Formation of Metallic Polyferrocene Chains under Pressure

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Chemistry

Background:

• Ferrocene (Fc), a stable organometallic compound, is known for its unique electronic and structural properties.
• Understanding pressure-induced structural transformations is crucial for designing novel materials with tailored properties.

Purpose of the Study:

• To investigate the effect of high pressure on the structural reorganization of ferrocene.
• To explore the formation of new phases and their properties under extreme conditions.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Evolutionary crystal structure prediction algorithms (USPEX code) were utilized.
• Pressure-dependent Raman spectroscopy was performed to validate theoretical predictions.

Main Results:

• Above 220 GPa, ferrocene undergoes pressure-induced polymerization (PIP) to form quasi-one-dimensional chains of polyferrocene (p-Fc).
• Polymerization leads to distortions in cyclopentadiene rings and the formation of C-C sigma bonds.
• Polyferrocene exhibits a reduced band gap, metallic states, and a significantly increased bulk modulus compared to ferrocene.

Conclusions:

• High pressure induces a novel polymerization pathway in ferrocene, creating a metallic and rigid polymer.
• Polyferrocene presents a promising candidate for applications in high-pressure synthesis and advanced materials.