New linear tricobalt complex of Di(2-pyridyl)amide (dpa), [CO3(dpa)4(CH3CN)2][PF6]2

Rodolphe Clérac; F. Albert Cotton; Kim R. Dunbar; Tongbu Lu; Carlos A. Murillo; Xiaoping Wang

doi:10.1021/ic000042o

New linear tricobalt complex of Di(2-pyridyl)amide (dpa), [CO₃(dpa)₄(CH₃CN)₂][PF₆]₂

Rodolphe Clérac, F. Albert Cotton, Kim R. Dunbar, Tongbu Lu, Carlos A. Murillo, Xiaoping Wang

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

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Abstract

Reaction of the linear tricobalt compound Co₃(dpa)₄Cl₂ (1) (dpa = di(2-pyridyl)amide) with silver hexafluoro-phosphate in acetonitrile yields [Co₃(dpa)₄(CH₃CN)₂][PF₆]₂ (2). Two crystalline forms are obtained from the same solution, namely, a monoclinic (P2₁) form 2·CH₃CN·2Et₂O and a triclinic (P1̄) form, 2·3CH₃CN. The tricobalt units in both crystals are essentially symmetrical, though this is not required by crystal symmetry, with Co-Co distances in the range 2.298-2.304 Å. Each of the two terminal Co atoms is coordinated to an acetonitrile molecule with Co-N distances in the range 2.068-2.111 Å at 213 K. The spiral arrangement of ligands gives an overall idealized D₄ point group symmetry for the cation [Co₃(dpa)₄(CH₃CN)2]²⁺. Chiral crystals of both Δ and Λ configurations in the P2₁ form have been isolated. The absolute configurations were determined by X-ray crystallography and their mirror-image circular dichroism spectra measured. The D₄ symmetry of the cation appears to be preserved in solution as judged by the presence of only five proton resonance signals in the ¹H NMR spectrum. Magnetic susceptibility measurements in the solid state indicates that 2 has a doublet ground state and exhibits an increase of the effective moment at high temperature (~160 K) due to a spin crossover process.

Original language	English
Pages (from-to)	3065-3070
Number of pages	6
Journal	Inorganic Chemistry
Volume	39
Issue number	14
DOIs	https://doi.org/10.1021/ic000042o
State	Published - Jul 10 2000
Externally published	Yes

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@article{7271d13698ad4375b33ae3b021f8e6ce,

title = "New linear tricobalt complex of Di(2-pyridyl)amide (dpa), [CO3(dpa)4(CH3CN)2][PF6]2",

abstract = "Reaction of the linear tricobalt compound Co3(dpa)4Cl2 (1) (dpa = di(2-pyridyl)amide) with silver hexafluoro-phosphate in acetonitrile yields [Co3(dpa)4(CH3CN)2][PF6]2 (2). Two crystalline forms are obtained from the same solution, namely, a monoclinic (P21) form 2·CH3CN·2Et2O and a triclinic (P{\=1}) form, 2·3CH3CN. The tricobalt units in both crystals are essentially symmetrical, though this is not required by crystal symmetry, with Co-Co distances in the range 2.298-2.304 {\AA}. Each of the two terminal Co atoms is coordinated to an acetonitrile molecule with Co-N distances in the range 2.068-2.111 {\AA} at 213 K. The spiral arrangement of ligands gives an overall idealized D4 point group symmetry for the cation [Co3(dpa)4(CH3CN)2]2+. Chiral crystals of both Δ and Λ configurations in the P21 form have been isolated. The absolute configurations were determined by X-ray crystallography and their mirror-image circular dichroism spectra measured. The D4 symmetry of the cation appears to be preserved in solution as judged by the presence of only five proton resonance signals in the 1H NMR spectrum. Magnetic susceptibility measurements in the solid state indicates that 2 has a doublet ground state and exhibits an increase of the effective moment at high temperature (~160 K) due to a spin crossover process.",

author = "Rodolphe Cl{\'e}rac and Cotton, {F. Albert} and Dunbar, {Kim R.} and Tongbu Lu and Murillo, {Carlos A.} and Xiaoping Wang",

year = "2000",

month = jul,

day = "10",

doi = "10.1021/ic000042o",

language = "English",

volume = "39",

pages = "3065--3070",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "American Chemical Society",

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T1 - New linear tricobalt complex of Di(2-pyridyl)amide (dpa), [CO3(dpa)4(CH3CN)2][PF6]2

AU - Clérac, Rodolphe

AU - Cotton, F. Albert

AU - Dunbar, Kim R.

AU - Lu, Tongbu

AU - Murillo, Carlos A.

AU - Wang, Xiaoping

PY - 2000/7/10

Y1 - 2000/7/10

N2 - Reaction of the linear tricobalt compound Co3(dpa)4Cl2 (1) (dpa = di(2-pyridyl)amide) with silver hexafluoro-phosphate in acetonitrile yields [Co3(dpa)4(CH3CN)2][PF6]2 (2). Two crystalline forms are obtained from the same solution, namely, a monoclinic (P21) form 2·CH3CN·2Et2O and a triclinic (P1̄) form, 2·3CH3CN. The tricobalt units in both crystals are essentially symmetrical, though this is not required by crystal symmetry, with Co-Co distances in the range 2.298-2.304 Å. Each of the two terminal Co atoms is coordinated to an acetonitrile molecule with Co-N distances in the range 2.068-2.111 Å at 213 K. The spiral arrangement of ligands gives an overall idealized D4 point group symmetry for the cation [Co3(dpa)4(CH3CN)2]2+. Chiral crystals of both Δ and Λ configurations in the P21 form have been isolated. The absolute configurations were determined by X-ray crystallography and their mirror-image circular dichroism spectra measured. The D4 symmetry of the cation appears to be preserved in solution as judged by the presence of only five proton resonance signals in the 1H NMR spectrum. Magnetic susceptibility measurements in the solid state indicates that 2 has a doublet ground state and exhibits an increase of the effective moment at high temperature (~160 K) due to a spin crossover process.

AB - Reaction of the linear tricobalt compound Co3(dpa)4Cl2 (1) (dpa = di(2-pyridyl)amide) with silver hexafluoro-phosphate in acetonitrile yields [Co3(dpa)4(CH3CN)2][PF6]2 (2). Two crystalline forms are obtained from the same solution, namely, a monoclinic (P21) form 2·CH3CN·2Et2O and a triclinic (P1̄) form, 2·3CH3CN. The tricobalt units in both crystals are essentially symmetrical, though this is not required by crystal symmetry, with Co-Co distances in the range 2.298-2.304 Å. Each of the two terminal Co atoms is coordinated to an acetonitrile molecule with Co-N distances in the range 2.068-2.111 Å at 213 K. The spiral arrangement of ligands gives an overall idealized D4 point group symmetry for the cation [Co3(dpa)4(CH3CN)2]2+. Chiral crystals of both Δ and Λ configurations in the P21 form have been isolated. The absolute configurations were determined by X-ray crystallography and their mirror-image circular dichroism spectra measured. The D4 symmetry of the cation appears to be preserved in solution as judged by the presence of only five proton resonance signals in the 1H NMR spectrum. Magnetic susceptibility measurements in the solid state indicates that 2 has a doublet ground state and exhibits an increase of the effective moment at high temperature (~160 K) due to a spin crossover process.

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DO - 10.1021/ic000042o

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JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 14

ER -

New linear tricobalt complex of Di(2-pyridyl)amide (dpa), [CO₃(dpa)₄(CH₃CN)₂][PF₆]₂

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