Synthesis and characterization of Cp2Zr(CH{Me}{6-ethylpyrid-2-yl})(CO)+, a d° metal alkyl carbonyl complex. Coordination chemistry of the four-membered azazirconacycle Cp2Zr(η2-C,N-CH{Me}{6-ethylpyrid-2-yl})

Anil S Guram; Dale C Swenson; Richard F Jordan

doi:10.1021/ja00049a033

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Synthesis and characterization of Cp2Zr(CH{Me}{6-ethylpyrid-2-yl})(CO)+, a d° metal alkyl carbonyl complex. Coordination chemistry of the four-membered azazirconacycle Cp2Zr(η2-C,N-CH{Me}{6-ethylpyrid-2-yl})

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Synthesis and characterization of Cp2Zr(CH{Me}{6-ethylpyrid-2-yl})(CO)+, a d° metal alkyl carbonyl complex. Coordination chemistry of the four-membered azazirconacycle Cp2Zr(η2-C,N-CH{Me}{6-ethylpyrid-2-yl})

Anil S Guram, Dale C Swenson and Richard F Jordan

Journal of the American Chemical Society, Vol.114(23), pp.8991-8996

11/01/1992

DOI: 10.1021/ja00049a033

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Abstract

The cationic complex Cp2Zr(CH3)(THF)+ (1, as the BPh4- salt) reacts with 2,6-diethylpyridine to afford the chelated secondary zirconocene-alkyl complex Cp2Zr(η2-C,N-CH{Me}{6-ethylpyrid-2-yl})+ (2). Treatment of complex 2 with CO, CH3CN, tBuCN, and (PhCH2)(Et)3N+Cr affords Cp2Zr(CH{Me}}6-ethylpyrid-2-yl})(CO)+ (3), Cp2Zr(CH{Me}{6-ethylpyrid-2- yl})(CH3CN)+ (4), Cp2Zr(CH{Me}6-ethylpyrid-2-yl})(tBuCN)+ (5), and Cp2Zr(CH{Me}{6-ethylpyrid-2-yl})(Cl) (6), respectively. The thermally sensitive d0 carbonyl complex 3 is a rare example of a d0 M(alkyl)-CO adduct and is unambiguously characterized in solution by low-temperature NMR and IR spectroscopy, 13C-labeling and hydrolysis experiments, and decomposition studies. IR and NMR data establish that 3 contains a terminal CO ligand. An X-ray structure analysis of 6 establishes that the CH(Me)(6-ethylpyrid-2-yl) ligand adopts a chelated structure; the similarity of the spectroscopic data for 3-6 implies that 3-5 have similar chelated structures. At room temperature, 3 in CD2Cl2 rapidly decomposes to afford a complex mixture of products. 1H NMR monitoring of the decomposition of 3 reveals formation of a transient cationic zirconocene-acyl intermediate 9, which undergoes 1,2-H shift to afford a mixture of isomeric/oligomeric zirconocene-enolates. Treatment of this mixture with (PhCH2)(Et)3N+CT affords Cp2Zr(OCH=C{Me}{6-ethylpyrid-2-yl})Cl (10) as a mixture of E/Z isomers, establishing the presence of zirconocene-enolate species. Hydrolysis of the decomposition products of 3 affords a mixture of thermally sensitive tautomers, enol 11/aldehyde 11′, which are characterized by NMR, FTIR, and mass spectroscopy.

Organic Chemistry

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Condensed matter: structure, mechanical and thermal properties

Exact sciences and technology

Organic compounds

Organometalloidal and organometallic compounds

Preparations and properties

Structure of solids and liquids; crystallography

Structure of specific crystalline solids

Transition metals derivatives

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Title: Subtitle: Synthesis and characterization of Cp2Zr(CH{Me}{6-ethylpyrid-2-yl})(CO)+, a d° metal alkyl carbonyl complex. Coordination chemistry of the four-membered azazirconacycle Cp2Zr(η2-C,N-CH{Me}{6-ethylpyrid-2-yl})
Creators: Anil S Guram - Univ. Iowa, dep. chemistry, Iowa City IA 52242, United States
Dale C Swenson - University of Iowa
Richard F Jordan - Univ. Iowa, dep. chemistry, Iowa City IA 52242, United States
Resource Type: Journal article
Publication Details: Journal of the American Chemical Society, Vol.114(23), pp.8991-8996
Publisher: American Chemical Society
DOI: 10.1021/ja00049a033
ISSN: 0002-7863
eISSN: 1520-5126
Language: English
Date published: 11/01/1992
Academic Unit: Chemistry
Record Identifier: 9984622047802771

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