Molecular and Electronic Structures of Bis(pyridine-2,6-diimine)metal Complexes [ML2](PF6)n (n = 0, 1, 2, 3; M = Mn, Fe, Co, Ni, Cu, Zn)

Bruin, Bas de; Bill, Eckhard; Bothe, Eberhard; Weyhermüller, Thomas; Wieghardt, Karl

doi:10.1021/ic000113j

Cited by 326 publications

(288 citation statements)

References 46 publications

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“…In addition to the bands due to the presence of L2, the infrared spectra of the non-chloride complexes also contain bands associated with the various anions present. at about 840 and 557 cm À1 , [20] are present in the infrared spectrum of complex 2, although the first of these, centred at 835 cm…”

Section: Resultsmentioning

confidence: 98%

Coordination Algorithms Control Molecular Architecture: [Cu^I₄(L2)₄]⁴⁺ Grid Complex Versus [M^II₂(L2)₂X₄]^y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [Fe^II(L2)₃][Cl₃Fe^IIIOFe^IIICl₃]

Lan

Kennepohl

Moubaraki

et al. 2003

Chemistry A European J

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The synthesis and characterisation of a pyridazine-containing two-armed grid ligand L2 (prepared from one equivalent of 3,6-diformylpyridazine and two equivalents of p-anisidine) and the resulting transition metal (Zn, Cu, Ni, Co, Fe, Mn) complexes (1-9) are reported. Single-crystal X-ray structure determinations revealed that the copper(I) complex had self-assembled as a [2 x 2] grid, [Cu(I) (4)(L2)(4)][PF(6)](4).(CH(3)CN)(H(2)O)(CH(3)CH(2)OCH(2)CH(3))(0.25) (2.(CH(3)CN)(H(2)O)(CH(3)CH(2)OCH(2)CH(3))(0.25)), whereas the [Zn(2)(L2)(2)(CH(3)CN)(2)(H(2)O)(2)][ClO(4)](4).CH(3)CN (1.CH(3)CN), [Ni(II) (2)(L2)(2)(CH(3)CN)(4)][BF(4)](4).(CH(3)CH(2)OCH(2)CH(3))(0.25) (5 a.(CH(3)CH(2)OCH(2)CH(3))(0.25)) and [Co(II) (2)(L2)(2)(H(2)O)(2)(CH(3)CN)(2)][ClO(4)](4).(H(2)O)(CH(3)CN)(0.5) (6 a.(H(2)O)(CH(3)CN)(0.5)) complexes adopt a side-by-side architecture; iron(II) forms a monometallic cation binding three L2 ligands, [Fe(II)(L2)(3)][Fe(III)Cl(3)OCl(3)Fe(III)].CH(3)CN (7.CH(3)CN). A more soluble salt of the cation of 7, the diamagnetic complex [Fe(II)(L2)(3)][BF(4)](2).2 H(2)O (8), was prepared, as well as two derivatives of 2, [Cu(I) (2)(L2)(2)(NCS)(2)].H(2)O (3) and [Cu(I) (2)(L2)(NCS)(2)] (4). The manganese complex, [Mn(II) (2)(L2)(2)Cl(4)].3 H(2)O (9), was not structurally characterised, but is proposed to adopt a side-by-side architecture. Variable temperature magnetic susceptibility studies yielded small negative J values for the side-by-side complexes: J=-21.6 cm(-1) and g=2.17 for S=1 dinickel(II) complex [Ni(II) (2)(L2)(2)(H(2)O)(4)][BF(4)](4) (5 b) (fraction monomer 0.02); J=-7.6 cm(-1) and g=2.44 for S= 3/2 dicobalt(II) complex [Co(II) (2)(L2)(2)(H(2)O)(4)][ClO(4)](4) (6 b) (fraction monomer 0.02); J=-3.2 cm(-1) and g=1.95 for S= 5/2 dimanganese(II) complex 9 (fraction monomer 0.02). The double salt, mixed valent iron complex 7.H(2)O gave J=-75 cm(-1) and g=1.81 for the S= 5/2 diiron(III) anion (fraction monomer=0.025). These parameters are lower than normal for Fe(III)OFe(III) species because of fitting of superimposed monomer and dimer susceptibilities arising from trace impurities. The iron(II) centre in 7.H(2)O is low spin and hence diamagnetic, a fact confirmed by the preparation and characterisation of the simple diamagnetic iron(II) complex 8. Mössbauer measurements at 77 K confirmed that there are two iron sites in 7.H(2)O, a low-spin iron(II) site and a high-spin diiron(III) site. A full electrochemical investigation was undertaken for complexes 1, 2, 5 b, 6 b and 8 and this showed that multiple redox processes are a feature of all of them.

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Section: Resultsmentioning

confidence: 98%

Coordination Algorithms Control Molecular Architecture: [Cu^I₄(L2)₄]⁴⁺ Grid Complex Versus [M^II₂(L2)₂X₄]^y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [Fe^II(L2)₃][Cl₃Fe^IIIOFe^IIICl₃]

Lan

Kennepohl

Moubaraki

et al. 2003

Chemistry A European J

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“…The EPR parameters for Cu(II) complexes are determined by the chemical composition and the geometry of the atoms nearest to the metal ion. The significant increase in the axial ligand field in this complex is most probably reflected in the measured values of the hyperfine coupling constants, which are much smaller than the values of A found for six-coordinate complexes of distorted octahedral geometry, such as the bis(pyridine-2,6-diimine) Cu(II) complex (A =145 × 10 − 4 cm − 1 ), with six nitrogen atoms in the coordination sphere [11], or the [Cu(NOTA)] − complex (NOTA =1,4,7-triazacyclononane-1,4,7-triacetate) (A =149.5 × 10 − 4 cm − 1 ), with three nitrogen and tree oxygen atoms in the coordination sphere [12].…”

Section: Epr Spectroscopymentioning

confidence: 59%

Copper complexes with bibracchial lariat ethers: from mono- to binuclear structures

Rodrı́guez-Infante

Esteban‐Gómez

Avecilla

et al. 2001

Inorganica Chimica Acta

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Copper(II) complexes with a series of bibracchial lariat ethers are described. Independently of the nature of the counterion present (nitrate or perchlorate), the lariat ether N, N%-bis(2-aminobenzyl)-1,10-diaza-15-crown-5 (L 1 ) always forms mononuclear complexes, whereas the lariat ethers N, N%-bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L 2 ) and N,N%-bis(2-salicylaldiminobenzyl)-4,13-diaza-18-crown-6 (L 3 ) only give binuclear compounds. The X-ray crystal structure of [CuL 1 ](ClO 4 ) 2 shows a seven-coordinated copper(II) ion in a distorted (axially compressed) pentagonal-bipyramidal geometry. The X-ray crystal structure of [Cu 2 (L 3 -2H)](ClO 4 ) 2 confirms the binuclear nature of the compound with both metal ions having identical coordination environments and each one placed out of the crown hole but efficiently encapsulated by the corresponding pendant arm; each copper(II) ion is five-coordinated with an intermediate geometry between trigonal-bipyramidal and square-pyramidal (~= 0.40). The EPR spectra in frozen solution samples are in accordance with a stable coordinate pattern for the metal centre of ligand L 1 , yielding a rhombic distorted complex with axial compression in solution, in agreement with the X-ray crystal structure of [CuL 1 ](ClO 4 ) 2 . For the binuclear complexes of L 2 and L 3 , the Cu(II) centres in solution can be distorted from their tetragonally elongated structures via interaction with ethanol and/or the nitrate counterion, leading to more than one species.

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“…Since the exceptionally active catalysts based on iron and cobalt which convert both ethylene and olefins to high molar mass polymers [between 3.7×10 6 and 2.1× 10 7 g (mol of Fe)…”

Section: Introductionmentioning

confidence: 99%

“…Following this discovery, a great deal of efforts have been dedicated to investigating the nature of the active species [6][7][8][9] by designing new analogous catalysts. [10][11][12][13][14] In this paper, we aim to introduce a new kind of mono(imino)pyridine cobalt ethylene oligomerization catalyst which is an interesting contrast to the previous iron and cobalt catalysts bearing 2,6-bis(imino)pyridine ligand.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Ethylene Oligomerization Catalytic Activity of {2‐Carbethoxy‐6‐[1‐[(2,6‐diethyl‐phenyl)imino]ethyl]pyridine}CoCl₂

Sun

Zhao²,

Gao

2007

Chin. J. Chem.

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The unsymmetric precursor ethyl 6-acetylpyridine-2-carboxylate (4) was synthesized from 2,6-dimethylpyridine (1). On the basis of this precursor, a new mono(imino)pyridine ligand (5) and the corresponding Co(II) complex {2-carbethoxy-6-[1-[(2,6-diethylphenyl)imino]ethyl]pyridine}CoCl 2 (6) were prepared. The crystal structure of complex indicates that the 2-carbethoxy-6-iminopyridine is coordinated to the cobalt as a tridentate ligand using [N, N, O] atoms, and the coordination geometry of the central cobalt is a distorted trigonal bipyramid, with the pyridyl nitrogen atom and the two chlorine atoms forming the equatorial plane. Being applied to the ethylene oligomerization, this cobalt complex shows catalytic activity of 1.820×10 4 g/mol-Co•h at 101325 Pa of ethylene at 15.5 ℃ for 1 h, when 1000 equiv. of methylaluminoxane (MAO) is employed as the cocatalyst.

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Molecular and Electronic Structures of Bis(pyridine-2,6-diimine)metal Complexes [ML₂](PF₆)_n (n = 0, 1, 2, 3; M = Mn, Fe, Co, Ni, Cu, Zn)

Cited by 326 publications

References 46 publications

Coordination Algorithms Control Molecular Architecture: [Cu^I₄(L2)₄]⁴⁺ Grid Complex Versus [M^II₂(L2)₂X₄]^y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [Fe^II(L2)₃][Cl₃Fe^IIIOFe^IIICl₃]

Coordination Algorithms Control Molecular Architecture: [Cu^I₄(L2)₄]⁴⁺ Grid Complex Versus [M^II₂(L2)₂X₄]^y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [Fe^II(L2)₃][Cl₃Fe^IIIOFe^IIICl₃]

Copper complexes with bibracchial lariat ethers: from mono- to binuclear structures

Crystal Structure and Ethylene Oligomerization Catalytic Activity of {2‐Carbethoxy‐6‐[1‐[(2,6‐diethyl‐phenyl)imino]ethyl]pyridine}CoCl₂

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Molecular and Electronic Structures of Bis(pyridine-2,6-diimine)metal Complexes [ML2](PF6)n (n = 0, 1, 2, 3; M = Mn, Fe, Co, Ni, Cu, Zn)

Cited by 326 publications

References 46 publications

Coordination Algorithms Control Molecular Architecture: [CuI4(L2)4]4+ Grid Complex Versus [MII2(L2)2X4]y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [FeII(L2)3][Cl3FeIIIOFeIIICl3]

Coordination Algorithms Control Molecular Architecture: [CuI4(L2)4]4+ Grid Complex Versus [MII2(L2)2X4]y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [FeII(L2)3][Cl3FeIIIOFeIIICl3]

Copper complexes with bibracchial lariat ethers: from mono- to binuclear structures

Crystal Structure and Ethylene Oligomerization Catalytic Activity of {2‐Carbethoxy‐6‐[1‐[(2,6‐diethyl‐phenyl)imino]ethyl]pyridine}CoCl2

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Molecular and Electronic Structures of Bis(pyridine-2,6-diimine)metal Complexes [ML₂](PF₆)_n (n = 0, 1, 2, 3; M = Mn, Fe, Co, Ni, Cu, Zn)

Coordination Algorithms Control Molecular Architecture: [Cu^I₄(L2)₄]⁴⁺ Grid Complex Versus [M^II₂(L2)₂X₄]^y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [Fe^II(L2)₃][Cl₃Fe^IIIOFe^IIICl₃]

Coordination Algorithms Control Molecular Architecture: [Cu^I₄(L2)₄]⁴⁺ Grid Complex Versus [M^II₂(L2)₂X₄]^y+ Side‐By‐Side Complexes (M=Mn, Co, Ni, Zn; X=Solvent or Anion) and [Fe^II(L2)₃][Cl₃Fe^IIIOFe^IIICl₃]

Crystal Structure and Ethylene Oligomerization Catalytic Activity of {2‐Carbethoxy‐6‐[1‐[(2,6‐diethyl‐phenyl)imino]ethyl]pyridine}CoCl₂