirable for advanced functional materials.

Purpose of the Study:

• To synthesize and characterize a novel pyromellitic diimide-based coordination polymer with zinc ions.
• To investigate the photochromic and electrochromic properties of the synthesized material.
• To understand the role of metal ions and structural modifications on photoinduced intermolecular electron transfer (PIET) and color-changing behaviors.

Main Methods:

• Synthesis of N,N'-bis(carboxymethyl)-pyromellitic diimide (H2CMPMD) and its zinc coordination polymer [Zn(CMPMD)(DMF)1.5]·0.5DMF.
• Characterization of the synthesized compounds.
• Evaluation of photochromic properties (photoresponsive rate, coloration contrast) and electrochromic behavior (color change, reversibility).

Main Results:

• The zinc coordination polymer ([Zn(CMPMD)(DMF)1.5]·0.5DMF) exhibits significantly faster photoresponsive rates and a more distinct color change compared to the free ligand.
• Metal ion incorporation and removal of coordinated DMF fine-tune interfacial electron donor-acceptor contacts, enhancing photoinduced intermolecular electron transfer (PIET) and photochromic performance.
• The coordination polymer demonstrates rapid, reversible electrochromic behavior, changing from colorless to green.

Conclusions:

• Zinc ions play a crucial role in modulating the photochromic properties of pyromellitic diimide-based materials by influencing interfacial contacts and PIET.
• Removal of coordinated solvent molecules can further enhance photochromic performance through lattice shrinkage.
• The developed coordination polymer exhibits excellent dual photo- and electrochromic properties, making it a promising candidate for stimuli-responsive functional materials and electrochromic devices.