Vibrational assignment and structure of trinuclear oxo-centered of basic formate iron(III) and chromium(III) complexes: A density functional theory study

Kiana, Samaneh; Yazdanbakhsh, Mohammad; Jamialahmadi, Mina; Tayyari, Sayyed Faramarz

doi:10.1016/j.saa.2014.03.130

Cited by 5 publications

(3 citation statements)

References 41 publications

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“…Instead, two new bands in the range of 1530-1520 cm −1 and 1420 cm −1 are observed attributed to ν as (−COO − ) and ν s (−COO − ), respectively (Figure 2). The difference between the two vibrations is 112 (1) and 103 (2) cm −1 and is consistent with the presence of a bridging deprotonated carboxyl function in the ionophores structure [34][35][36]. The strong absorption peaks at ca.…”

Section: Ir Spectroscopysupporting

confidence: 72%

Experimental and DFT Study of Monensinate and Salinomycinate Complexes Containing {Fe3(µ3–O)}7+ Core

Petkov,

Tadjer,

Encheva

et al. 2024

Molecules

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Two trinuclear oxo-centred iron(III) coordination compounds of monensic and salinomycinic acids (HL) were synthesized and their spectral properties were studied using physicochemical/thermal methods (FT–IR, TG–DTA, TG–MS, EPR, Mössbauer spectroscopy, powder XRD) and elemental analysis. The data suggested the formation of [Fe3(µ3–O)L3(OH)4] and the probable complex structures were modelled using the DFT method. The computed spectral parameters of the optimized constructs were compared to the experimentally measured ones. In each complex, three metal centres were joined together at the axial position by a μ3–O unit to form a {Fe3O}7+ core. The antibiotics monoanions served as bidentate ligands through the carboxylate and hydroxyl groups located at the termini. The carboxylate moieties played a dual role bridging each two metal centres. Hydroxide anions secured the overall neutral character of the coordination species. Mössbauer spectra displayed asymmetric quadrupole doublets that were consistent with the existence of two types of high-spin iron(III) sites with different environments—two Fe[O5] and one Fe[O6] centres. The solid-state EPR studies confirmed the +3 oxidation state of iron with a total spin St = 5/2 per trinuclear cluster. The studied complexes are the first iron(III) coordination compounds of monensin and salinomycin reported so far.

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Section: Ir Spectroscopysupporting

confidence: 72%

Experimental and DFT Study of Monensinate and Salinomycinate Complexes Containing {Fe3(µ3–O)}7+ Core

Petkov,

Tadjer,

Encheva

et al. 2024

Molecules

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“…Furthermore, in the IR spectrum of I (Figure ) the absorption bands corresponding to ν(WO) and ν(W–O–W) of CoW 12 appeared at 935 and 873 cm –1 , respectively, and were largely red-shifted from those of pristine CoW 12 (ν(WO): 945 cm –1 and ν(W–O–W): 877 cm –1 ). On the other hand, ν(Cr 3 –O) bands of Cr-CN in I appeared at 660 cm –1 and were largely blue-shifted from those of pristine Cr-CN (652 cm –1 ). , These results suggest that upon forming I the W–O bonds in CoW 12 are weakened due to the increased electron density, while the Cr 3 –O bonds in Cr-CN are strengthened due to the decreased electron density. , These observations, together with the XPS results (Figure ), confirm that charge transfer occurs from Cr-CN to CoW 12 in I . We postulate that the synergetic OER catalysis in I originates from this charge transfer, leading to the increased electron density and upshifted Fermi level of CoW 12 , which enables the OER catalysis of I . − So far, the enhanced OER activity of Co-POM-based nanocomposites has been believed to be attributable to synergetic effects involving a redistribution of electrons in the nanocomposites, but the mechanistic detail remains unclear. , We have experimentally demonstrated that the charge transfer from Cr-CN to CoW 12 is an important factor for understanding the synergetic OER catalysis of I .…”

Section: Resultssupporting

confidence: 53%

“…19,34 On the other hand, as shown in Figure 4b and c and were largely blue-shifted from those of pristine Cr-CN (652 cm −1 ). 35,36 These results suggest that upon forming I the W−O bonds in CoW 12 are weakened due to the increased electron density, while the Cr 3 −O bonds in Cr-CN are strengthened due to the decreased electron density. 37,38 These observations, together with the XPS results (Figure 4), confirm that charge transfer occurs from Cr-CN to CoW 12 in I.…”

Section: ■ Introductionmentioning

confidence: 89%

Oxygen Evolution Reaction Driven by Charge Transfer from a Cr Complex to Co-Containing Polyoxometalate in a Porous Ionic Crystal

et al. 2022

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Considerable efforts have been devoted to developing oxygen evolution reaction (OER) catalysts based on transition metal oxides. Polyoxometalates (POMs) can be regarded as model compounds of transition metal oxides, and cobalt-containing POMs (Co-POMs) have received significant interest as candidates. Nanocomposites based on Co-POMs have been reported to show high OER activities due to synergistic effects among the components; however, the role of each component is unclear due to its complex structure. Herein, we utilize porous ionic crystals (PICs) based on Co-POMs, which enable a composition–structure–function relationship to be established to understand the origin of the synergistic catalysis. Specifically, a Keggin-type POM [α-CoW12O40]6– and a Cr complex [Cr3O(OOCCH2CN)6(H2O)3]+ are implemented as PIC building blocks for the OER under nonbasic conditions. The potentially OER-active but highly soluble [α-CoW12O40]6– was successfully anchored in the crystalline PIC matrix via Coulomb interactions and hydrogen bonding induced by polar cyano groups of the Cr complex. The PIC exhibits efficient and sustained OER catalytic activity, while each building block is inactive. The Tafel slope of the linear sweep voltammetry curve and the relatively large kinetic isotope effect value suggest that elementary steps closely related to the OER rate involve single-electron and proton transfer reactions. Electrochemical and spectroscopic studies clearly show that the synergistic catalysis originates from the charge transfer from the Cr complex to [α-CoW12O40]6–; the increased electron density of [α-CoW12O40]6– may increase its basicity and accelerate proton abstraction as well as enhance electron transfer to stabilize the reaction intermediates adsorbed on [α-CoW12O40]6–.

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Coordination behavior of 3-amino-5,5′-dimethylhydantoin towards Ni(II) and Zn(II) ions: Synthesis, spectral characterization and DFT calculations

Georgieva

Todorov

Bezfamilnyi

et al. 2018

Journal of Molecular Structure

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Vibrational assignment and structure of trinuclear oxo-centered of basic formate iron(III) and chromium(III) complexes: A density functional theory study

Cited by 5 publications

References 41 publications

Experimental and DFT Study of Monensinate and Salinomycinate Complexes Containing {Fe3(µ3–O)}7+ Core

Experimental and DFT Study of Monensinate and Salinomycinate Complexes Containing {Fe3(µ3–O)}7+ Core

Oxygen Evolution Reaction Driven by Charge Transfer from a Cr Complex to Co-Containing Polyoxometalate in a Porous Ionic Crystal

Coordination behavior of 3-amino-5,5′-dimethylhydantoin towards Ni(II) and Zn(II) ions: Synthesis, spectral characterization and DFT calculations

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