Synthesis and Characterization of Bis(.mu.-oxo)dimanganese(III,III), -(III,IV), and -(IV,IV) Complexes with Ligands Related to N,N'-Bis(2-pyridylmethyl)-1,2-ethanediamine (Bispicen)

Glerup, Jørgen; Goodson, Patricia A.; Hazell, Alan; Hazell, Rita G.; Hodgson, Derek J.; McKenzie, Christine J.; Michelsen, Kirsten; Rychłewska, Urszula; Toftlund, Hans

doi:10.1021/ic00096a040

Cited by 106 publications

(94 citation statements)

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“…This value is close to that found for [Mn 2 O 2 (bispicMe 2 en) 2 ](ClO 4 ) 3 .H 2 O (J ϭ Ϫ320 cm Ϫ1 ) [11] and [Mn 2 O 2 (bpy) 4 ](ClO 4 ) 3 .2H 2 O (J ϭ Ϫ300 ± 14 cm Ϫ1 ) [15] but clearly smaller than that of the strongest antiferromagnetic couplings,…”

Section: Resultssupporting

confidence: 86%

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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Section: Resultssupporting

confidence: 86%

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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“…It is likely that during the 3!4 reaction step the carboxylate arms are concomitantly displaced to accommodate the two m-oxo ligands. Thus, an arrangement similar to other, known bis(moxo)-dimanganese complexes of linear N 4 bispicen-based [11] ligands (Mn···Mn = 2.7 ) [12][13][14] is achieved. The anticipated facile oxidation of 3 (oxidase activity) can be invoked to explain the slightly different curve shape in the first evolution step (the front of the peak shows a spike, which indicates an initial rapid reduction in O 2 concentration).…”

supporting

confidence: 56%

Water Oxidation Catalyzed by a Dinuclear Mn Complex: A Functional Model for the Oxygen‐Evolving Center of Photosystem II

2005

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“…Using the same procedure, Mikata et al very recently isolated such complexes in yields of around 30 % with linear tetradentate quinoline ligands (N,N'-bis(2-quinolylmethyl)-N,N'-diethyl-ethylenediamine and its isopropyl analogue). [30] In 1994, Hodgson et al [28] published the synthesis of the complex of the ligand bispicMe 2 III Mn IV complex with sodium thiosulfate with a yield of 40 %. Finally, Moro-oka et al described the synthesis of the complex of the iprtpzb (isopropyltrispyrazolylborate) ligand by oxidation of the bis(m-hydroxo) bis-manganese(II) complex either by oxygen or electrochemically with yields of around 50 %.…”

Section: Mnmentioning

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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Synthesis and Characterization of Bis(.mu.-oxo)dimanganese(III,III), -(III,IV), and -(IV,IV) Complexes with Ligands Related to N,N'-Bis(2-pyridylmethyl)-1,2-ethanediamine (Bispicen)

Cited by 106 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)

Water Oxidation Catalyzed by a Dinuclear Mn Complex: A Functional Model for the Oxygen‐Evolving Center of Photosystem II

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

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