A new class of bis(.mu.-aryloxy)-bridged dimers with first-row divalent transition-metal ions. Synthesis and structural characterization of the (Et4N)2[M2Cl4(O-C6H4-p-CH3)2] complexes (M = Mn(II), Fe(II), Co(II), Zn(II), and Cd(II))

Coucouvanis, D.; Greiwe, Klaus; Salifoglou, Athanasios; Challen, Paul R.; Simopoulos, A.; Kostikas, A.

doi:10.1021/ic00277a002

Cited by 40 publications

(11 citation statements)

References 4 publications

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“…Experimental Mössbauer parameters − along with our predicted isomer shifts (IS), quadrupole splitting (QS) parameters, and nuclear densities (ND) for complexes in the training set are presented in Table . A plot of experimental isomer shift δ versus ρ(0) is shown in Figure ; calculated versus experimental quadrupole splitting parameters are shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

DFT Calculations of Isomer Shifts and Quadrupole Splitting Parameters in Synthetic Iron−Oxo Complexes: Applications to Methane Monooxygenase and Ribonucleotide Reductase

et al. 2003

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To predict isomer shifts and quadrupole splitting parameters of Fe atoms in the protein active sites of methane monooxygenase and ribonucleotide reductase, a correlation between experimental isomer shifts ranging 0.1-1.5 mm s(-)(1) for Fe atoms in a training set with the corresponding density functional theory (DFT) calculated electron densities at the Fe nuclei in those complexes is established. The geometries of the species in the training set, consisting of synthetic polar monomeric and dimeric iron complexes, are taken from the Cambridge structural database. A comparison of calculated Mössbauer parameters for Fe atoms from complexes in the training set with their corresponding experimental values shows very good agreement (standard deviation of 0.11 mm/s, correlation coefficient of -0.94). However, for the Fe atoms in the active sites of the structurally characterized proteins of methane monooxygenase and ribonucleotide reductase, the calculated Mössbauer parameters deviate more from their experimentally measured values. The high correlation that exists between calculated and observed quadrupole splitting and isomer shift parameters for the synthetic complexes leads us to conclude that the main source of the error arising for the protein active sites is due to the differing degrees of atomic-level resolution for the protein structural data, compared to the synthetic complexes in the training set. Much lower X-ray resolutions associated with the former introduce uncertainty in the accuracy of several bond lengths. This is ultimately reflected in the calculated isomer shifts and quadrupole splitting parameters of the Fe sites in the proteins. For the proteins, the closest correspondence between predicted and observed Mössbauer isomer shifts follows the order MMOH(red), RNR(red), MMOH(ox), and RNR(ox), with average deviations from experiment of 0.17, 0.17, 0.17-0.20, and 0.32 mm/s, but this requires DFT geometry optimization of the iron-oxo dimer complexes.

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Section: Resultsmentioning

confidence: 99%

DFT Calculations of Isomer Shifts and Quadrupole Splitting Parameters in Synthetic Iron−Oxo Complexes: Applications to Methane Monooxygenase and Ribonucleotide Reductase

et al. 2003

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“…These values are in agreement with those reported in the literature for complexes where two Mn II ions are bridged by two phenolate ligands. [27,29,31,34] Comparable results are obtained for 1(ClO 4 ) 2 ·H 2 O: g ϭ 1.96 and J ϭ Ϫ2.9 cm Ϫ1 . Small deformations of the [Mn 2 O 2 ] diamond core unit could lead to the slight differences in the g and J values determined for compound 1, depending on the counterion.…”

Section: Magnetic Susceptibility Measurementsmentioning

confidence: 85%

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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“…[38] Later, the definite structure of complex 1 was unanimously confirmed by X-ray single crystal diffraction. of sodium salt of 2,4,6-tri-tert-butylphenol in THF was carried out at room temperature overnight (Scheme 1).…”

Section: Synthesis and Characterization Of Anionic Cobalt(ii) Aryloxidementioning

confidence: 96%

Ring‐opening Polymerization of L‐Lactide by an Anionic Cobalt(II) Aryloxide

Yuan

Zhang

et al. 2012

Chin. J. Chem.

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The reaction of anhydrous CoCl 2 with NaOAr (ArO＝2,4,6-tri-tert-butylphenoxo) in THF at room temperature in 1∶3 molar ratio afforded anionic cobalt aryloxide [Na(THF) 6 ][Co(OAr) 3 ] (1). The definite structure of this complex was characterized by X-ray single crystal diffraction. It was found that this anionic aryloxo cobalt(II) complex could effectively initiate the ring-opening polymerization of L-lactide both in solution and in bulk, leading to high molecular weight poly(L-lactide).

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A new class of bis(.mu.-aryloxy)-bridged dimers with first-row divalent transition-metal ions. Synthesis and structural characterization of the (Et4N)2[M2Cl4(O-C6H4-p-CH3)2] complexes (M = Mn(II), Fe(II), Co(II), Zn(II), and Cd(II))

Cited by 40 publications

References 4 publications

DFT Calculations of Isomer Shifts and Quadrupole Splitting Parameters in Synthetic Iron−Oxo Complexes: Applications to Methane Monooxygenase and Ribonucleotide Reductase

DFT Calculations of Isomer Shifts and Quadrupole Splitting Parameters in Synthetic Iron−Oxo Complexes: Applications to Methane Monooxygenase and Ribonucleotide Reductase

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]

Ring‐opening Polymerization of L‐Lactide by an Anionic Cobalt(II) Aryloxide

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