Exceeding Metal Capacity in Sandwich Complexes: Ligand‐Unsupported Docking of Extra Metal Moieties at Edges of a Metal Sheet Sandwich Complex

Abstract

The ligand‐unsupported accommodation of extra metal moieties in a sandwich complex is reported. Although it has been considered that the metal‐capacity of a metal sheet sandwich complex is strictly limited by the size of cyclic unsaturated hydrocarbon ligands, the M−M edge bonds in a metal sheet sandwich complex provide a ligand‐unsupported docking site for extra metal moieties, allowing expansion of metal‐capacity in sandwich complexes. The metal sheet sandwich complex [Pd4(μ4‐C8H8)(μ4‐C9H9)]+, in which the ligand‐based metal capacity is full in terms of the usage of all C=C moieties of the smaller carbocyclic ligand C8H8 in coordination, can accommodate extra M0{P(OPh)3}2 (M=Pd, Pt) moieties without coordinative assistance by either the C9H9 or the C8H8 ligand.

A sandwich-type cluster containing Ge@Pd3 planar fragment flanked by aromatic nonagermanide caps

“…This compound represents the first all-inorganic sandwich complex and promoted the growth of an interdisciplinary research area. Besides the development of ligands, the types of interlayer have also been extended to the polyatomic metal core, and the representative examples are the [Pd 3 Tr 2 Cl 3 ] − (Tr = C 7 H 7 ) and other analogous sandwich compounds containing different Pd interlayers 10 – 13 . Moreover, those complexes provide possibilities to broaden the applications of metallocenes in catalysis due to the catalytically active palladium.…”