Iron(II/III) complexes of non-porphyrin macrocyclic [N4]2− ligands: structure and axial reactivity

Käpplinger, Indira; Keutel, Heike; Jäger, E.

doi:10.1016/s0020-1693(99)00101-2

Cited by 15 publications

(5 citation statements)

References 31 publications

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“…As expected, the [ClO 4 ]anion has typical tetrahedral geometry where the Cl-O bond lengths and O-Cl-O angles are not equal to one another but vary with the environment around the O atoms. In the title compound, the Cl-O bond lengths vary from 1.369 (3) to 1.415 (3) Å for [Cl(1)O 4 ]anion and from 1.420 (2) to 1.440 (2) Å for [Cl(2)O 4 ]anion are comparable to that previuosly reported for the perchlorate anions (Kapplinger & Keutel, 1999). The O-Cl-O angles range from 105.4 (2) to 111.8 (4)° for the first anion and from 109.04 (15) to 110.33 (13)° for the second one.…”

Section: Data Collectionsupporting

confidence: 77%

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3-(Ammoniomethyl)pyridinium bis(perchlorate)

Bayar¹,

Kefi²,

Silva

et al. 2013

Acta Cryst E

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In the title molecular salt, C6H10N2 2+·2ClO4 −, the Cl—O bond lengths [anion 1: 1.369 (3)–1.415 (3); anion 2: 1.420 (2)–1.441 (2) Å] and the O—Cl—O angles [anion 1: 105.4 (2)–111.8 (4); anion 2: 107.8 (1)–110.3 (1)°] indicate a slight distortion of the perchlorate anions from regular tetrahedral symmetry. In the crystal, the components are linked into columns along the a-axis direction via N—H⋯O and C—H⋯O hydrogen bonds, with stacks of the organic molecules being surrounded by stacks of perchlorate anions.

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Section: Data Collectionsupporting

confidence: 77%

“…For general background to perchlorate salts with organic cations, see: Czarnecki et al (1994); Czupinski et al (2002Czupinski et al ( , 2006. For related structures, see: Kapplinger & Keutel (1999); Ye et al (2002) Experimental Crystal data…”

Section: Related Literaturementioning

confidence: 99%

3-(Ammoniomethyl)pyridinium bis(perchlorate)

Bayar¹,

Kefi²,

Silva

et al. 2013

Acta Cryst E

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“…The compression of the layers leads to shortening of two C OÁ Á ÁC O interactions. C4 O2Á Á ÁC4 O2 decreases by 0.453 Å , while C4 O2Á Á ÁC2 O1 compresses to become the shortest of its type in -GLYGLY, although still substantially longer [2.909 (7) Å ] than the shortest value observed under ambient pressure conditions [2.521 (2) Å ; Kapplinger et al, 1999].…”

Section: Figurementioning

confidence: 97%

Effect of pressure on the crystal structure of α-glycylglycine to 4.7 GPa; application of Hirshfeld surfaces to analyse contacts on increasing pressure

Moggach

Allan

Parsons

et al. 2006

Acta Crystallogr B Struct Sci

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The crystal structure of -glycylglycine (-GLYGLY) has been determined at room temperature at pressures between 1.4 and 4.7 GPa. The structure can be considered to consist of layers. The arrangement of molecules within each layer resembles the antiparallel -sheet motif observed in proteins, except that in -GLYGLY the motif is constructed through NHÁ Á ÁO hydrogen bonds rather than covalent amide links. Compression of -GLYGLY proceeds via the reduction in void sizes. Voids close in such a way as to decrease the distances of stabilizing interactions such as hydrogen bonds and dipolar contacts. The largest reductions in interaction distances tend to occur for those contacts which are longest at ambient pressure. These longer interactions are formed between the -sheet-like layers, and the largest component of the strain tensor lies in the same direction. The NÁ Á ÁO distance in one NHÁ Á ÁO hydrogen bond measures 2.624 (9) Å at 4.7 GPa. This is very short for this kind of interaction and the crystal begins to break up above 5.4 GPa, presumably as the result of a phase transition. The changes that occur have been analysed using Hirshfeld surfaces. Changes in the appearance of these surfaces enable rapid assessment of the structural changes that occur on compression.

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“…Contrary to their low significance in living systems, a large portion of the compounds reported to exhibit “catalase-like” activity are manganese complexes, mainly because of their potential application as therapeutics . Catalase models that were built around iron(III) centers were mostly based on heme-type structures; , non-heme iron complexes have been much less investigated for their catalase activity or, more general, “oxygen-activation” properties. − However, although these compounds decompose H 2 O 2 , − the notation “catalase mimic” in our view often appears to be rather euphemistic. Most of the published models have inherent serious deficiences with respect to the preferred characteristics of a “good” catalase mimic, that is, water-solubility, quantitative O 2 production obeying the stoichiometry of eq 1, catalytic activity at physiological pH values (pH 7 ± 1) and micromolar catalyst and H 2 O 2 concentrations, and low activity as oxygenating (peroxidase-like) agent .…”

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confidence: 97%