Mimicking the electronic structure of endohedral triangular lanthanide clusters in “free” from host carbon cages metallofullerenes uncovers a peculiar reactivity pattern

Abstract

Highly reduced [Cp₃Ln₃(μ₂-H)₃]^−/0 (Ln = La or Lu; Cp = C₅H₅⁻) clusters “free” from host carbon cages were used as models to mimic the electronic structure of La₃@C₁₁₀ and Lu₃@C₈₀ EMFs. DFT calculations revealed that these clusters “unshielded” from host carbon cages are highly reactive, disrupting strong single H–H, H–X (X = F, Cl, Br, and I) and double O=O bonds and descending the inert N≡N triple bond up to a single N–N bond, yielding stable bicapped trinuclear [Cp₃Ln₃(μ₂-H)₃(μ₃-H)₂]⁻, [Cp₃Ln₃(μ₂-H)₃(μ₃-H)(μ₃-X)]⁻, [Cp₃Ln₃(μ₂-H)₃(μ₃-O)₂]⁻, and [Cp₃Ln₃(μ₂-H)₃(μ₃-N)₂]⁻ clusters. The calculated thermodynamics of the reactions revealed an unprecedented reactivity pattern inherent to multimetallic cooperative effect on nonclassic oxidative addition reactions which proceed by electrophilic attack of the oxidative addition (oxad) substrates at the center of the highly reduced triangular trilanthanide Ln₃ rings accompanied by “penetration” of the ring plane that cuts the strong bonds. The [Cp₃Ln₃(μ₂-H)₃]^−/0 (Ln = La or Lu) clusters, mimicking also the electronic structure of La₃@C₁₁₀ and Lu₃@C₈₀ EMFs, easily capture hydrogen, nitrogen, oxygen, and halogen atoms to yield monocapped trimetallic [Cp₃Ln₃(μ₂-H)₃(μ₃-X)] (X = H, N, O, F, Cl, Br, and I) clusters. The molecular and electronic structures of the “free” from the cage monocapped trimetallic clusters are thoroughly discussed.

Graphical Abstract

Keywords:

• Triangular La₃ clusters
• Triangular Lu₃ clusters
• Monocapped triangular lanthanide clusters
• Bicapped triangular lanthanide clusters
• DFT calculations
• Cutting strong bonds