79160-91-1Relevant academic research and scientific papers
Metallocene Derivatives of Early Transition Metals. Part 4. Chemistry of the Complexes and the X-Ray Structures of (M' = C or Si)
Jeffery, John,Lappert, Michael F.,Luong-Thi, N. Tuyet,Webb, Maurice,Atwood, Jerry L.,Hunter, William E.
, p. 1593 - 1605 (2007/10/02)
The metallocene(IV) halogeno-alkyls have been prepared either by interaction of the appropriate Grignard reagent and or from and Mg(CH2SnMe3)X (Cl-X exchange).Metallocene(IV) dialkyls (type (iv) R = CH2SnMe3 = R', M = Ti, Zr, of Hf; type (v) R = CH2SnMe3, R' = CH2SiMe3, M = Ti, Zr, or Hf; type (vi) R = CH2CMe3 = R', M = Ti or Zr; type (vii) R = CH2SnMe3; R' = CH2CMe3, CH2GeMe3, or Me; M = Ti; type (viii) R = CH2SiMe3, R' = CH2GeMe3, M = Ti; type (ix) R = CH(SiMe3)2; R' = Me, Et, Prn, CH2SiMe3, or Ph; M = Zr> have been synthesised by reaction of (a) with 2Mg(CH2SnMe3)X (X = Cl or Br) or (b) with LiR'.Also obtained are and H)2>, the latter from and Li or and successively Lit)3> and Li.The reaction of an equimolar portion of HCl in OEt2 and gives predominantly the products of CH2-SnMe3, rather than Ti-CH2, scission.By contrast, the dialkyls , containing one or two CH2SnMe3 ligands, give largely RH or R'H and ; the relative ability of R as a leaving group decreases in the sequence CH2SnMe3 > CH2CMe3 > CH2SiMe3 >= CH2GeMe3 > CH3, the distinctions being more marked for Ti than Zr of Hf.The dialkyds are generally stable when heated at 80 deg C in PhMe, except for the titanium complexes; (M' = Si or Ge) gives M'Me4 as the sole volatile product, with ti 110 (M' = Si) or 140 min (M' = Sn).Treatment of in C6H6 with CO under ambient conditions affords the appropriate ε2-acyl 2-COR)X> ; the formation of type (xi), rather than the isomer resulting from CO insertion into the less hindered Zr-Me bond, is noteworthy.A single-crystal X-ray diffraction study has been carried out on , with a = 9.142(4), b = 9.142(4). c = 23.326(9) Angstroem, β = 90 deg, and Z = 4.Crystals of (42) are monoclinic, space group P21/n, a = 13.745(6), b = 7.048(3), c = 22.057(9) Angstroem, β = 95.65(4) deg, and Z = 4.For complex (28), 487 reflections have been considered and the data refined to R = 0.029, R' = 0.032; for complex (42), 2688 independent reflections led to R = 0.029, R' = 0.033.The slightly larger steric requirement of the neopentyl ligand compared with -CH2SiMe3 manifests itself in a larger Zr-cyclopentadienyl approach but the Zr-CH2 bond length is indistinguishable, 2.51(2) Angstroem for (28) and 2.52(2) Angstroem for (42).
