Synthesis and Properties of a Through-Space Interacting Diradicaloid

Area of Science:

• Organic Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Understanding diradicaloid electronic structures is key to their unique functional properties.
• Phenalenyl-based systems are of interest due to their radical characteristics.

Purpose of the Study:

• To synthesize and characterize a novel diradicaloid.
• To investigate the electronic structure and bonding interactions within the diradicaloid.
• To determine the diradical character and magnetic coupling of the synthesized compound.

Main Methods:

• Synthesis and characterization of the diradicaloid.
• Physicochemical studies including 1H NMR, electronic absorption, cyclic voltammetry, SQUID, and ESR.
• Quantum chemical calculations, specifically Density Functional Theory (DFT), to analyze electronic structure and bonding.

Main Results:

• Successful synthesis and characterization of a diradicaloid with two coupled phenalenyl radical sites.
• Experimental and computational evidence confirms antiferromagnetic coupling via through-space interaction.
• The diradicaloid exhibits significant singlet diradical character, with the singlet state lower in energy than the triplet state.
• DFT calculations show small spatial overlap between the singly occupied molecular orbitals (SOMOs) facilitating efficient electron exchange.

Conclusions:

• The synthesized diradicaloid possesses singlet diradical character driven by through-space antiferromagnetic coupling.
• The electronic structure and bonding interactions are well-described by DFT, highlighting the role of SOMO overlap.
• This work provides insights into the fundamental electronic properties of diradicaloids and their potential applications.