Estudo potenciométrico sobre a formação de complexos no sistema ferro (III)/azoteto, em meio não totalmente aquoso

Pimenta, Adriano César

doi:10.11606/t.59.2006.tde-06112006-075106

Cited by 3 publications

(3 citation statements)

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“…4, at a ligand concentration close to that considered ideal in aqueous medium (500 mmol L -1 ), the presence of ethanol only brought about a small increase to absorbance values, making the aqueous medium the most promising for the accomplishment of the measurements. The use of solvents such as acetone and tetrahydrofuran did not provide the solvatochromic effects for the present chromium(III)/azide system, as observed previously [9][10][11][12].…”

Section: Resultssupporting

confidence: 56%

“…Azide and thiocyanate complexes of several metallic cations have been systematically studied in our laboratories with a view to understanding their coordination chemistry (equilibria) [1][2][3] and developing their analytical applications [4][5][6][7][8][9][10][11][12]. There is great analogy between the azide and the thiocyanate ligands (pseudohalides), since they develop the same red color in acid solution containing iron(III).…”

Section: Introductionmentioning

confidence: 99%

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Spectrophotometric study of the chromium(III)/azide system in the ultraviolet region and its analytical application

et al. 2006

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A sensitive and alternative method for the spectrophotometric determination ofchromium(III) based on the formation of chromium(III)/azide complexes was established byinvestigating a new band in the ultraviolet region. The best experimental conditions for the analyticaldetermination of this metallic ion were: ligand and perchloric acid analytical concentration = 493 and12.0 mmol L -1 , respectively; aqueous medium; T = 25.0 oC; contact time = 1 hour. The maximummolar absorptivity coefficient occurred at 287 nm (average 1.481 ± 0.008 × 10 4 L mol -1 cm -1 ), leadingto the determination of metal ion concentrations one hundred times lower than the ones formerlydetermined in the visible region. The system obeys Beer’s Law and is suitable for chromiumdetermination in the 0.702-2.81 mg L -1 concentration range (15-65% T, 1.00 cm-width quartz cells).Analytical applications of the current method were tested with a nutritional supplement containingchromium. Results were compared with those obtained with atomic absorption spectrometry.

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Section: Resultssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Spectrophotometric study of the chromium(III)/azide system in the ultraviolet region and its analytical application

et al. 2006

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“…Studies on complexes formation, their respective stabilities (equilibria) and/or analytical utilization have been accomplished in a systematic way in some laboratories, especially when systems involving pseudohalide or halide ligands with transition metal cations [1][2][3][4][5][6][7][8][9][10][11][12][13] are concerned. The intense red colour characteristic of the compounds formed between iron(III) and thiocyanate ions in acidic aqueous medium is one of the strongest evidences of the chemical analogy existing between these species (SCN -) and azide (N 3 ) ligands.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric study of iron oxidation in the iron(II)/thiocyanate/acetone system and some analytical applications

Martins¹,

Andrade²,

Pimenta³

et al. 2005

Eclet. Quim.

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The possibility of using thiocyanate to determine iron(II) and/or iron(III) in water-acetone mixturehas been re-examined as part of a systematic and comparative study involving metallic complexes ofpseudohalide ligands. Some parameters that affect the complete oxidation of the ferrous cations, theirsubsequent complexation and the system stability have been studied to optimize the experimental conditions.Our results show the viability and potentiality of this simply methodology as an alternative analytical procedureto determine iron cations with high sensitivity, precision and accuracy. Studies on the calibration, stability,precision, and effect of various different ions have been carried out by using absorbance values measured at480 nm. The analytical curve for the total iron determination obeys Beer’s law (r = 0.9993), showing a highersensitivity (molar absorptivity of 2.10x10 4 L cm -1 mol -1 ) when compared with other traditional systems (ligands)or even with the “similar” azide ion [1.53x10 4 L cm -1 mol -1 , for iron–III/azide complexes, in 70% (v/v)tetrahydrofuran/water, at 396 nm]. Under such optimized experimental conditions, it is possible to determineiron in the concentration range from 0.5 to 2 ppm (15-65% T for older equipments, quartz cells of 1.00 cm).

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Potentiometric Study of Azide Complexes of Iron(III) in Water/THF Medium

Pimenta¹,

Balbo²,

Oliveira³

et al. 2017

Orbital: Electron. J. Chem.

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Estudo potenciométrico sobre a formação de complexos no sistema ferro (III)/azoteto, em meio não totalmente aquoso

Cited by 3 publications

References 0 publications

Spectrophotometric study of the chromium(III)/azide system in the ultraviolet region and its analytical application

Spectrophotometric study of the chromium(III)/azide system in the ultraviolet region and its analytical application

Spectrophotometric study of iron oxidation in the iron(II)/thiocyanate/acetone system and some analytical applications

Potentiometric Study of Azide Complexes of Iron(III) in Water/THF Medium

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