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Neutral and Cationic [Bis(η 1 ‐amidosilyl)‐η 5 ‐cyclopentadienyl]titanium and ‐zirconium Complexes: Synthesis, X‐ray Molecular Structures and DFT Calculations
Author(s) -
Cano Jesús,
Royo Pascual,
Jacobsen Heiko,
Blacque Olivier,
Berke Heinz,
Herdtweck Eberhardt
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200200698
Subject(s) - chemistry , cyclopentadienyl complex , deprotonation , cationic polymerization , medicinal chemistry , zirconium , metallocene , stereochemistry , toluene , crystallography , inorganic chemistry , catalysis , polymer chemistry , organic chemistry , ion , polymer , polymerization
Treatment of LiNH t Bu with THF solutions of C 5 H 4 (SiMe 2 Cl) 2 gave C 5 H 4 (SiMe 2 NH t Bu) 2 ( 1 ). Deprotonation of 1 with M(NMe 2 ) 4 (M = Ti, Zr) under different conditions provided the monocyclopentadienyl complexes [M{η 5 ‐C 5 H 3 [SiMe 2 (NH t Bu)] 2 }(NMe 2 ) 3 ] [M = Ti ( 2 ), Zr ( 3 )] and the single (η‐amidosilyl)cyclopentadienyl compounds [M{η 5 ‐C 5 H 3 [SiMe 2 (NH t Bu)][SiMe 2 (η 1 ‐N t Bu)]}(NMe 2 ) 2 ] [M = Ti ( 4 ), Zr ( 5 )]. The related dibenzyl compounds [M{η 5 ‐C 5 H 3 [SiMe 2 (NH t Bu)][SiMe 2 (η 1 ‐N t Bu)]}(CH 2 Ph) 2 ] [M = Ti ( 6 ), Zr ( 7 )] resulted from treatment of 1 with M(CH 2 C 6 H 5 ) 4 (M = Ti, Zr). Further deprotonation of the amido complexes 4 and 5 and the benzyl complexes 6 and 7 by heating in toluene solution gave the bis(η‐amidosilyl)cyclopentadienyl complexes [M{η 5 ‐C 5 H 3 [SiMe 2 (η 1 ‐N t Bu)] 2 }(NMe 2 )] [M = Ti ( 8 ), Zr ( 9 )] and [M{η 5 ‐C 5 H 3 [SiMe 2 (η 1 ‐N t Bu)] 2 }(CH 2 Ph)] [M = Ti ( 10 ), Zr ( 11 )], respectively. Treatment of the monobenzyl complexes 10 and 11 with B(C 6 F 5 ) 3 yielded the cationic compounds [M{η 5 ‐C 5 H 3 [SiMe 2 (η 1 ‐N t Bu)] 2 }] + as [(CH 2 Ph)B(C 6 F 5 ) 3 ] − [M = Ti ( 12 ), Zr ( 13 )] salts. All new compounds were characterized by NMR spectroscopy, and the crystal structures of 10 and 13 were studied by diffraction methods. DFT calculations for the neutral and cationic species are described and provide an explanation for the unusual η 1 coordination of a phenyl ring to a group‐4 metal cation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)