Isolation and Structural Characterization of a Mackay 55-Metal-Atom Two-Shell Icosahedron of Pseudo-I_h Symmetry, Pd₅₅L₁₂(μ₃-CO)₂₀ (L = PR₃, R = Isopropyl): Comparative Analysis with Interior Two-Shell Icosahedral Geometries in Capped Three-Shell Pd₁₄₅, Pt-Centered Four-Shell Pd–Pt M₁₆₅, and Four-Shell Au₁₃₃ Nanoclusters

Abstract

We present the first successful isolation and crystallographic characterization of a Mackay 55-metal-atom two-shell icosahedron, Pd55L12(μ3-CO)20 (L = PPr(i)3) (1). Its two-shell icosahedron of pseudo-Ih symmetry (without isopropyl substituents) enables a structural/bonding comparison with interior 55-metal-atom two-shell icosahedral geometries observed within the multi-shell capped 145-metal-atom three-shell Pd145(CO)72(PEt3)30 and 165-metal-atom four-shell Pt-centered (μ12-Pt)Pd164-xPtx(CO)72(PPh3)20 (x ≈ 7) nanoclusters, and within the recently reported four-shell Au133(SC6H4-p-Bu(t))52 nanocluster. DFT calculations carried out on a Pd55(CO)20(PH3)12 model analogue, with triisopropyl phosphine substituents replaced by H atoms, revealed a positive +0.84 e charge for the entire Pd55 core, with a highly positive second-shell Pd42 surface of +1.93 e.

An Atomically Precise Alkynyl‐Protected PtAg42 Superatom Nanocluster and Its Structural Implications

“…A recent report on Au 19 Cu 30 demonstrated an icosidodecahedral Cu 30 shell . We can also recognize an icosidodecahedral Pd 30 shell in a recently determined Mackay icosahedral Pd 55 cluster, whose metallic kernel shares similar structure with Au 55 ‐MI . The Ag 30 shell in 1 , together with the above‐mentioned Au 30 , Cu 30 , and Pd 30 shells, makes up an universal icosidodecahedral M 30 family and indicates the generalization of icosidodecahedral M 30 shells.…”

The Mackay‐Type Cluster [Cu43Al12](Cp*)12: Open‐Shell 67‐Electron Superatom with Emerging Metal‐Like Electronic Structure

“…Accordingly,S chnçckels cluster [Al 50 (Cp*) 12 ], discovered in 2004, can be described as aC p*-ligated complex of the homometallic [Al 50 ] 12+ superatom with a1 38-electron closed shell. Its formula can be written as [Al 38 ](AlCp*) 12 ,l eading to the heuristic view of an Al 38 core protected by twelve 2e À donating AlCp* ligands.A ccord-ingly,w ea nticipated that other metal cluster cores [M a ]m ay also be stabilized by AlCp* to yield heterometallic superatom complexes. Its formula can be written as [Al 38 ](AlCp*) 12 ,l eading to the heuristic view of an Al 38 core protected by twelve 2e À donating AlCp* ligands.A ccord-ingly,w ea nticipated that other metal cluster cores [M a ]m ay also be stabilized by AlCp* to yield heterometallic superatom complexes.…”

“…[7][8][9][10][11] One of our long term targets has been obtaining large,truly intermetalloid clusters [TM a E b ](L c )w ith a + b @ c. Herein, we report success in this research enterprise (Scheme 1, Figure 1). Thetitle compound, [Cu 43 (AlCp*) 12 ] = [Cu 43 Al 12 ](Cp*) 12 (1), is the very first example of al igated heterometallic Mackay-type M 55 magic atom-number cluster with ap erfect two-shell icosahedral structure.M agnetic data and analysis at the DFT level of theory reveal the unique electronic structure of the cluster 5 in benzene at 78 8 8Creproducibly yields analytically pure 1 as ab lack crystalline solid, albeit in low yields of 10-17 %( Scheme 1). Thec ompound is highly air and moisture sensitive;t he isolated crystals are pyrophoric upon exposure to air.…”

Intermetalloid Clusters: Molecules and Solids in a Dialogue

“…[15] These include metal species like thiolateligated Au n (SR) x with fcc kernels (e.g.for n = 28, 36, 44, …), [16] as well as metal clusters of group 13 and 14 elements mimicking cut-outs of their respective element modifications. To name just one example,m ulti-shell core structures based on icosahedral Mackay-type packing motifs,are observed for the polynuclear palladium kernels of [Pd 55 (P i Pr 3 ) 12 (CO) 20 ], [18] or the cluster giants [Pd 145 (CO) x (PEt 3 ) 30 ]( x % 60, Figure 2) and [(m 12 -Pt)Pd (164Àx) Pt x (CO) 72 (PPh 3 ) 20 ](x % 7). To name just one example,m ulti-shell core structures based on icosahedral Mackay-type packing motifs,are observed for the polynuclear palladium kernels of [Pd 55 (P i Pr 3 ) 12 (CO) 20 ], [18] or the cluster giants [Pd 145 (CO) x (PEt 3 ) 30 ]( x % 60, Figure 2) and [(m 12 -Pt)Pd (164Àx) Pt x (CO) 72 (PPh 3 ) 20 ](x % 7).…”