Structurally diverse macrocycle co-crystals for solid-state luminescence modulation.

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Organic Electronics

Background:

• Organic co-crystals are key for functional materials, but traditional packing limits diversity.
• Existing methods often result in segregated or mixed stacking, hindering novel properties.

Purpose of the Study:

• To explore structural and functional diversity in organic co-crystals.
• To investigate tunable emission properties based on varying stoichiometric ratios and packing modes.

Main Methods:

• Synthesized three sets of macrocycle co-crystals with identical components but different ratios (2:1, 1:1, 2:3).
• Utilized triangular pyrene-macrocycle and 1,2,4,5-tetracyanobenzene with charge-transfer interactions.
• Performed X-ray diffraction analysis and density functional theory calculations.

Main Results:

• Achieved distinct molecular packing modes and tunable emission across yellow, orange, and red spectra (575-635 nm).
• Demonstrated a direct correlation between stoichiometric ratios, packing, and luminescence properties.
• Identified charge-transfer transition states as the origin of red-shifted luminescence.

Conclusions:

• Novel organic co-crystals with tunable luminescence were successfully fabricated.
• The study highlights the potential of controlling co-crystal stoichiometry for diverse material properties.
• Findings provide insights into superstructure-property relationships for advanced organic functional materials.