Aromatization of fulvene by complexation with lithium

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Organic Chemistry

Background:

• Fulvene molecules are non-aromatic hydrocarbons.
• Understanding interactions with alkali metals is crucial for materials science.

Purpose of the Study:

• Investigate the electronic and aromatic changes in fulvene upon complexation with a lithium atom.
• Quantify the binding energy and aromatic character of the Li-fulvene complex.

Main Methods:

• Density Functional Theory (DFT) calculations using the B3LYP/6-311++G(d,p) level of theory.
• Analysis of binding energy, geometry, and aromaticity indices (HOMA, NICS).
• Visualization of π-electron current density using ipsocentric calculations.

Main Results:

• Formation of a Li-fulvene complex with a binding energy of 41 kcal/mol.
• The complex exhibits significant ion-pair character.
• Fulvene moiety develops a delocalized aromatic π system, confirmed by HOMA and NICS values (-11 ppm).
• Strong diatropic ring current observed in the fulvene ring.

Conclusions:

• Lithium atom complexation induces aromaticity in the fulvene molecule.
• The interaction transforms fulvene into an aromatic system with ion-pair characteristics.
• Computational methods effectively characterize the electronic and aromatic modifications.