Der Mackay‐Cluster [Cu₄₃Al₁₂](Cp*)₁₂: Ein offenschaliges 67‐Elektronen‐Superatom mit metallähnlicher elektronischer Struktur

Abstract

Der paramagnetischeC luster [Cu 43 Al 12 ](Cp*) 12 entsteht bei der Reaktion von [CuMes] 5 mit [AlCp*] 4 (Cp* = h 5 -C 5 Me 5 ;M es = Mesityl). Dieser ausschließlich durchK ohlenwasserstoff-Liganden stabilisierte "magische" Cluster mit 55 Atomen im Clusterkern weist eine ummantelte Ikosaeder-Struktur des Mackay-Typs auf.D ie Superatomkonfiguration von 67 Elektronen und offener Valenzschale ist einzigartig, wobei drei ungepaarte Elektronen schwacha ntibindende Jellium-Zustände besetzen. Diese Situation deutet auf die Bildung eines Leitungsbands hin, was durch die Temperaturunabhängigkeit des Magnetismus bestätigt wird.D ie sterische Abschirmung durch 12 Cp*-Liganden unterdrückt die intrinsische polyradikalische Reaktivitätdes Cu 43 Al 12 -Kerns.

Observation of Non‐FCC Copper in Alkynyl‐Protected Cu53Nanoclusters

“…Also, there is no linear variation of magnetic susceptibility (between 5 K and 300 K) or significant magnetic moment change in magnetic field up to 20 000 Oe on superconducting quantum interference device (SQUID; Supporting Information, Figures S13, S14). These results indicate Cu 53 has a closed‐shell electronic configuration with a non‐magic electron count …”

Intermetalloid Clusters: Molecules and Solids in a Dialogue

“…[105] An even larger,n ovel NiGa cluster [Ni 8 Ga 6 ](Cp*) 6 with a > b and a + b @ n is obtained in the reaction of [Ni(cdt)] (cdt = 1,5,9-Cyclododecatrien) with GaCp* proceeding via the isolable,a nd fully characterized intermediate [Ni(cdt)-(GaCp*)]. [107] Despite the unusually high degree of disorder of the central nickel core which precluded ar eliable determination of its core geometry,t he overall Ni 8 Ga 6 core structure was found to be (distantly) related to structural motifs frequently observed in binary NiGa phases.Q uite similarly,t he structure of the first truly intermetalloid example of acluster [M a E b ](Cp*) n with a + b @ n,[Cu 43 Al 12 ]-(Cp*) 12 (Figure 15), [107] features aM ackay-type two-shell icosahedral core,astructural motif which is commonly found in quasicrystalline phases of related compositions, like ternary copper aluminide systems. [108] Quantum chemical calculations revealed the exceptional open-shell superatomic electron configuration of the system with an unusually high electron count of 67 electrons,w hereat the high reactivity associated with such an electronic configuration was anticipated to be contained within the spherical capsule of the twelve,s terically shielding Cp* ligands.…”

“…[95] Angewandte Chemie Reviews of the compound with benzonitrile further revealed striking resemblance of its surface reactivity to catalytically relevant semi-hydrogenation reactions at Hume-Rothery nanophases, like Fe 4 Al 13 ,o rb inary PdGa-and NiGa-phases. [107] Despite the unusually high degree of disorder of the central nickel core which precluded ar eliable determination of its core geometry,t he overall Ni 8 Ga 6 core structure was found to be (distantly) related to structural motifs frequently observed in binary NiGa phases.Q uite similarly,t he structure of the first truly intermetalloid example of acluster [M a E b ](Cp*) n with a + b @ n,[Cu 43 Al 12 ]-(Cp*) 12 (Figure 15), [107] features aM ackay-type two-shell icosahedral core,astructural motif which is commonly found in quasicrystalline phases of related compositions, like ternary copper aluminide systems. [105] An even larger,n ovel NiGa cluster [Ni 8 Ga 6 ](Cp*) 6 with a > b and a + b @ n is obtained in the reaction of [Ni(cdt)] (cdt = 1,5,9-Cyclododecatrien) with GaCp* proceeding via the isolable,a nd fully characterized intermediate [Ni(cdt)-(GaCp*)].…”

“…Cu orange, Al atoms blue, Catoms gray.Atom shells are shown as orange and blue polyhedra [107]. Cu orange, Al atoms blue, Catoms gray.Atom shells are shown as orange and blue polyhedra [107].…”

“…The neutral cluster is found to adopt the (t 2u ) 2 (a g ) 1 open-shell configuration [107]. The neutral cluster is found to adopt the (t 2u ) 2 (a g ) 1 open-shell configuration [107].…”