Vibrational spectra of carboxylato complexes—III. Trinuclear ‘basic’ acetates and formates of chromium(III), iron(III) and other transition metals

Johnson, M.K.; Powell, D.B.; Cannon, Roderick D.

doi:10.1016/0584-8539(81)80029-3

Cited by 151 publications

(58 citation statements)

References 22 publications

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“…Since this mode is Raman active we clarified by Raman analysis, where it appears at 245 cm −1 (not shown). This is in contrast to the previously reported value of 148 cm −1 [16]. One possible reason may a different spin state with larger force constant in our complex so that excitation of the stretching mode ν s occurs at higher frequency, as the larger ligand mass would tend to the opposite effect.…”

Section: Computational Detailscontrasting

confidence: 56%

Vibrational dynamics of a trinuclear oxo-bridged iron complex as studied by nuclear inelastic scattering, Mössbauer spectroscopy and DFT calculations

Rajagopalan

Asthalter

Rabe

et al. 2010

J. Phys.: Conf. Ser.

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Vibrational dynamics of a trinuclear oxo-bridged iron complex as studied by nuclear inelastic scattering, Mössbauer spectroscopy and DFT calculations IntroductionThere is a continuous interest in the search for selective metal complexes which serve as catalysts for the oxygenation of unactivated hydrocarbon substrates via polynuclear non-heme iron catalysts. The understanding on how such activation reactions work relies on the vibrational dynamics of the metal centre in the catalysts. Vibrational spectroscopy provides a sharp and clear probe of the structure, dynamics and reactivity of biological molecules. Identifying the active metal-site vibrations and relating them to the functional dynamics is of particular interest in enzymes. So far the published works by several authors were conducted on the vibrational properties of iron heme porphyrins [1] and non-heme Fe-S hydrogenase [2]. Recently, the mechanisms governing the spin crossover in Fe compounds were also reported in detail [3]. In this work, we report the first information about the vibrational dynamics of a trinuclear oxobridged iron complex (figure 1), investigated by NIS and DFT methods. The inhomogeneity of the iron coordination is determined by Mössbauer spectroscopy.

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Section: Computational Detailscontrasting

confidence: 56%

Vibrational dynamics of a trinuclear oxo-bridged iron complex as studied by nuclear inelastic scattering, Mössbauer spectroscopy and DFT calculations

Rajagopalan

Asthalter

Rabe

et al. 2010

J. Phys.: Conf. Ser.

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“…The synthetic complex has several potential benefits over the natural material: it is inexpensive to synthesize and can be readily prepared in bulk. Chromodulin is susceptible to hydrolysis, especially in the presence of acid, whereas the synthetic material can be recrystallized from dilute mineral acid [17] and could potentially survive oral ingestion. After the insulin-signaling event, chromodulin is released in the urine [18,19,20,21,22], and the body appears to target the material for excretion rather than absorption.…”

Section: Introductionmentioning

confidence: 99%

The biomimetic [Cr3O(O2CCH2CH3)6(H2O)3]+ decreases plasma insulin, cholesterol, and triglycerides in healthy and type II diabetic rats but not type I diabetic rats

et al. 2002

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The in vivo effects of administration of the synthetic, functional biomimetic cation [Cr(3)O(O(2)CCH(2)CH(3))(6)(H(2)O)(3)](+) to healthy and type I and type II diabetic model rats are described. In contrast to current chromium-containing nutrition supplements, which only serve as sources of absorbable chromium, the trinuclear cation has been shown in in vitro assays to interact with the insulin receptor, activating its kinase activity, presumably by trapping the receptor in its active conformation. Thus, treatment of rats with the trinuclear cation would be expected to result in changes in lipid and carbohydrate metabolism related to insulin action. After 24 weeks of intravenous administration (0-20 micro g Cr/kg body mass), the cation results in a concentration-dependent lowering of levels of fasting blood plasma LDL cholesterol, total cholesterol, triglycerides, and insulin and of 2-h plasma insulin and glucose levels after a glucose challenge; these results confirm a previous 12-week study examining the effect of the synthetic cation on healthy rats and are in stark contrast to those of administration of other forms of Cr(III) to rats, which have no effect on these parameters. The cation has little, if any, effect on rats with STZ-induced diabetes (a type I diabetes model). However, Zucker obese rats (a model of the early stages of type II diabetes) after 24 weeks of supplementation (20 micro g/kg) have lower fasting plasma total, HDL, and LDL cholesterol, triglycerides, and insulin levels and lower 2-h plasma insulin levels. The lowering of plasma insulin concentrations with little effect on glucose concentrations suggests that the supplement increases insulin sensitivity.

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“…1, with main bands at cm À1 : 1590 (m asym COO À ), 1423 (m sym COO), 1350 (sym bend CH 3 ), 1034 (rock CH 3 ), 662 and 618 (in plane and out-of-plane bend COO À , respectively) and at 563 (m as M 3 O). The frequency difference between the antisymmetric and symmetric stretching modes of the carboxylate group is typical of acetate ligand bridging two metal ions [10][11][12]. The redox behavior of the most soluble clusters Scheme 1.…”

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confidence: 99%

A new facile high yield preparative route for mixed-trinuclear acetate clusters

Vrubel

Hasegawa

Oliveira

et al. 2006

Inorganic Chemistry Communications

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Vibrational spectra of carboxylato complexes—III. Trinuclear ‘basic’ acetates and formates of chromium(III), iron(III) and other transition metals

Cited by 151 publications

References 22 publications

Vibrational dynamics of a trinuclear oxo-bridged iron complex as studied by nuclear inelastic scattering, Mössbauer spectroscopy and DFT calculations

Vibrational dynamics of a trinuclear oxo-bridged iron complex as studied by nuclear inelastic scattering, Mössbauer spectroscopy and DFT calculations

The biomimetic [Cr3O(O2CCH2CH3)6(H2O)3]+ decreases plasma insulin, cholesterol, and triglycerides in healthy and type II diabetic rats but not type I diabetic rats

A new facile high yield preparative route for mixed-trinuclear acetate clusters

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