Syntheses and characterization of binuclear manganese(III,IV) and -(IV,IV) complexes with ligands related to N,N'-bis(2-pyridylmethyl)-1,2-ethanediamine

Glerup, Joergen; Hodgson, Derek J.; Michelsen, Kirsten; Weihe, Hoegni

doi:10.1021/ic00026a012

Cited by 69 publications

(32 citation statements)

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“…3ϩ complexes ( L representing a tetradentate ligand of the bispicen family) of ref [7] , for which unfortunately no structural data is available.…”

Section: Resultsmentioning

confidence: 99%

“…This can be quantitatively interpreted by antiferromagnetic coupling between a Mn(III) high spin and a Mn(IV) (J = Ϫ316 cm Ϫ1 [4] Similar complexes using linear tetradentate ligands like N,NЈ-bis(2-pyridylmethyl)-1,2-diaminoethane (bispicen) [6] have been prepared in order to study their redox properties in relation to their structures. [7] We report herein the synthesis and characterization of a new dinuclear mixed-valence di-µ-oxo manganese complex with the tetradentate ligand N,N-bis(2-pyridylmethyl)-1,2-diaminoethane (N,Nbispicen), an isomer of bispicen which presents a tertiary amino group as well as a primary amino group instead of the two secondary amino groups in bispicen. N,Nbispicen is thus a tripodal ligand similar to tris(2-pyridylmethyl)amine (TPA) [8] and tris(2-aminoethyl)-amine (tren) [9] as shown in Scheme 1. ]…”

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confidence: 99%

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Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

Horner

Charlot

Boussac

et al. 1998

Eur. J. Inorg. Chem.

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“…3ϩ complexes ( L representing a tetradentate ligand of the bispicen family) of ref [7] , for which unfortunately no structural data is available.…”

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

Horner

Charlot

Boussac

et al. 1998

Eur. J. Inorg. Chem.

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“…[53]; bpea = bis-picolylethylamine, bpy = bipyridine, phen = 1,10-phenanthroline, mesterpy = mesitylterpyridine.…”

Section: Hydrogen Peroxide Disproportionation-kinetic Studies On Dimamentioning

confidence: 99%

“…[28,31,35,[50][51][52][53] We studied the magnetic properties of complexes 1-3 to assess the influence of the peripheral tetradentate ligand on the magnetic interaction. Owing to the strong coupling for all complexes and the small range of variation, it was necessary to study the three compounds in spite of earlier measurements on 1-2.…”

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confidence: 99%

Carboxylate Ligands Drastically Enhance the Rates of Oxo Exchange and Hydrogen Peroxide Disproportionation by Oxo Manganese Compounds of Potential Biological Significance

Dubois

Pécaut

Charlot

et al. 2008

Chemistry A European J

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To mimic the carboxylate-rich active site of the manganese catalases more closely we introduced carboxylate groups into dimanganese complexes in place of nitrogen ligands. The series of dimanganese(III,IV) complexes of tripodal ligands [Mn(2)(L)(2)(O)(2)](3+/+/-/3-) was extended from those of tpa (1) and H(bpg) (2) to those of H(2)(pda) (3) and H(3)(nta) (4) (tpa=tris-picolylamine, H(bpg)=bis-picolylglycylamine, H(2)(pda)=picolyldiglycylamine, H(3)(nta)=nitrilotriacetic acid). While 3 [Mn(2)(pda)(2)(O)(2)][Na(H(2)O)(3)] could be synthesized at -20 degrees C and characterized in the solid state, 4 [Mn(2)(nta)(2)(O)(2)](3-) could be obtained and studied only in solution at -60 degrees C. A new synthetic procedure for the dimanganese(III,III) complexes was devised, using stoichiometric reduction of the dimanganese(III,IV) precursor by the benzil radical with EPR monitoring. This enabled the preparation of the parent dimanganese(III,III) complex 5 [Mn(2)(tpa)(2)(O)(2)](ClO(4))(2), which was structurally characterized. The UV/visible, IR, EPR, magnetic, and electrochemical properties of complexes 1-3 and 5 were analyzed to assess the electronic changes brought about by the carboxylate replacement of pyridine ligands. The kinetics of the oxo ligand exchanges with labeled water was examined in acetonitrile solution. A dramatic effect of the number of carboxylates was evidenced. Interestingly, the influence of the second carboxylate substitution differs from that of the first one probably because this substitution occurs on an out-of-plane coordination while the former occurs in the plane of the [Mn(2)O(2)] core. Indeed, on going from 1 to 3 the exchange rate was increased by a factor of 50. Addition of triethylamine caused a rate increase for 1, but not for 3. The abilities of 1-3 to disproportionate H(2)O(2) were assessed volumetrically. The disproportionation exhibited a sensitivity corresponding to the carboxylate substitution. These observations strongly suggest that the carboxylate ligands in 2 and 3 act as internal bases.

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“…At the X-band, both the [Mn III Ϫ(µ-O) 2 ϪMn IV ] 3ϩ [13,14] and [Mn III Ϫ(µ-O) 2 (µ-OAc)ϪMn IV ] 2ϩ [15,16] core systems present 16-line spectra that differ in their relative line intensities while the only mono(µ-oxo) complex reported in the literature, [LЈ i Mn III Ϫ(µ-O)ϪMn IV LЈ i ] 3ϩ (see Scheme 1), exhibits a peculiar 18-line spectrum. [17] In order to synthesise a new Mn III Ϫ(µ-O)ϪMn IV system, we designed a ligand very similar to the one (LЈ i H) used by Horner et al In the laboratory, we previously used these ligands in the amine form (noted L a H and LЈ a H in Scheme 1) to synthesise Fe III Ϫ (µ-O)ϪFe III systems and found that both ligands behave the same.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure and Characterisation of New Phenolato-Bridged Manganese Complexes [L2Mn2]2+ − Formation by Ligand Oxidation in LaH [LaH = N-(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine]

Hureau

Anxolabéhère‐Mallart

Nierlich

et al. 2002

Eur. J. Inorg. Chem.

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A mononuclear [L a Mn III OAc](ClO 4 )·0.5H 2 O [2(ClO 4 )·0.5H 2 O] complex with a new amino-containing pentadentate ligand L a H with a [N 4 O] coordination sphere has been obtained. Magnetic susceptibility measurements of 2(ClO 4 )·0.5H 2 O indicated a high spin electronic configuration for the Mn III ion.In cyclic voltammetry the reversible wave observed at E 1/2 = 0.15 V vs. SCE was attributed to the reduction of Mn III into Mn II . In acetonitrile solution complex 2 spontaneously evolved into phenolato-bridged Mn II Mn II dimeric complexes with the concomitant oxidation of the ligand. X-ray diffraction structures revealed that there is indeed a 1:1 mixture of two closely related complexes: in one case both ligands L a − have been oxidised to the imine form leading to the [L i Mn II Mn II L i ] 2+ cation (1a), whereas in the other, only one ligand has been oxidised, leading to the [L a Mn II Mn II L i ] 2+ cation (1b). In both 1a and 1b, Mn II ions are in a distorted octahedral environment. Crystallographic data indicated that the Mn 2 O 2 core is similar for 1a and 1b. The complete spectroscopic and electrochemical studies performed on powder

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Syntheses and characterization of binuclear manganese(III,IV) and -(IV,IV) complexes with ligands related to N,N'-bis(2-pyridylmethyl)-1,2-ethanediamine

Cited by 69 publications

References 0 publications

Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

Synthesis, Structure, Electronic, Redox, and Magnetic Properties of a New Mixed-Valent Mn-Oxo Cluster: [Mn2III,IVO2(N,Nbispicen)2]3+ (N,Nbispicen =N,N-bis(2-pyridylmethyl)-1,2-diaminoethane)

Carboxylate Ligands Drastically Enhance the Rates of Oxo Exchange and Hydrogen Peroxide Disproportionation by Oxo Manganese Compounds of Potential Biological Significance

Synthesis, Structure and Characterisation of New Phenolato-Bridged Manganese Complexes [L2Mn2]2+ − Formation by Ligand Oxidation in LaH [LaH = N-(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine]

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