Pd Clusters Containing As and PPh₃ Ligands: The Structures of [Pd₉As₆ (PPh₃)₈], [Pd₂(As₂)(PPh₃)₄], and [Pd₂₀As₁₂ (PPh₃)₁₂]

Abstract

A Pd20 polyhedron all of whose surfaces are bridged by μ5‐As atoms is one distinctive feature of 1, the title compound with the highest Pd content. Compound 1 was obtained upon treatment of [PdCl2(PPh3)2] with As(SiMe3)3. Other products of the reaction were the Pd2 and Pd9 complexes mentioned in the title as well, whereby the Pd9 complex also results from the reaction of [Pd3S2Cl2(PPh3)4] with As(SiMe3)3.

Isolation of Elusive HAsAsH in a Crystalline Diuranium(IV) Complex

“…[15] The As–As bond length in 3 of 2.4102(13) Å is consistent with a single rather than double bond,[23] the latter of which tends to be about 2.2 Å,[1] and rules out the presence of an (As 2 ) unit that when trapped between two transition metals exhibits As–As bond lengths of circa 2.2–2.3 Å (see 4 below). [17, 23a, 24] When diarsenes with sterically demanding substituents are bonded to transition metals the As–As bond tends to lengthen as a result of back-bonding, for example to 2.365 Å in [(CO) 4 Fe(η 2 -As 2 Ph 2 )],[25] which suggests a significant uranium to diarsene back-bonding-type interaction in 3 (see below), which would also be consistent with a diuranium(IV) formulation. Further support for the formulation of 3 comes from the crystal structure of 4 ,[18] which crystallizes in a different crystal habit to 3 .…”

Large Semiconductor Molecules

“…The Cu(I) ions in 28 lie both within and between the phosphide layers. A similar methodology has also resulted in the formation of the shell-like copper arsenide [Cu 32 As 30 (Ph 2 PCH 2 PPh 2 ) 8 ] [57] and palladium arsenide [Pd 20 As 12 (PPh 3 ) 12 ] nanoclusters using As(SiMe 3 ) 3 [100]. 13.7…”

Electron count versus structural arrangement in clusters based on a cubic transition metal core with bridging main group elements

“…The crystal structure of Pd20(/as-As)12(PPh3)12 (4) is formed from a regular Pd8 cube, the edges of which are bridged by a/1-Pd(PPh3) unit [30]. In addition,/a 5-As bridging ligands come to complete the sheath of the central metal cube.…”

“…For instance, the ground-state electron distribution of the 124-MVE clusters Pdg(ju4-E)6(PPh3) 8 (E=As, Sb) [30,40] and Ni9(/14-E)6(PR3) s (E=As, Sb, Bi, R=Pn-Bu 3, PPh3) [41] corresponds to {120}(t2g)4(eg) °. It is different from the closed-shell configuration {120}(eg)4(tzg) ° computed for the isoelectronic 124-MVE Ni9(/a4-GeEt)6(CO)8 species.…”

“…It appears that metal-centered Mg(/24-E) 6 compounds with open-shell electronic configurations are most commonly observed. Nevertheless, these openshell configurations never lead to strong Jahn-Teller distortion [30,[39][40][41][42]. A nearly regular cubic architecture is observed for these particular clusters.…”