Isolable Zirconium(IV) Carbonyl Complexes. Synthesis and Characterization of (C5R5)2Zr(.eta.2-COCH3)(CO)+ Species (R = Me, H)

Zhaoyu Guo; Dale C Swenson; Anil S Guram; Richard F Jordan

doi:10.1021/om00015a009

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Isolable Zirconium(IV) Carbonyl Complexes. Synthesis and Characterization of (C5R5)2Zr(.eta.2-COCH3)(CO)+ Species (R = Me, H)

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Isolable Zirconium(IV) Carbonyl Complexes. Synthesis and Characterization of (C5R5)2Zr(.eta.2-COCH3)(CO)+ Species (R = Me, H)

Zhaoyu Guo, Dale C Swenson, Anil S Guram and Richard F Jordan

Organometallics, Vol.13(3), pp.766-773

03/01/1994

DOI: 10.1021/om00015a009

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Abstract

The synthesis and characterization of the first isolable terminal carbonyl complex of Zr(IV) is described. The reaction of (C5R5)2Zr(CH3) (μ-CH3)B(C6F6)3 with CO yields the η2-acyl carbonyl complexes [(C5R5)2Zr(η2-COCH3)(CO)] [CH3B(C6F5)3] (2, R = Me; 3, R = H). Complex 2 exists as a 9/1 mixture of “O-outside” (2a) and “O-inside” (2b) isomers which differ in the orientation of the η2-acyl ligand. Analogous O-outside (3a) and O-inside (3b) isomers are observed for 3, but the isomer preference is reversed (3a/3b = 1/5). The νCO values for the O-inside isomers 2b (2152 cm-1) and 3b (2176 cm-1) are higher than the free CO value, indicating that the Zr-CO bond is primarily σ-donor in character. The νCO values for the O-outside isomers 2a (2105 cm-1) and 3a (2123 cm-1) are slightly lower than the free CO value, as a result of overlap of a filled Zr-acyl bonding orbital and a CO π* orbital (i.e. σ→π* back-bonding). 2a can be isolated as a thermally stable solid; however, in CH2Cl2 solution both 2 and 3 lose CO under vacuum. 2a has been characterized by single crystal X-ray diffraction: a = 16.951(5) Å, b = 10.642(4) Å, c = 22.217(6) Å, V = 4008(4) Å3, Z = 4 in space group, Pca21. Consistent with the νCO values, the C-O distance (1.13(1) Å) in the nearly linear carbonyl ligand (Zr-C-O angle 175.1(7)°) is not significantly perturbed from that in free CO. The Zr-CCO distance (2.25(1) Å) is consistent with the absence of significant Zr-C π-bonding.

Details

Title: Subtitle: Isolable Zirconium(IV) Carbonyl Complexes. Synthesis and Characterization of (C5R5)2Zr(.eta.2-COCH3)(CO)+ Species (R = Me, H)
Creators: Zhaoyu Guo
Dale C Swenson
Anil S Guram
Richard F Jordan
Resource Type: Journal article
Publication Details: Organometallics, Vol.13(3), pp.766-773
Publisher: American Chemical Society
DOI: 10.1021/om00015a009
ISSN: 0276-7333
eISSN: 1520-6041
Language: English
Date published: 03/01/1994
Academic Unit: Chemistry
Record Identifier: 9984622749902771

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