Synthesis, Properties, and Structures of Chromium(VI) and Chromium(V) Complexes with Heterocyclic Nitrogen Ligands

Levason, William; Reid, Gillian; Zhang, Wenjian

doi:10.1002/zaac.201300482

Cited by 7 publications

(5 citation statements)

References 31 publications

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“…The IR spectrum of the [Cr V Cl 2 (phen)(O)] + product displayed ν(Cr =O) at 945 cm –1 . This frequency is close to that reported for the [Cr V (phen)Cl 3 (O)] complex 25 . It is worth mentioning that the complex [Cr V (phen)Cl 3 O] has a crimson color, whereas the chromium(V) reported here is light brown.…”

Section: Resultssupporting

confidence: 90%

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Kinetics and mechanism of the one‐step, two‐electron oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) chloride dihydrate by periodate to chromium(V) in aqueous acidic solutions

Eltahir

Ali

Sulfab

2021

Int J of Chemical Kinetics

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The kinetics of oxidation of [CrIIICl2(phen)(H2O)2]Cl⋅2H2O (phen = 1,10‐phenanthroline) by periodate {I(VII)} have been studied in aqueous acidic solutions. The oxidation product has been isolated and characterized by elemental analysis, IR, and ESR as [CrVCl2(phen)(O)]Cl⋅1.5H2O. Under pseudo–first‐order conditions, the reaction showed first‐order dependence on the initial Cr(III) complex concentration. At fixed reaction conditions, the dependence of kobs on [I(VII)] showed saturation kinetics. The rate constant, kobs, increased with increasing pH, indicating that the hydroxo form of the chromium(III) complex is the most reactive species. A plot of kobs([H+] + K1) versus [H+] is linear with an intercept, indicating that the reaction proceeds via two parallel pathways. One pathway is independent of [H+] and the other on [H+]–1. Since water is known to be a very weak bridging ligand, the pathway involving the aqua form of the complex, almost certainly, is bridged to periodate via the chloro ligand of the chromium(III) complex. The thermodynamic parameters of the processes involved are reported. A one‐step two‐electron transfer via an inner‐sphere mechanism has been assigned to the two pathways based on the form of the rate law

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Section: Resultssupporting

confidence: 90%

“…Recently the synthesis of the complexes [Cr V (dipy)Cl 3 O] and [Cr V (phen)Cl 3 O] has also been reported 25 . The structure of the dipy complex has also been resolved by x‐ray crystallography 25 and was found to have an octahedral structure.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of the one‐step, two‐electron oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) chloride dihydrate by periodate to chromium(V) in aqueous acidic solutions

Eltahir

Ali

Sulfab

2021

Int J of Chemical Kinetics

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“…Due to its mathematical simplicity, the Bohart-Adams model has been used in many adsorption process-modeling studies. The Bohart-Adams model used for the description of the initial part of the breakthrough curve was based on surface reaction theory and mass transfer, assuming that the adsorption rate was proportional to both the adsorbent's residual capacity and the adsorbate's concentration [21][22][23]:…”

Section: The Bohart-adams Modelmentioning

confidence: 99%

Water Cleaning by a Continuous Fixed-Bed Column for Cr(VI) Eco-Adsorption with Green Adsorbent-Based Biomass: An Experimental Modeling Study

et al. 2023

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In this study, chromate adsorption onto red peanut skin (RPS) was investigated in a fixed-bed column; FTIR, PZC, SEM, DLS, and BET were used to evaluate its adsorption properties. The experiments were conducted to determine the effect of physical parameters, including the inlet initial Cr(VI) concentration (100–500 mg L−1), bed height (10–20 cm), and feed flow rate (13.59–23.45 mL min−1). They were carried out to predict breakthrough curves. The adsorption capacity coefficients were determined using the most widely used Bohart–Adams model. It was tested to fit experimental data, for a better understand the dynamic behavior, and for further optimize column performance. It was found that the Cr(VI) uptake decreases when increasing the flow rate and that high chromate concentration and bed height consequently increase the column’s life span. A high column adsorption capacity can be achieved with a higher Cr(VI) concentration due to the higher driving force. The results indicated that the Bohart–Adams model provides a good description (R2 > 0.98) of the experimental data of the Cr(VI)’s removal from the aqueous solution on the RPS suggesting that the surface diffusion is the rate-limiting step in the continues adsorption process.. Breakthrough adsorption capacity is crucial for comparing RPS with other similar materials. Indeed, possible mechanisms have been suggested for illustrating adsorption onto RPS. The obtained results showed significant potential of 26.23 mg g−1 of RPS on Cr(VI) elimination at a natural pH of 5.35. Furthermore, this global investigation allowed for the design of a promising low-cost material for the future scale-up of cleaning wastewater polluted by metal and determine the properly conditions for operating column adsorption. This material provides an economical, efficient means of eliminating pollutants, thus meeting the main aims of the UN Sustainable Development Goals (UN SDGs).

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“…The oxide chlorides, CrO 2 Cl 2 and CrOCl 3 , are immediately reduced by thioethers, 84 and the only high valent chromium complex appears to be the chromium(V) imido species, [Cr (N t Bu)Cl 2 ([9] ([18]aneS 6 )], with even the higher denticity macrocycles failing to displace chloride from the precursor. Thus in each complex the macrocycle occupies three sites on one face of the octahedron.…”

Section: Chromiummentioning

confidence: 99%

“…The oxide chlorides, CrO2Cl2 and CrOCl3, are immediately reduced by thioethers, 84 [14]aneS4)]PF6 (X = Cl or Br) have been determined (Fig. 43).…”

Section: Chromiummentioning

confidence: 99%

Developments in the chemistry of the hard early metals (Groups 1–6) with thioether, selenoether and telluroether ligands

2016

Self Cite

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The coordination chemistry of neutral thio-, seleno-and telluroether ligands towards the hard s-block, f-block and higher oxidation state early d-block metals has developed significantly over the 15 or so years. This has revealed several hitherto unknown classes of complexes and new insights into the chemistries of these hard-soft metal-ligand combinations. This Perspective describes the synthetic routes used to access such complexes and draws out their key structural features and spectroscopic properties. Where appropriate, applications of these species are also highlighted, including their use as single source precursors for the chemical vapour deposition of semiconducting metal chalcogenide thin films and as pre-catalysts for olefin polymerisation reactions. IntroductionThioether and selenoether ligands, which are neutral sulfur and selenium donors respectively, were for many years viewed as modest σ-donor ligands that formed complexes with the softer later d-block elements in low or medium oxidation states, or with post transition metals such as silver or mercury.1,2Complexes of the early d-block metals were mostly limited to low valent organometallics or carbonyls. The chemistry of telluroethers was very little explored, in major part a reflection of their limited availability and, for the alkyl telluroethers in particular, their extremely malodorous nature. 2,3The R2Te ligands are also oxygen sensitive (in contrast to the air stable R2S or R2Se), modest reducing agents and prone to cleavage of the CTe bond upon reaction with some metal centres. Even today, their chemistry remains much less extensive than that of their lighter analogues. 4 Major developments in the syntheses and coordination chemistry of macrocyclic thioethers considerably extended the range and stability of complexes containing metal centres across the d-block. More recent work has resulted in complexes of chalcogenoethers with many of the p-block elements,

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Synthesis, Properties, and Structures of Chromium(VI) and Chromium(V) Complexes with Heterocyclic Nitrogen Ligands

Cited by 7 publications

References 31 publications

Kinetics and mechanism of the one‐step, two‐electron oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) chloride dihydrate by periodate to chromium(V) in aqueous acidic solutions

Kinetics and mechanism of the one‐step, two‐electron oxidation of diaquadichloro(1,10‐phenanthroline)chromium(III) chloride dihydrate by periodate to chromium(V) in aqueous acidic solutions

Water Cleaning by a Continuous Fixed-Bed Column for Cr(VI) Eco-Adsorption with Green Adsorbent-Based Biomass: An Experimental Modeling Study

Developments in the chemistry of the hard early metals (Groups 1–6) with thioether, selenoether and telluroether ligands

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