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Group 4 diene complexes stabilized by phosphine donors Haddad, Timothy S.
Abstract
The synthesis of eight fluxional, diamagnetic group 4 complexes MR'(C₄H₆)[N(SiMe₂CH₂PR₂)₂] (M = Hf, Zr; R' = Ph, CH₂CMe₃; R = Me) and (M = Hf, Zr, R' = Cl; R = Me, CHMe₂ has been achieved. The X-ray crystallographic results of two of these complexes (M = Hf, Zr; R' = Ph; R = Me) indicate that the bonding of the diene unit has a significantly higher degree of ƞ⁴-π character than is present in Cp₂M(diene) (M = Hf, Zr) complexes, and therefore the M(II) resonance structure has more contribution to the overall bonding scheme. Consistent with all the NMR data available is that these complexes maintain a meridional coordination of the tridentate amide-phosphine ligand both in solution and in the solid state. The observed fluxional process is best described as diene rotation. Two of the diene complexes (M = Hf; R' = Cl; R = Me, CHMe₂ were found to react with allylmagnesium chloride and subsequently undergo a unique C-C bond forming reaction and rearrangement to generate two new non-fluxional diene complexes Hf [(ƞ⁴-CH₂CHCHCH)CH₂CH₂CH₂][N(SiMe₂CH₂PR₂)₂] (R = Me or CHMe₂). The latter of these two complexes has been crystallographically characterized.
Item Metadata
Title |
Group 4 diene complexes stabilized by phosphine donors
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1987
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Description |
The synthesis of eight fluxional, diamagnetic group 4 complexes MR'(C₄H₆)[N(SiMe₂CH₂PR₂)₂] (M = Hf, Zr; R' = Ph, CH₂CMe₃; R = Me) and (M = Hf, Zr, R' = Cl; R = Me, CHMe₂ has been achieved. The X-ray crystallographic results of two of these complexes (M = Hf, Zr; R' = Ph; R = Me) indicate that the bonding of the diene unit has a significantly higher degree of ƞ⁴-π character than is present in Cp₂M(diene) (M = Hf, Zr) complexes, and therefore the M(II) resonance structure has more contribution to the overall bonding scheme.
Consistent with all the NMR data available is that these complexes maintain a meridional coordination of the tridentate amide-phosphine ligand both in solution and in the solid state. The observed fluxional process is best described as diene rotation. Two of the diene complexes (M = Hf; R' = Cl; R = Me, CHMe₂ were found to react with allylmagnesium chloride and subsequently undergo a unique C-C bond forming reaction and rearrangement to generate two new non-fluxional diene complexes Hf [(ƞ⁴-CH₂CHCHCH)CH₂CH₂CH₂][N(SiMe₂CH₂PR₂)₂] (R = Me or CHMe₂). The latter of these two complexes has been crystallographically characterized.
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Type | |
Language |
eng
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Date Available |
2010-07-14
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0059714
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Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.