Flexible Building Blocks for Transition Metal Early−Late Chemistry. Synthesis of Heterobimetallic Tetranuclear Metallomacrocycles

The reaction of LiOCH2PPh2 with the metallocene compounds [Cp2MCl2] yields the
metallodiphosphines [Cp2M(OCH2PPh2)2] (M = Ti (1), Zr (2)). Compound 2 has also been
prepared by reaction of HOCH2PPh2 with [Cp2ZrMe2], although the reaction with [Cptt2ZrMe2] (Cptt = η5-1,3-di-tert-butylcyclopentadienyl) stops at the complex [Cptt2ZrMe(OCH2PPh2)] (3). The mononuclear late transition metal complexes containing (diphenylphosphanyl)methanol ligands, cis-[M(cod)(Ph2PCH2OH)2]BF4 (M = Rh (4), Ir (5)) and cis-[Pt(p-tolyl)2(Ph2PCH2OH)2] (6), have been prepared by reaction of [M(cod)(NCCH3)2]BF4 and [Pt(μ-SEt2)(p-tolyl)2]2 with HOCH2PPh2. The reaction of the metallodiphosphines 1 and 2 with
the compounds [M(diolef)(NCCH3)2]BF4 (M = Rh, Ir) afforded the tetranuclear d0−d8 early−late heterobimetallic (ELHB) metallomacrocycles [Cp2M(OCH2PPh2)2Ir(cod)]22+ (M = Zr (7),
Ti (8)) and [Cp2Zr(μ-OCH2PPh2)2Rh(nbd)]22+ (9). The crystal structures of the 16-membered
metallomacrocycles 7 and 9 have been determined by X-ray diffraction and show a rhomboidal
arrangement of the metal centers with a conformation that is largely determined on steric
grounds.