Four‐Membered Heterometallacyclic d0 and d1 Complexes of Group 4 Metallocenes with Amidato Ligands |
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Authors: | Dr Martin Haehnel Jacqueline B Priebe Jacky C‐H Yim Dr Anke Spannenberg Prof?Dr Angelika Brückner Prof?Dr Laurel L Schafer Prof?Dr Uwe Rosenthal |
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Institution: | 1. Leibniz‐Institut für Katalyse e.V. an der Universit?t Rostock, Albert‐Einstein‐Strasse 29a, 18059 Rostock (Germany), Fax: (+49)?381‐1281‐51176;2. Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1 (Canada) |
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Abstract: | A study of the coordination chemistry of different amidato ligands (R)N?C(Ph)O] (R=Ph, 2,6‐diisopropylphenyl (Dipp)) at Group 4 metallocenes is presented. The heterometallacyclic complexes Cp2M(Cl){κ2‐N,O‐(R)N?C(Ph)O}] M=Zr, R=Dipp ( 1 a ), Ph ( 1 b ); M=Hf, R=Ph ( 2 )) were synthesized by reaction of Cp2MCl2] with the corresponding deprotonated amides. Complex 1 a was also prepared by direct deprotonation of the amide with Schwartz reagent Cp2Zr(H)Cl]. Salt metathesis reaction of Cp2Zr(H)Cl] with deprotonated amide (Dipp)N?C(Ph)O] gave the zirconocene hydrido complex Cp2M(H){κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 3 ). Reaction of 1 a with Mg did not result in the desired Zr(III) complex but in formation of Mg complex (py)3Mg(Cl) {κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 4 ; py=pyridine). The paramagnetic complexes Cp′2Ti{κ2‐N,O‐(R)N?C(Ph)O}] (Cp′=Cp, R=Ph ( 7 a ); Cp′=Cp, R=Dipp ( 7 b ); Cp′=Cp*, R=Ph ( 8 )) were prepared by the reaction of the known titanocene alkyne complexes Cp2′Ti(η2‐Me3SiC2SiMe3)] (Cp′=Cp ( 5 ), Cp′=Cp* ( 6 )) with the corresponding amides. Complexes 1 a , 2 , 3 , 4 , 7 a , 7 b , and 8 were characterized by X‐ray crystallography. The structure and bonding of complexes 7 a and 8 were also characterized by EPR spectroscopy. |
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Keywords: | amidates EPR spectroscopy hafnium metallacycles titanium zirconium |
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