Amalgamating metalloligands with coordination networks.

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Organometallic Chemistry

Background:

• Schiff base ligands with O(4)-cavities are known to coordinate metal ions.
• The study investigates the reactivity of these complexes with mercury salts.

Purpose of the Study:

• To explore the coordination behavior of Schiff base complexes with mercury salts.
• To investigate the potential for diastereoselectivity and C-mercuration reactions.

Main Methods:

• Single crystal X-ray diffraction
• Coordination of mercury salts (HgBr2, Hg(CN)2, Hg(NO3)2·H2O) to copper and nickel Schiff base complexes
• Structural analysis of the resulting complexes and coordination polymers

Main Results:

• Complexes of the type [Cu{(R,R)-}HgBr2] and [Ni{(R,R)-}HgBr2] were formed, exhibiting no diastereoselectivity in helical twist.
• Crystallization revealed co-existing P- and M-helical enantiomers in the asymmetric unit.
• Reaction with excess mercury(II) nitrate resulted in C-mercuration of the Schiff base ligand and formation of a 2D coordination polymer.

Conclusions:

• The O(4)-cavity readily binds mercury salts, but the helical twist of the Schiff base ligand lacks diastereoselectivity.
• Direct C-mercuration of coordinated Schiff base ligands is a significant reaction pathway with mercury(II) nitrate, leading to extended network structures.