Flexible building blocks for transition metal early-late chemistry. Synthesis of heterobimetallic tetranuclear metallomacrocycles

摘要

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 HOCH2PPh 2 with [Cp2ZrMe2], although the reaction with [Cptt 2-ZrMe2] (Cptt = η5-1,3-di-tert-butylcyclopentadienyl) stops at the complex [Cptt 2ZrMe(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-[Pi(οtolyl) 2(Ph2PCH2OH)2] (6), have been prepared by reaction of [M(cod)(NCCH3)2]BF4 and [Pt(οSEt2)(p-tolyl)2]2 with HOCH 2PPh2. 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(OCH 2PPh2)2Ir(cod)]2 2+ (M = Zr (7), Ti (8)) and [Cp2Zr(ο-OCH2PPh2) 2Rh(nbd)]2 2+ (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.