Synthesis, molecular structure, solution dynamics, and reactivity of (η-C5H5)2M(μ-PR2) 2Rh(η-indenyl) (M = Zr, Hf; R = Et, Ph)

Article abstract of DOI:10.1021/om00136a002

The metal-containing diphosphines , Cp₂M(PR₂)₂ (Cp = η-C₅H₅; M = Zr, Hf; R = Et, Ph), displace both coordinated ethylenes from (η-C₂H₄)₂Rh(η-indenyl), yielding the early-late heterobimetallic complexes Cp₂M(μ-PR₂)₂Rh(η-indenyl). The molecular structure of Cp₂Zr(μ-PPh₂)₂Rh(η-indenyl) (1c), determined by X-ray diffraction, consists of edge-shared, pseudotetrahedral 16e Zr(IV) and distorted, square-planar Rh(I) centers with a planar ZrP₂Rh bridging unit and a Zr?Rh separation of 3.088 (1) A?. The indenyl ligand exhibits a pronounced slip-fold distortion toward η³-coordination and high barriers (14-15 kcal/mol) to indenyl rotation are observed by ¹H DNMR. Addition of CH₃I to Cp₂M(μ-PEt₂)₂Rh(η-indenyl) affords the cationic d⁰-d⁶ heterobimetallics [Cp₂M(μ-PEt₂)₂Rh (CH₃)(η-indenyl)]I. Red crystals of 1c are monoclinic, P2₁/m (no. 11), with two molecules per unit cell of dimensions a = 9.700 (1) A?, b = 18.855 (3) A?, c = 10.185 (1) A?, and β = 112.95 (1)°. The structure was refined to R = 0.029 and R_w = 0.031 for 2928 observed reflections.