title: Bond formation and coupling between germyl and bridging germylene ligands in dinuclear palladium(I) complexes.
abstract: The dinuclear palladium(I) complexes [L(Ar2 HGe)Pd(μ-GeAr2 )2 Pd(GeHAr2 )L] (Ar=Ph, p-Tol; L=PMe3 , tBuNC) contain terminal germyl and bridging germylene ligands with the experimentally observed Ge⋅⋅⋅Ge bond lengths of 2.8263(4) Å (L=PMe3 ) and 2.928(1) Å (L=tBuNC), which are close to the longest Ge-Ge bond reported to date [2.714(1) Å]. Significant Ge⋅⋅⋅Ge interactions between the germylene and germyl ligands (PMe3 complexes > tBuNC complexes) are supported by DFT calculations, Wiberg bond indices (WBI), and natural bond orbital (NBO) analyses. Exchanging tBuNC for PMe3 ligands increases the Ge⋅⋅⋅Ge interaction, and simultaneously activates two Pd-Ge bonds. Adding the chelating diphosphine 1,2-bis(diethylphosphino)ethane (depe) to the PMe3 complexes results in the intramolecular coupling of germyl and germylene ligands followed by extrusion of a digermane.
authors: Chemical Resources Laboratory, Tokyo Institute of Technology, 4259-R1-3 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan).
authors: Makoto
authors: M
authors: Tanabe
authors: Shumpei
authors: S
authors: Omine
authors: Naoko
authors: N
authors: Ishikawa
authors: Kohtaro
authors: K
authors: Osakada
authors: Yoshihiro
authors: Y
authors: Hayashi
authors: Susumu
authors: S
authors: Kawauchi
keywords: P ligands; bridging ligands; density functional calculations; germanium; ligand effects