Open-framework copper adeninate compounds with three-dimensional microchannels tailored by aliphatic monocarboxylic...

Area of Science:

• Materials Science
• Coordination Chemistry
• Nanotechnology

Background:

• Coordination polymers are crystalline materials constructed from metal ions and organic ligands.
• Adenine, a fundamental nucleobase, offers unique coordination sites for metal ions.
• Monocarboxylic acids can act as versatile bridging ligands in coordination polymer synthesis.

Purpose of the Study:

• To synthesize and characterize a series of isostructural copper(II) coordination polymers incorporating adenine and varying monocarboxylic acids.
• To investigate the structural features and porosity of these novel materials.
• To assess the potential of these compounds for gas adsorption applications.

Main Methods:

• Single-crystal X-ray diffraction analysis was employed to determine the precise crystal structures.
• Gas adsorption measurements were conducted to evaluate the porosity of the synthesized compounds.
• The preparation involved reactions between copper(II) salts, adenine, and different monocarboxylic acids.

Main Results:

• Isostructural copper(II) coordination polymers with the general formula [Cu(2)(μ(3)-ade)(2)(μ(2)-OOC(CH(2))(n)CH(3))(2)]·xH(2)O (n=0-5) were successfully synthesized.
• X-ray analysis revealed a 3D covalent network structure where copper(II) centers are bridged by adenine and carboxylate ligands.
• The pores within the network are decorated by the Watson-Crick faces of adenine and can trap water molecules.
• Gas adsorption studies confirmed the tunable permanent porosity of the guest-free compounds.

Conclusions:

• The study successfully demonstrates the synthesis of a new series of adenine-based copper(II) coordination polymers.
• The materials exhibit tunable porosity, attributed to the modular nature of the carboxylic acid ligands.
• These coordination polymers show potential for applications in gas storage and separation due to their permanent porosity.