Chromium-Lanthanide Complexes Containing the Cr═P═Cr Fragment: Synthesis, Characterization, and Computational Study

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Synthesis and characterization of novel heterometallic complexes are crucial for understanding complex bonding and electronic structures.
• Lanthanide and transition metal complexes offer diverse applications due to their unique electronic and magnetic properties.

Purpose of the Study:

• To synthesize and characterize novel heterometallic complexes featuring lanthanide and chromium elements.
• To elucidate the structural diversity and electronic properties of these new compounds, particularly the origin of observed 31P NMR shifts.

Main Methods:

• Synthesis of heterometallic complexes via reactions involving lanthanide precursors and a unique P2-bridged chromium complex.
• Structural characterization using single-crystal X-ray diffraction analysis.
• Spectroscopic analysis (31P NMR) and quantum chemical calculations to understand electronic structure and chemical shifts.

Main Results:

• Successfully synthesized heterometallic complexes [Cp*2Ln(μ-CO)2{Cr2(μ-P)Cp2(CO)2}] for Yb (1), Sm (2), and Y (3).
• Determined molecular and polymeric structures for compounds 1-3, revealing a unique {((CO)2CpCr═P═CrCp(CO)2)}- unit linked to Ln3+ ions.
• Observed significant downfield shifts in 31P NMR, attributed by quantum chemical calculations to the anisotropic effect of Cr═P double bonds.

Conclusions:

• The study reports the successful synthesis and structural elucidation of novel heterometallic lanthanide-chromium complexes.
• The unique electronic structure, particularly the high downfield 31P NMR shifts, is explained by the anisotropic effects of Cr═P double bonds.
• These findings contribute to the understanding of bonding and electronic properties in complex organometallic systems.