A new two-dimensional anionic cadmium(II) polymer constructed through thiocyanate coordination bridges

Area of Science:

• Coordination Chemistry
• Materials Science
• Crystallography

Background:

• Coordination polymers offer tunable properties based on metal-ligand interactions.
• Thiocyanate ligands are versatile linkers in constructing complex inorganic structures.
• Understanding supramolecular assembly is key to designing novel materials.

Purpose of the Study:

• To synthesize and characterize a new cadmium-thiocyanate coordination polymer.
• To investigate the structural features and bonding interactions within the complex.
• To explore the formation of 2D and supramolecular networks.

Main Methods:

• Synthesis via reaction of cadmium thiocyanate and 4-(dimethylamino)pyridine hydrochloride in aqueous solution.
• Single crystal X-ray diffraction analysis to determine the crystal structure.
• Analysis of coordination environment, ligand roles, and intermolecular interactions (hydrogen bonding, π-π stacking).

Main Results:

• A novel cadmium-thiocyanate complex, poly[4-(dimethylamino)pyridin-1-ium [di-μ-thiocyanato-κ(2)N:S;κ(2)S:N-thiocyanato-κN-cadmium(II)]], {(C7H11N2)[Cd(NCS)3]}n, was successfully synthesized.
• Each Cd(II) ion exhibits square-pyramidal coordination involving five thiocyanate ligands, with four acting as bridges.
• The structure is built from [Cd2(NCS)2] units linked by other thiocyanate ligands, forming a 2D network stabilized by N-H···S hydrogen bonds and π-π stacking.

Conclusions:

• The study presents a new cadmium-thiocyanate coordination polymer with a well-defined 2D network structure.
• Thiocyanate ligands play dual roles in forming building blocks and linking them via hydrogen bonds.
• Supramolecular assembly is driven by a combination of coordination, hydrogen bonding, and π-π interactions, leading to the observed network architecture.