Rare-earth metal ethylene and ethyne complexes

Area of Science:

• Organometallic Chemistry
• Rare-Earth Chemistry
• Coordination Chemistry

Background:

• Synthesis of homometallic and heterobimetallic rare-earth ethyl complexes is crucial for understanding their reactivity.
• Exploration of novel bonding motifs and reaction mechanisms involving rare-earth elements and organoaluminum compounds is an active research area.

Purpose of the Study:

• To synthesize and characterize novel homometallic and heterobimetallic rare-earth ethyl complexes.
• To investigate the formation of an unprecedented rare-earth ethyne complex and elucidate its bonding and mechanism.
• To explore the reactivity of rare-earth precursors with triethylaluminum.

Main Methods:

• Synthesis of rare-earth ethyl complexes via reaction of LLn(CH2C6H4NMe2-o)2 with AlEt3 in toluene.
• Isolation and characterization of homometallic, heterobimetallic, ethyne, and ethylene complexes.
• Density Functional Theory (DFT) calculations for mechanism studies.
• Natural Bond Orbital (NBO) analysis for bonding nature investigation.

Main Results:

• Successful synthesis of homometallic [LLn(μ2-η1:η2-Et)(Et)]2 and heterobimetallic LLn(Et)(μ2-η1:η2-Et)(μ2-η1-Et)(AlEt2) rare-earth ethyl complexes.
• Discovery of an unprecedented rare-earth ethyne complex [LY(μ2-η1-Et)2(AlEt)]2(μ4-η1:η1:η2:η2-C2H2) containing a [C2H2]4- unit.
• Identification of a non-Cp rare-earth ethylene complex LY(μ3-η1:η1:η2-C2H4)[(μ2-η1-Et)(AlEt2)(μ2-η1-Et)2(AlEt)] and its intermediate Y/Al ethyl complex.

Conclusions:

• The reaction of rare-earth precursors with triethylaluminum offers a versatile route to diverse organometallic complexes.
• The unprecedented ethyne complex highlights novel coordination modes and reactivity of rare-earth elements.
• Computational studies provide valuable insights into the mechanistic pathways and electronic structure of these complexes.