Tunable supramolecular synthons and versatile, water-soluble building blocks for crystal engineering:

Area of Science:

• Organometallic Chemistry
• Supramolecular Chemistry
• Crystal Engineering

Background:

• Organometallic compounds serve as versatile building blocks in materials science.
• Hydrogen bonding plays a crucial role in the self-assembly of crystalline structures.
• The design of functional supramolecular architectures requires careful control over molecular interactions.

Purpose of the Study:

• To explore the potential of a water-soluble dicarboxylic cationic cobalt(III) complex as a building block for organometallic crystals.
• To investigate the hydrogen-bonding capabilities and supramolecular behavior of different protonation states of the cobalt complex.
• To synthesize and characterize novel crystalline materials incorporating the cobalt complex and various cations.

Main Methods:

• Synthesis and characterization of the dicarboxylic cationic cobalt(III) complex and its deprotonated forms.
• Crystallographic analysis to determine the structures of various salts and co-crystals.
• Investigation of hydrogen-bonding networks and cation encapsulation phenomena.

Main Results:

• The cationic dicarboxylic acid [(eta5-C5H4COOH)2Co(III)]+ (1) is a versatile precursor for organometallic crystalline edifices.
• Deprotonation yields a zwitterion (2) and a monoanion (3) with distinct hydrogen-bonding capacities.
• The zwitterion (2) acts as a supramolecular crown ether, encapsulating alkali and ammonium cations within hydrogen-bonded cages.

Conclusions:

• The protonation state of the cobalt dicarboxylic acid dictates its hydrogen-bonding behavior and supramolecular assembly.
• This cobalt complex offers a tunable platform for constructing diverse organometallic crystalline materials.
• The ability to encapsulate cations highlights potential applications in host-guest chemistry and materials design.