Reactions of (η5-C5H5)(η5-C5Me5)ZrX (X = Cl, Me) complexes with carbon monoxide and the isocyanide 2,6-Me2C6H3NC. Crystal structure of (η5-C5H5)(η5C5Me5)Zr2-C(N-2,6-Me2C6H3)Si(SiMe3)3>Cl

Article abstract of DOI:10.1016/0022-328X(88)87078-5

The new tris(trimethylsilyl)silylzirconium derivative (η⁵-C5H5)(η⁵-C5Me5)ZrCl (1) is prepared by reaction of (Η⁵-C5H5)(η⁵-C5Me5)ZrCl2 with (THF)3LiSi(SiMe3)3.Mixed alkyl/silyl complex (η⁵-C5H5)(η⁵-C5Me5)ZrMe (2) is obtained after treatment of 1 with MeMgBr.Reactions of compounds 1 and 2 with carbon monoxide and 2,6-Me2C6H3NC are described.Carbon monoxide inserts cleanly into the Zr-Si bond of 1, giving the η²-silaacyl (η⁵-C5H5)(η⁵-C5Me5)Zr<η²-COSi(SiMe3)3>Cl (3).The reaction of 2 with CO proceeds via the intermediate (η⁵-C5H5)(η⁵-C5Me5)Zr<η²-COSi(SiMe3)3>Me (4) to the enolate hydride (η⁵-C5H5)(η⁵-C5Me5)ZrH (5).A mechanism for this rearrangement is proposed.This chemistry contrasts with that previously observed for (η⁵-C5H5)2ZrMe, which reacts with CO to cleanly give the stable acyl (η⁵-C5H5)2Zr(η²-COMe).Methyl iodide and compound 5 react to give the iodide (η⁵-C5H5)(η⁵-C5Me5)ZrI (6) and methane.The reaction of 5 with 2 equivalents of HCl provides a new synthetic route to an acysilane MeCOSi(SiMe3)3.Reactions of 1 and 2 with the isocyanide 2,6-Me2C6H3NC give the insertion products (η⁵-C5H5)(η⁵-C5Me5)Zr<η²-C(N-2,6-Me2C6H3)Si(SiMe3)3>Cl (7) and (η⁵-C5H5)(η⁵-C5Me5)Zr<η²-C(N-2,6-Me2C6H3)-Me>Si(SiMe3)3 (8), respectively.Steric crowding in these compounds is evidenced by restricted rotation about the N-C(xylyl) bonds.An X-ray crystal structure of 7 has been determined.Crystals of 7 are monoclinic, P2₁/c, with a 18.276(6) Angstroem, b 9.993(3) Angstroem, c 21.550(5) Angstroem, β 106.25(3) deg; V 3779(2) Angstroem³, Z = 4, R_F 6.63percent R_wF 6.48percent.