Highly Symmetrical Palladium Cluster Complexes with Either Anticuboctahedral or Cuboctahedral Pd₁₃ Core: Theoretical...

Area of Science:

• Inorganic Chemistry
• Materials Science
• Computational Chemistry

Background:

• Determining the factors that dictate the symmetry of metal nanocluster structures is a key challenge in inorganic chemistry.
• The palladium-13 ([Pd13]) core complex [Pd13(μ-Cl)3(μ4-C16H16)6]+ (Anti-μ) exhibits an anticuboctahedral structure, contrasting with the cuboctahedral core of [Pd13(μ4-C7H7)6]2+.

Purpose of the Study:

• To investigate the factors controlling the structural symmetry of palladium-13 nanocluster complexes.
• To elucidate the relationship between ligand coordination, steric effects, and the resulting core symmetry in metal nanoclusters.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to analyze the stability of various [Pd13(μ-Cl)3(ligand)6]+ isomers.
• Interaction energies (Eint) between the [Pd13(μ-Cl)3]+ core and the (C16H16)6 ligand shell were calculated and compared.

Main Results:

• The stability of the complexes is primarily determined by the interaction energy (Eint) between the [Pd13(μ-Cl)3]+ core and the (C16H16)6 ligand shell, rather than the individual stabilities of the core and ligand shell.
• The μ4-C16H16 coordination bond is stronger than μ2- and μ3-coordination bonds, resulting in a higher Eint for the Anti-μ isomer.
• Steric repulsion between the C16H16 ligand and the μ-Cl ligand prevents the formation of stable μ4-C16H16 coordination bonds in the cuboctahedral isomer [Pd13(μ-Cl)3(μ4-C16H16)6]+.

Conclusions:

• The anticuboctahedral symmetry of [Pd13(μ-Cl)3(μ4-C16H16)6]+ arises from strong μ4-C16H16 coordination bonds without steric hindrance.
• An icosahedral Pd13 core is unfavorable due to the absence of a Pd4 plane necessary for μ4 coordination.
• Ligand coordination mode and steric factors are crucial in determining the final structure and stability of metal nanocluster complexes.