Nanosized [Pd₅₂(CO)₃₆(PEt₃)₁₄] and [Pd₆₆(CO)₄₅(PEt₃)₁₆] Clusters Based on a Hypothetical Pd₃₈ Vertex‐Truncated ν₃ Octahedron

Abstract

Einer geht noch: Die Strukturen eines Pd52‐ und eines Pd66‐Nanoclusters haben als Gemeinsamkeit eine abgestumpfte ν‐oktaedrische Pd38‐Anordnung. Einer der 45 CO‐Liganden von [Pd66(CO)45(PEt3)16] (Pd66‐Kern abgebildet) ist überzählig. Um Platz für diesen 45. CO‐Liganden zu schaffen, gehen zwei der 44 normalen Liganden eine Umlagerung ein, bei der die Anordnung der Metallzentren nicht grundlegend verändert wird.

Syntheses, structures and properties of primarily nanosized homo/heterometallic palladium CO/PR 3 -ligated clusters

“…The two structurally related mixed CCP/HCP metal cores of Pd 52 (CO) 36 (PEt 3 ) 14 (possessing maximum and minimum metal-core diameters of 1.6 × 0.8 nm) and Pd 66 (CO) 45 (PEt 3 ) 16 (possessing a maximum diameter of 1.1 nm) contain the same central vertex-truncated CCP Pd 38 kernel (figure 7b) as that of the unknown n 3 Pd 44 octahedron (figure 7a; Mednikov et al 2005b). Although such Pd 38 and Pd 44 clusters are (as yet) unknown as distinct structural entities, analogous metal-core clusters of the congeneric Ni/Pt elements have been 7b).…”

Structures of Medium‐Sized Ruthenium Clusters: The Octahedral Motif

“…Whereas octahedral cores are well-known in ligand-stabilized metal clusters, [18] the occurrence of bulk-like fcc structures is unexpected in such small ligand-free metal clusters. This can be rationalized by an extremely tight effective pair potential which strongly penalizes bond length variations and therefore leads to bulk-like structures to minimize strain.…”

Octahedral Hexapalladium Pseudo-Td Pd6(μ3-CO)4(PEt3)6 with 80 Electron-Deficient Cluster Valence Electrons (CVEs) and a Comparison with Octahedral Hexapalladium Pseudo-C2v Pd6(μ3-CO)4(PMe3)7 with 82 CVEs: Computational Analysis and Resulting Implications

“…Structures of four octahedral-based CO/PAlk 3 -ligated homopalladium clusters with different numbers of wingtip (asymmetrically capped) Pd atoms: (a) one-capped Pd 7 (CO) 6 (PMe 3 ) 7 , shown with six CO molecules instead of seven, (b) two-capped 4 , (c) four-capped Pd 10 (CO) 12 (PAlk 3 ) 6 , where Alk = Et and Bu n , and (d) four-capped Pd 10 (CO) 14 (PBu n 3 ) 4 . Wingtip Pd atoms are shown as spheres; other designations are the same as those in Figure .…”

“…All three of the observed CO/PMe 3 -ligated octahedral-based Pd n clusters, Pd 6 ( 2 ), Pd 7 ( 3 ), and Pd 8 ( 4 ), were obtained in the presence of CO but by unrelated procedures and from different precursors . Clusters 2 and 4 were prepared from zerovalent PdL 4 and Pd 2 (dba) 3 at 50 °C and room temperature, respectively, , and 3 was obtained by reduction of the organometallic Pd­(II) complex [Pd­(η 1 ,η 3 -C 8 H 12 )­L] . Such distinctions in the synthetic routes leading to 1 – 3 strongly indicate a predominant role for kinetic factors …”

“…It should be emphasized that under a CO atmosphere in the course of two types of reactions, that is, those involving the reduction of Pd­(OAc) 2 as well as interconversions within a zerovalent Pd n (CO) x (PR 3 ) y family (with R = Et, , Bu n , , n -C 8 H 17 , n -C 12 H 25 , Ph, C 6 H 4 - p -Me, and C 6 H 4 - p -OMe), none of the intermediate Pd n nuclearities between n = 4 and 10 were observed . − However, reactions involving the use of the PMe 3 ligand gave rise to new CO/PR 3 -ligated clusters that filled in this intermediate Pd n gap (between n = 4 and 10), namely, Pd 6 (CO) 4 (PMe 3 ) 7 ( 2 ), Pd 7 (CO) 7? (PMe 3 ) 7 ( 3 ), and Pd 8 (CO) 8 (PMe 3 ) 7 ( 4 ) …”