Electronic Delocalization in Two and Three Dimensions: Differential Aggregation in Indium “Metalloid” Clusters

Abstract

Reduction of indium boryl precursors to give two- and three-dimensional M-M bonded networks is influenced by the choice of supporting ligand. While the unprecedented nanoscale cluster [In (boryl) ] (with an In @In @In (boryl) concentric structure), can be isolated from the potassium reduction of a bis(boryl)indium(III) chloride precursor, analogous reduction of the corresponding (benzamidinate)In Br(boryl) system gives a near-planar (and weakly aromatic) tetranuclear [In (boryl) ] system.

Intermetalloid Clusters: Molecules and Solids in a Dialogue

“…[7a] These clusters are still not completely isolated, but interconnected through In-In bonds forming two-dimensional layers of quasi-close packed clusters with additional Ni and Na atoms located between the layers.T his cluster arrangement is ah ierarchical variant [29] of the NiAs structure type in which atoms are substituted by clusters.The shell structures of Na 96 In 97 M 2 remarkably refer to the molecular core structures of the ligand-stabilized homometallic indium clusters In 19 [B(NDippCH) 2 ] 6 (Dipp = 2,6i Pr 2 C 6 H 3 )a nd [In 68 {B(NDippCH} 2 ) 12 ] À . [30] Moreover,t he intermetallic compound Na 29 (Figure 4). Considering af ormal electron transfer from the Na atoms to the network.…”

“…[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).…”

“…[15a,b, 17] At the same time,t he spatially confined dimensions of ligand-stabilized, atomically precise metal clusters bring about pronounced surface effects which create complex mixed-valence systems with unusually high surface:b ulk atom ratios and noticeable ligand effects.T hus induced directed bonding enables the formation of unprecedented structural motifs beyond the respective solid-state chemistry. 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). [19] Such deviations may in turn be understood as an inspiration for the discovery of novel element modifications,asnicely illustrated by the exemplary cases [Al 22 X 20 ]·12 L( X= Cl, Br;L= THF, THP = tetrahydropyran) [20] or [Sn 15 {N(2,6-i Pr 2 C 6 H 3 )-(SiMe 2 X)} 6 ]( X = Me,P h), [21] predicting the existence of an on-metallic b-aluminum or ab cc-structured Sn allotrope, respectively.W ea nd others aim to extend this interesting research field into the realms of heterometallic cluster chemistry,t argeting intermetalloid clusters of dissimilar metal combinations which go beyond molecular alloying of pseudo-elements or heterometallic cluster doping.Our inspiration stems from the fascinating diversity of intermetallics, particularly the Zintl and Hume-Rothery phases,w hich we wish to reconstruct and extend on the molecular level.…”

Intermetalloide Cluster: Moleküle und Festkörper im Dialog

“…[7b, 9] 68 {B-(NDippCH} 2 ) 12 ] À . [30] Auch die intermetallische Verbindung Na 29 [31] Die Vereinzelung von Clustern in Festkçrpern geht Hand in Hand mit einem idealen Ladungsübergang vom elektropositiven zum elektronegativeren Bestandteil und resultiert in einer elektrostatischen Abstoßung der hoch geladenen, intermetalloiden Einheiten, die durch die Dispersion in der Gegenionmatrix kompensiert wird. In Na 96 In 97 M 2 und Na 29 Zn 24 Sn 32 ist der teilweise Ladungstransfer bereits vollbracht, typisch fürZ intl-Phasen mit p-Block-Metallen als elektronegative Bestandteile.E ine Erweiterung des Zintl-Phasen-Prinzips auf intermetallische Verbindungen mit Übergangsmetallen wird in der bronzeartigen Verbindung Na 2.8 Cu 5 Sn 5.6 erreicht:E indimensionale doppelwandige Sn 0.6 @Cu 5 @Sn 5 -Nanorçhren mit pseudo-fünffacher Symmetrie sind durch eine abschirmende Schicht von Na-Atomen vereinzelt.…”

“…Mehrschaliger Atomkern von [Pd145 (CO) x (PEt 3 )30 ](x % 60, rechts) mit integrierten aufeinanderfolgenden Schalen. Mehrschaliger Atomkern von [Pd145 (CO) x (PEt 3 )30 ](x % 60, rechts) mit integrierten aufeinanderfolgenden Schalen.…”