Formal Nickelate(-I) Complexes Supported by Group 13 Ions

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Nickel complexes are crucial in catalysis and materials science.
• Exploration of low-valent nickel species offers unique reactivity.
• Group 13 elements (e.g., aluminum, gallium) are increasingly incorporated into novel inorganic frameworks.

Purpose of the Study:

• To synthesize and characterize novel nickelate(-I) complexes featuring Group 13 metalloligands.
• To investigate the electronic structure and bonding in these reduced nickel species.
• To understand the impact of one-electron reduction on nickel-metal interactions.

Main Methods:

• Synthesis of nickelate(-I) complexes via one-electron reduction of Ni(0) precursors.
• Single-crystal X-ray diffraction for structural determination.
• Electron Paramagnetic Resonance (EPR) spectroscopy for spin characterization.
• Quantum chemical calculations for electronic structure analysis.

Main Results:

• Isolation of stable 17-electron nickelate(-I) complexes with aluminum and gallium.
• Experimental and computational evidence for a strengthened Ni-M bond after reduction.
• Observation of delocalized unpaired spin density across both Ni and M atoms.
• Identification of an unusual electronic configuration with three valence electrons in two σ-bonding orbitals.

Conclusions:

• The study successfully synthesized and characterized novel nickelate(-I) complexes with Group 13 elements.
• One-electron reduction leads to significant changes in bonding and electronic structure, including Ni-M bond strengthening and spin delocalization.
• The findings reveal an intriguing electronic configuration, expanding the understanding of bonding in low-valent transition metal compounds.