Modulating Solid-State Photocycloaddition Kinetics via Ligand Substituents and Crystal Structures in One-Dimensional...

Area of Science:

• Materials Science
• Chemical Kinetics
• Solid-State Chemistry

Background:

• Investigating solid-state reaction kinetics is crucial for materials design but faces challenges like limited mobility and complex nucleation.
• One-dimensional crystalline coordination polymers (CPs) offer ordered platforms to overcome these limitations.

Purpose of the Study:

• To investigate the kinetics of [2 + 2] photocycloaddition reactions within coordination polymers.
• To determine how substituent electronegativity and crystal morphology affect reaction rates.

Main Methods:

• Utilized nuclear magnetic resonance (NMR), fluorescence spectroscopy, and laser scanning confocal microscopy.
• Employed theoretical calculations to analyze reaction kinetics.
• Compared reaction rates in single-crystal versus stacked CPs.

Main Results:

• Electronegativity of carboxylate ligand substituents directly correlates with photocycloaddition reaction rates; higher electronegativity accelerates kinetics.
• Single-crystal CPs demonstrate significantly faster reaction rates than stacked crystals.
• Uniform light penetration and reduced spatial inhomogeneity in single crystals enhance reaction efficiency.

Conclusions:

• Coordination polymers serve as effective model systems for studying heterogeneous reaction kinetics.
• Substituent effects and crystal architecture are key factors in optimizing solid-state olefin reactivity.
• This work provides a framework for designing functional materials with controlled solid-state reactivity.