Coordination of cyclic unsaturated hydrocarbons to transition metal generally gives bis-ligated sandwich complexes, which are a fundamental class of organometallic compounds. This sandwich structure may be extended to a higher-order three-dimensional one when more than two carbocyclic ligands surround an agglomerate of many transition metal atoms. Here, we report synthesis of three-dimensional sandwich nanocube compounds containing a close-packed transition metal cluster core. Reduction of a [Pd(μ-CH)] with tetraarylborate under neat conditions afforded [Pd(μ-CH)] containing a cuboctahedral Pd core with an octahedral ligand-shell.

We report reductive dimerization of mixed metal Pd2Pt or PdPt2 sandwich complexes. The dimerization occurs through selective Pt–Pt bond formation, and the PdPt2 dimer has a unique axially chiral structure derived from the heterometal arrangement.