Cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F): One-electron electrochemical reduction leading to metal-carbon σ-bond cleavage via palladium(i)

Gopa Kar; Steven H. Privér; Lathe A. Jones; Si Xuan Guo; Angel A.J. Torriero; Alan M. Bond; Martin A. Bennett; Suresh K. Bhargava

doi:10.1039/c4dt03268c

Cyclopalladated complexes containing 2-C₆R₄PPh₂ ligands (R = H, F): One-electron electrochemical reduction leading to metal-carbon σ-bond cleavage via palladium(i)

Gopa Kar, Steven H. Privér, Lathe A. Jones, Si Xuan Guo, Angel A.J. Torriero, Alan M. Bond, Martin A. Bennett, Suresh K. Bhargava^*

^*Corresponding author for this work

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

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Abstract

Three new ortho-metallated palladium complexes, [Pd(O,O′-hfacac)(κ²-2-C₆F₄PPh₂)] (11), [Pd₂(O,O′-hfacac)₂(μ-2-C₆F₄PPh₂)₂] (12) and [Pd(O,O′-hfacac)(κC-2-C₆F₄PPh₂)(PPh₃)] (13) (hfacac = hexafluoroacetylacetonate), have been prepared and fully characterised. The electrochemical reductions of complexes 11-13, together with those of other cyclopalladated complexes containing 2-C₆R₄PPh₂ ligands (R = H, F) were studied by cyclic, rotating disk and microelectrode voltammetry. Evidence for the one-electron reduction of [PdI(κ²-2-C₆F₄PPh₂)(PPh₂Fc)] (6) was obtained from coulometric analysis, although the product is unstable and undergoes further chemical processes. Preparative electro-reduction of [Pd₂(μ-Br)₂(κ²-2-C₆F₄PPh₂)₂] (7) in CH₂Cl₂ causes reductive cleavage of its Pd-C σ-bonds and formation of the complex [PdBr₂{PPh₂(2-C₆F₄H)}₂] (14); possible mechanisms are discussed.

Original language	English
Pages (from-to)	3367-3377
Number of pages	11
Journal	Dalton Transactions
Volume	44
Issue number	7
DOIs	https://doi.org/10.1039/c4dt03268c
Publication status	Published - 21 Feb 2015

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@article{c0e2de8f7d5946e2bfab6bcabc0b83a3,

title = "Cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F): One-electron electrochemical reduction leading to metal-carbon σ-bond cleavage via palladium(i)",

abstract = "Three new ortho-metallated palladium complexes, [Pd(O,O′-hfacac)(κ2-2-C6F4PPh2)] (11), [Pd2(O,O′-hfacac)2(μ-2-C6F4PPh2)2] (12) and [Pd(O,O′-hfacac)(κC-2-C6F4PPh2)(PPh3)] (13) (hfacac = hexafluoroacetylacetonate), have been prepared and fully characterised. The electrochemical reductions of complexes 11-13, together with those of other cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F) were studied by cyclic, rotating disk and microelectrode voltammetry. Evidence for the one-electron reduction of [PdI(κ2-2-C6F4PPh2)(PPh2Fc)] (6) was obtained from coulometric analysis, although the product is unstable and undergoes further chemical processes. Preparative electro-reduction of [Pd2(μ-Br)2(κ2-2-C6F4PPh2)2] (7) in CH2Cl2 causes reductive cleavage of its Pd-C σ-bonds and formation of the complex [PdBr2{PPh2(2-C6F4H)}2] (14); possible mechanisms are discussed.",

author = "Gopa Kar and Priv{\'e}r, {Steven H.} and Jones, {Lathe A.} and Guo, {Si Xuan} and Torriero, {Angel A.J.} and Bond, {Alan M.} and Bennett, {Martin A.} and Bhargava, {Suresh K.}",

note = "Publisher Copyright: {\textcopyright} The Royal Society of Chemistry.",

year = "2015",

month = feb,

day = "21",

doi = "10.1039/c4dt03268c",

language = "English",

volume = "44",

pages = "3367--3377",

journal = "Dalton Transactions",

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publisher = "Royal Society of Chemistry",

number = "7",

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TY - JOUR

T1 - Cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F)

T2 - One-electron electrochemical reduction leading to metal-carbon σ-bond cleavage via palladium(i)

AU - Kar, Gopa

AU - Privér, Steven H.

AU - Jones, Lathe A.

AU - Guo, Si Xuan

AU - Torriero, Angel A.J.

AU - Bond, Alan M.

AU - Bennett, Martin A.

AU - Bhargava, Suresh K.

PY - 2015/2/21

Y1 - 2015/2/21

N2 - Three new ortho-metallated palladium complexes, [Pd(O,O′-hfacac)(κ2-2-C6F4PPh2)] (11), [Pd2(O,O′-hfacac)2(μ-2-C6F4PPh2)2] (12) and [Pd(O,O′-hfacac)(κC-2-C6F4PPh2)(PPh3)] (13) (hfacac = hexafluoroacetylacetonate), have been prepared and fully characterised. The electrochemical reductions of complexes 11-13, together with those of other cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F) were studied by cyclic, rotating disk and microelectrode voltammetry. Evidence for the one-electron reduction of [PdI(κ2-2-C6F4PPh2)(PPh2Fc)] (6) was obtained from coulometric analysis, although the product is unstable and undergoes further chemical processes. Preparative electro-reduction of [Pd2(μ-Br)2(κ2-2-C6F4PPh2)2] (7) in CH2Cl2 causes reductive cleavage of its Pd-C σ-bonds and formation of the complex [PdBr2{PPh2(2-C6F4H)}2] (14); possible mechanisms are discussed.

AB - Three new ortho-metallated palladium complexes, [Pd(O,O′-hfacac)(κ2-2-C6F4PPh2)] (11), [Pd2(O,O′-hfacac)2(μ-2-C6F4PPh2)2] (12) and [Pd(O,O′-hfacac)(κC-2-C6F4PPh2)(PPh3)] (13) (hfacac = hexafluoroacetylacetonate), have been prepared and fully characterised. The electrochemical reductions of complexes 11-13, together with those of other cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F) were studied by cyclic, rotating disk and microelectrode voltammetry. Evidence for the one-electron reduction of [PdI(κ2-2-C6F4PPh2)(PPh2Fc)] (6) was obtained from coulometric analysis, although the product is unstable and undergoes further chemical processes. Preparative electro-reduction of [Pd2(μ-Br)2(κ2-2-C6F4PPh2)2] (7) in CH2Cl2 causes reductive cleavage of its Pd-C σ-bonds and formation of the complex [PdBr2{PPh2(2-C6F4H)}2] (14); possible mechanisms are discussed.

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U2 - 10.1039/c4dt03268c

DO - 10.1039/c4dt03268c

M3 - Article

SN - 1477-9226

VL - 44

SP - 3367

EP - 3377

JO - Dalton Transactions

JF - Dalton Transactions

IS - 7

ER -

Cyclopalladated complexes containing 2-C₆R₄PPh₂ ligands (R = H, F): One-electron electrochemical reduction leading to metal-carbon σ-bond cleavage via palladium(i)

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