Humidity-Induced Structural Transformation in Pseudopolymorph Coordination Polymers.

Area of Science:

• Coordination Chemistry
• Materials Science
• Crystallography

Background:

• Schiff base ligands are versatile building blocks for coordination polymers.
• Pseudopolymorphism in coordination compounds can lead to diverse structural motifs.
• Solvent and humidity play critical roles in crystal engineering.

Purpose of the Study:

• To synthesize novel cadmium coordination polymers using a Schiff base ligand.
• To investigate the structural transformations and pseudopolymorphism of these compounds.
• To elucidate the influence of solvent systems and humidity on structural motifs.

Main Methods:

• Synthesis of coordination polymers via solvothermal methods.
• Single-crystal and powder X-ray diffraction for structural characterization.
• Thermogravimetric analysis to assess thermal stability.

Main Results:

• Three cadmium coordination polymers, {[CdL(OAc)2](C2H5OH)} (1), {[CdL(OAc)2](CH3CN)} (2), and [CdL(OAc)2(H2O)] (3), were successfully synthesized.
• Compounds 1 and 2 (1D ladder) transformed to compound 3 (1D linear) via water absorption.
• Compound 3 transformed back to compound 1 through dissolution-recrystallization, demonstrating structural reversibility.

Conclusions:

• Solvents and humidity are crucial factors in controlling the formation of pseudopolymorphs.
• The study highlights a rare case of solvent-induced and humidity-driven structural transformation in coordination polymers.
• Understanding these transformations is key for designing materials with specific structural properties.