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Group 4 metallocene complexes with pendant nitrile groups

Publication at Faculty of Science, Central Library of Charles University |
2011

Abstract

The preparation of a new functionalized cyclopentadienyl ligand bearing a nitrile pendant substituent, (C(5)H(4)CMe(2)CH(2)CN)(-) is reported. The corresponding lithium salt of this ligand (1) was prepared by the reaction of in situ lithiated acetonitrile with 6,6-dimethylfulvene.

The ligand was subsequently utilized for the synthesis of group 4 metal complexes [(eta(5)eC(5)H(4)CMe(2)CH(2)CN)(2)MCl(2)] (M = Ti, 2; M = Zr, 3; M - Hf, 4), [(eta(5)eC(5)H(5)) (eta(5)eC(5)H(4)CMe(2)CH(2)CN)MCl(2)] (M - Ti, 7; M Zr, 8), and [(eta(5)-C(5)Me(5)) (eta(5) C(5)H(4)CMe(2)CH(2)CN)(2)ZrCl(2)] (9). Alternative route to 2 comprised the preparation of half-sandwich complex [(h5eC5H4CMe2CH2CN)TiCl(3)] (6).

The prepared compounds were characterized by common spectroscopic methods and the solid state structures of complexes 2, 3, 4, 7, and 9 were determined by the single-crystal X-ray diffraction analysis. In addition, compound 7 was converted to the corresponding dimethyl derivative [(eta(5)eC(5)H(5)) (eta(5)eC(5)H(4)CMe(2)CH(2)CN)TiMe(2)] (10) and also treated with the chloride anion abstractor Li[B(C(6)F(5))(4)] to generate the cationic complex with the coordinated nitrile group, as suggested by the NMR spectroscopy.

A formation of yet another cationic complex was observed upon treating compound 10 with (Ph(3)C)[B(C(6)F(5))(4)].