Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene

Jonathan J. Loughrey, Nathan J. Patmore, Amgalanbaatar Baldansuren, Alistair J. Fielding, Eric J L McInnes, Michaele J. Hardie, Stephen Sproules, Malcolm A. Halcrow

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Abstract

Three complexes of cyclotricatechylene (H6ctc), [{PtL}33-ctc)], have been synthesised: (L = 1,2-bis(diphenylphosphino)benzene {dppb}, 1; L = 1,2-bis(diphenylphosphino)ethane {dppe}, 2; L = 4,4′-bis(tert-butyl)-2,2′-bipyridyl {tBu2bipy}, 3). The complexes show three low-potential, chemically reversible voltammetric oxidations separated by ca. 180 mV, corresponding to stepwise oxidation of the [ctc]6- catecholato rings to the semiquinonate level. The redox series [1]0/1+/2+/3+ and [3]0/1+/2+/3+ have been characterised by UV/vis/NIR spectroelectrochemistry. The mono- and di-cations have class II mixed valent character, with reduced radical delocalisation compared to an analogous bis-dioxolene system. The SOMO composition of [1]+ and [3]+ has been delineated by cw EPR, ENDOR and HYSCORE spectroscopies, with the aid of two monometallic model compounds [PtL(DBsq)]+ (DBsqH = 3,5-bis(tert-butyl)-1,2-benzosemiquinone; L = dppe or tBu2bipy). DF and time-dependent DF calculations confirm these interpretations, and demonstrate changes to spin-delocalisation in the ctc macrocycle as it is sequentially oxidised.

LanguageEnglish
Pages6935-6948
Number of pages14
JournalChemical Science
Volume6
Issue number12
DOIs
Publication statusPublished - 2015

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2,2'-Dipyridyl
Platinum
Cations
Spectroelectrochemistry
Oxidation
Ethane
Paramagnetic resonance
Spectroscopy
Chemical analysis
Oxidation-Reduction
1,2-bis(diphenylphosphino)benzene
bis(diphenylphosphine)ethane

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Loughrey, J. J., Patmore, N. J., Baldansuren, A., Fielding, A. J., McInnes, E. J. L., Hardie, M. J., ... Halcrow, M. A. (2015). Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene. Chemical Science, 6(12), 6935-6948. https://doi.org/10.1039/c5sc02776d
Loughrey, Jonathan J. ; Patmore, Nathan J. ; Baldansuren, Amgalanbaatar ; Fielding, Alistair J. ; McInnes, Eric J L ; Hardie, Michaele J. ; Sproules, Stephen ; Halcrow, Malcolm A. / Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene. In: Chemical Science. 2015 ; Vol. 6, No. 12. pp. 6935-6948.
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title = "Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene",
abstract = "Three complexes of cyclotricatechylene (H6ctc), [{PtL}3(μ3-ctc)], have been synthesised: (L = 1,2-bis(diphenylphosphino)benzene {dppb}, 1; L = 1,2-bis(diphenylphosphino)ethane {dppe}, 2; L = 4,4′-bis(tert-butyl)-2,2′-bipyridyl {tBu2bipy}, 3). The complexes show three low-potential, chemically reversible voltammetric oxidations separated by ca. 180 mV, corresponding to stepwise oxidation of the [ctc]6- catecholato rings to the semiquinonate level. The redox series [1]0/1+/2+/3+ and [3]0/1+/2+/3+ have been characterised by UV/vis/NIR spectroelectrochemistry. The mono- and di-cations have class II mixed valent character, with reduced radical delocalisation compared to an analogous bis-dioxolene system. The SOMO composition of [1]+ and [3]+ has been delineated by cw EPR, ENDOR and HYSCORE spectroscopies, with the aid of two monometallic model compounds [PtL(DBsq)]+ (DBsqH = 3,5-bis(tert-butyl)-1,2-benzosemiquinone; L = dppe or tBu2bipy). DF and time-dependent DF calculations confirm these interpretations, and demonstrate changes to spin-delocalisation in the ctc macrocycle as it is sequentially oxidised.",
author = "Loughrey, {Jonathan J.} and Patmore, {Nathan J.} and Amgalanbaatar Baldansuren and Fielding, {Alistair J.} and McInnes, {Eric J L} and Hardie, {Michaele J.} and Stephen Sproules and Halcrow, {Malcolm A.}",
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Loughrey, JJ, Patmore, NJ, Baldansuren, A, Fielding, AJ, McInnes, EJL, Hardie, MJ, Sproules, S & Halcrow, MA 2015, 'Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene', Chemical Science, vol. 6, no. 12, pp. 6935-6948. https://doi.org/10.1039/c5sc02776d

Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene. / Loughrey, Jonathan J.; Patmore, Nathan J.; Baldansuren, Amgalanbaatar; Fielding, Alistair J.; McInnes, Eric J L; Hardie, Michaele J.; Sproules, Stephen; Halcrow, Malcolm A.

In: Chemical Science, Vol. 6, No. 12, 2015, p. 6935-6948.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Platinum(II) complexes of mixed-valent radicals derived from cyclotricatechylene, a macrocyclic tris-dioxolene

AU - Loughrey, Jonathan J.

AU - Patmore, Nathan J.

AU - Baldansuren, Amgalanbaatar

AU - Fielding, Alistair J.

AU - McInnes, Eric J L

AU - Hardie, Michaele J.

AU - Sproules, Stephen

AU - Halcrow, Malcolm A.

PY - 2015

Y1 - 2015

N2 - Three complexes of cyclotricatechylene (H6ctc), [{PtL}3(μ3-ctc)], have been synthesised: (L = 1,2-bis(diphenylphosphino)benzene {dppb}, 1; L = 1,2-bis(diphenylphosphino)ethane {dppe}, 2; L = 4,4′-bis(tert-butyl)-2,2′-bipyridyl {tBu2bipy}, 3). The complexes show three low-potential, chemically reversible voltammetric oxidations separated by ca. 180 mV, corresponding to stepwise oxidation of the [ctc]6- catecholato rings to the semiquinonate level. The redox series [1]0/1+/2+/3+ and [3]0/1+/2+/3+ have been characterised by UV/vis/NIR spectroelectrochemistry. The mono- and di-cations have class II mixed valent character, with reduced radical delocalisation compared to an analogous bis-dioxolene system. The SOMO composition of [1]+ and [3]+ has been delineated by cw EPR, ENDOR and HYSCORE spectroscopies, with the aid of two monometallic model compounds [PtL(DBsq)]+ (DBsqH = 3,5-bis(tert-butyl)-1,2-benzosemiquinone; L = dppe or tBu2bipy). DF and time-dependent DF calculations confirm these interpretations, and demonstrate changes to spin-delocalisation in the ctc macrocycle as it is sequentially oxidised.

AB - Three complexes of cyclotricatechylene (H6ctc), [{PtL}3(μ3-ctc)], have been synthesised: (L = 1,2-bis(diphenylphosphino)benzene {dppb}, 1; L = 1,2-bis(diphenylphosphino)ethane {dppe}, 2; L = 4,4′-bis(tert-butyl)-2,2′-bipyridyl {tBu2bipy}, 3). The complexes show three low-potential, chemically reversible voltammetric oxidations separated by ca. 180 mV, corresponding to stepwise oxidation of the [ctc]6- catecholato rings to the semiquinonate level. The redox series [1]0/1+/2+/3+ and [3]0/1+/2+/3+ have been characterised by UV/vis/NIR spectroelectrochemistry. The mono- and di-cations have class II mixed valent character, with reduced radical delocalisation compared to an analogous bis-dioxolene system. The SOMO composition of [1]+ and [3]+ has been delineated by cw EPR, ENDOR and HYSCORE spectroscopies, with the aid of two monometallic model compounds [PtL(DBsq)]+ (DBsqH = 3,5-bis(tert-butyl)-1,2-benzosemiquinone; L = dppe or tBu2bipy). DF and time-dependent DF calculations confirm these interpretations, and demonstrate changes to spin-delocalisation in the ctc macrocycle as it is sequentially oxidised.

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U2 - 10.1039/c5sc02776d

DO - 10.1039/c5sc02776d

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EP - 6948

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T2 - Chemical Science

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SN - 2041-6520

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