Octapalladium Strings Trap C and C Fullerenes Affording Metal-Chain-Wired Bucky Balls.

Reactions of Pd strings supported by meso-Ph PCH P(Ph)CH P(Ph)CH PPh (meso-dpmppm) ligands, [Pd (meso-dpmppm) (L) ] (L=CH CN (1), XylNC (2)) with C resulted in the exclusive formation of unprecedented metal-chain-wired C bucky balls, [{Pd (meso-dpmppm) (L)} (C )] (L=CH CN (11), XylNC (12)), in which a C fullerene is trapped in the central Pd-Pd junction, as unambiguously established by spectroscopic, X-ray crystallographic, and theoretical techniques. The similar reaction of Pd strings supported by rac-dpmppm, [Pd (rac-dpmppm) (CH CN) ] (3) also afforded a racemic mixture of [{Pd ((R*,R*)-dpmppm) (CH CN)} (C )] (13) without scrambling the Pd fragments with (R,R)- and (S,S)-dpmppm ligands. Consequently, those of enantiopure chiral Pd strings, [Pd ((R*,R*)-dpmppm) (CH CN) ] , certainly afforded chiral bucky balls of [{Pd ((R*,R*)-dpmppm) (CH CN)} (C )] (13 and 13 ), that exhibit mirror-image circular dichroism spectra. The reactions of 1 and 2 were also applied for trapping a C fullerene to give 2 : 1 adducts of [{Pd (meso-dpmppm) (L)} (C )] (L=CH CN (21), XylNC (22)). These results provide useful information for creating a platform to develop dimensionally and chirality controlled metal-carbon nanocomposite materials.