Bis(acetylacetonate) tungsten(IV) complexes containing a π-basic diazoalkane or oxo ligand

Chetna Khosla; Andrew B. Jackson; Peter S. White; Joseph L. Templeton

doi:10.1021/om201050j

Bis(acetylacetonate) tungsten(IV) complexes containing a π-basic diazoalkane or oxo ligand

Chetna Khosla, Andrew B. Jackson, Peter S. White, Joseph L. Templeton

Research output: Contribution to journal › Article › peer-review

25 Scopus citations

Abstract

Tungsten(IV) bis(acetylacetonate) (acetylacetonate = acac) complexes were synthesized by incorporating either a diazoalkane or an oxo ligand into the coordination sphere of a tungsten(II) reagent. The reaction of free diazoalkane (N ₂CRR′) with W(CO) ₃(acac) ₂ leads to loss of two carbon monoxide ligands and coordination of the diazoalkane reagent through the terminal nitrogen to produce W(CO)(acac) ₂(N ₂CRR′). This monomer is best formulated as a tungsten(IV) complex. A second example of converting a d ⁴ tungsten carbonyl complex to a d ² product involves oxidation of W(CO)(acac) ₂(PhC≡N) with m-chloroperoxybenzoic acid (MCPBA) to replace the CO ligand with an oxygen atom. This increase in metal oxidation state causes rotation of the nitrile ligand by 90° relative to the two bidentate acac ligands. Electrophilic addition at the nitrogen of the π-bound nitrile ligand using methyl triflate (MeOTf) and subsequent nucleophilic addition at carbon with sodium trimethoxyborohydride, Na[HB(OMe) ₃], reduces the C≡N bond stereoselectively and produces the neutral imine complex W(O)(acac) ₂(PhHC=NMe) with a diastereomeric ratio of 11:1.

Original language	English (US)
Pages (from-to)	987-994
Number of pages	8
Journal	Organometallics
Volume	31
Issue number	3
DOIs	https://doi.org/10.1021/om201050j
State	Published - Feb 13 2012
Externally published	Yes

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Organic Chemistry
Inorganic Chemistry

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title = "Bis(acetylacetonate) tungsten(IV) complexes containing a π-basic diazoalkane or oxo ligand",

abstract = "Tungsten(IV) bis(acetylacetonate) (acetylacetonate = acac) complexes were synthesized by incorporating either a diazoalkane or an oxo ligand into the coordination sphere of a tungsten(II) reagent. The reaction of free diazoalkane (N 2CRR′) with W(CO) 3(acac) 2 leads to loss of two carbon monoxide ligands and coordination of the diazoalkane reagent through the terminal nitrogen to produce W(CO)(acac) 2(N 2CRR′). This monomer is best formulated as a tungsten(IV) complex. A second example of converting a d 4 tungsten carbonyl complex to a d 2 product involves oxidation of W(CO)(acac) 2(PhC≡N) with m-chloroperoxybenzoic acid (MCPBA) to replace the CO ligand with an oxygen atom. This increase in metal oxidation state causes rotation of the nitrile ligand by 90° relative to the two bidentate acac ligands. Electrophilic addition at the nitrogen of the π-bound nitrile ligand using methyl triflate (MeOTf) and subsequent nucleophilic addition at carbon with sodium trimethoxyborohydride, Na[HB(OMe) 3], reduces the C≡N bond stereoselectively and produces the neutral imine complex W(O)(acac) 2(PhHC=NMe) with a diastereomeric ratio of 11:1.",

author = "Chetna Khosla and Jackson, {Andrew B.} and White, {Peter S.} and Templeton, {Joseph L.}",

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AU - Khosla, Chetna

AU - Jackson, Andrew B.

AU - White, Peter S.

AU - Templeton, Joseph L.

PY - 2012/2/13

Y1 - 2012/2/13

N2 - Tungsten(IV) bis(acetylacetonate) (acetylacetonate = acac) complexes were synthesized by incorporating either a diazoalkane or an oxo ligand into the coordination sphere of a tungsten(II) reagent. The reaction of free diazoalkane (N 2CRR′) with W(CO) 3(acac) 2 leads to loss of two carbon monoxide ligands and coordination of the diazoalkane reagent through the terminal nitrogen to produce W(CO)(acac) 2(N 2CRR′). This monomer is best formulated as a tungsten(IV) complex. A second example of converting a d 4 tungsten carbonyl complex to a d 2 product involves oxidation of W(CO)(acac) 2(PhC≡N) with m-chloroperoxybenzoic acid (MCPBA) to replace the CO ligand with an oxygen atom. This increase in metal oxidation state causes rotation of the nitrile ligand by 90° relative to the two bidentate acac ligands. Electrophilic addition at the nitrogen of the π-bound nitrile ligand using methyl triflate (MeOTf) and subsequent nucleophilic addition at carbon with sodium trimethoxyborohydride, Na[HB(OMe) 3], reduces the C≡N bond stereoselectively and produces the neutral imine complex W(O)(acac) 2(PhHC=NMe) with a diastereomeric ratio of 11:1.

AB - Tungsten(IV) bis(acetylacetonate) (acetylacetonate = acac) complexes were synthesized by incorporating either a diazoalkane or an oxo ligand into the coordination sphere of a tungsten(II) reagent. The reaction of free diazoalkane (N 2CRR′) with W(CO) 3(acac) 2 leads to loss of two carbon monoxide ligands and coordination of the diazoalkane reagent through the terminal nitrogen to produce W(CO)(acac) 2(N 2CRR′). This monomer is best formulated as a tungsten(IV) complex. A second example of converting a d 4 tungsten carbonyl complex to a d 2 product involves oxidation of W(CO)(acac) 2(PhC≡N) with m-chloroperoxybenzoic acid (MCPBA) to replace the CO ligand with an oxygen atom. This increase in metal oxidation state causes rotation of the nitrile ligand by 90° relative to the two bidentate acac ligands. Electrophilic addition at the nitrogen of the π-bound nitrile ligand using methyl triflate (MeOTf) and subsequent nucleophilic addition at carbon with sodium trimethoxyborohydride, Na[HB(OMe) 3], reduces the C≡N bond stereoselectively and produces the neutral imine complex W(O)(acac) 2(PhHC=NMe) with a diastereomeric ratio of 11:1.

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Bis(acetylacetonate) tungsten(IV) complexes containing a π-basic diazoalkane or oxo ligand

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