Fulvalene titanium and zirconium complexes: synthesis and NMR study of phosphanido-, alkyl-, and alkynyl-derivatives. X-ray crystal structures of [{ Ti(η5-C5 H 5)(μ-PPh2)}2{μ-(η5-C5H4-η5-C5H4)}] and [{Zr(η5-C5H5)(μ-C=CSiMe3)}2{μ-( η5-C5H4-η5-C5H4)}]

Abstract

Reaction of [{M(1/-C5H 5Xµ-Cl)}z{µ-( 175-C5H 4-175-C5H 4 )}] (M = Ti, 1; Zr, 2) or ({M( 175-C5H 5)Cl 2}z{µ-(175-C5H 4-175-C5H 4)}], (M = Ti, 5; Zr, 6) with one or two equivalents of LiPPh 2 afforded the new phosphanidometal(III) complexes [{M(C5H 5Xµ­ PPh2)h{µ-(175-C5H4- 175-C5H4)}], (M = Ti, 3; Zr, 4). Reaction of 2 with LiO:CSiMe 3 led to the diamagnetic zirconium(III) alkynyl derivative [{Zr(C5H 5Xµ-O:CSiMe 3)}z(µ-175-C5H 4-175-C5H 4 ], 7. Alkylation of 6 with LiCH 2CMe2 Ph gave [{Zr(175- C5H5XCH2CMe2Ph)2}z{µ-( 175-C5H 4-175-C5H 4)}], 8. A detailed NMR study of complexes 3 and 4 allowed the observation of the spectral behaviour of the eight different fulvalene protons through their coupling to the 31P nucleus. The fluxional behaviour of complex 7 was studied by dynamic DNMR, and kinetic parameters for the σ-Π-conversion of the alkynyl ligand were detem1ined. The molecular structures of complexes 3 and 7 were determined by X-ray diffraction methods.