Designed topology and site-selective metal composition in tetranuclear [MM'...M'M] linear complexes

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Quantum Computing

Background:

• The ligand 1,3-bis[3-oxo-3-(2-hydroxyphenyl)propionyl]benzene (H(4)L) facilitates the assembly of transition metals.
• Tetranuclear linear molecules with [MMMM] topology are of interest for their structural and magnetic properties.

Purpose of the Study:

• To synthesize and characterize novel tetranuclear metal complexes.
• To explore the magnetic properties of these complexes.
• To investigate the potential of a heterometallic complex as a two-qubit quantum gate.

Main Methods:

• Synthesis of metal complexes using H(4)L ligand and M(II) salts (M=Ni, Co, Cu).
• Crystallographic characterization of novel complexes [Co(4)L(2)(py)(6)] and [Na(py)(2)][Cu(4)L(2)(py)(4)](ClO(4)).
• Magnetic susceptibility measurements to determine spin ground states.

Main Results:

• Successful synthesis of tetranuclear complexes with [MMMM] topology.
• Characterization of novel cobalt and sodium-copper complexes.
• Demonstration of antiferromagnetic interactions in complexes 1, 2, and 3, leading to S=0 spin ground states.
• Synthesis of heterometallic complex [Cu(2)Ni(2)L(2)(py)(6)] (4) with two quasi-independent S=1/2 moieties.

Conclusions:

• The ligand H(4)L effectively directs the formation of tetranuclear metal complexes.
• Complex 4 exhibits properties suitable for a prototype two-qubit quantum gate.
• The study highlights the tunability of coordination geometries and magnetic interactions in polynuclear complexes.