Orbital - Vol. 9 No. 5 - October - December 2017
FULL PAPERS

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

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  • Adriano Cesar Pimenta,
  • Valdir Roberto Balbo,
  • Marcelo Firmino de Oliveira,
  • Fernando Grine Martins,
  • Leandro Maranghetti Lourenço,
  • José Fernando de Andrade
Adriano Cesar Pimenta
Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto – Universidade de São Paulo– Ribeirão Preto, SP - Brazil
Valdir Roberto Balbo
Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto – Universidade de São Paulo– Ribeirão Preto, SP - Brazil
Marcelo Firmino de Oliveira
Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto – Universidade de São Paulo – Ribeirão Preto, SP - Brazil
Fernando Grine Martins
Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto – Universidade de São Paulo– Ribeirão Preto, SP - Brazil
Leandro Maranghetti Lourenço
Departamento de Química – Instituto de Ciências Exatas – Universidade Federal Fluminense – Volta Redonda, RJ – Brazil
José Fernando de Andrade
Departamento de Química - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto – Universidade de São Paulo – Ribeirão Preto, SP - Brazil
Published December 29, 2017
Keywords
  • complexes,
  • stability constants,
  • water/THF medium
How to Cite
(1)
Pimenta, A. C.; Balbo, V. R.; de Oliveira, M. F.; Martins, F. G.; Lourenço, L. M.; de Andrade, J. F. Potentiometric Study of Azide Complexes of Iron(III) in Water/THF Medium. Orbital: Electron. J. Chem. 2017, 9, 323-328.

Copyright (c) 2017 Orbital: The Electronic Journal of Chemistry

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Abstract

The stepwise formation of iron(III)-azide complexes in water/THF medium has been investigated at 20.0 (± 0.1) °C and 1.00 mol L-1 ionic strength (NaClO4). By the indirect potentiometric method employed, using a glass electrode and under the conditions studied, three mononuclear complexes were successively detected for each water/THF ratio. No evidence of polynuclear species was found. The final analyses of the data for aqueous-tetrahydrofurane (20.0-40.0%, v/v) medium, by solution of adjusted simultaneous equations with Fronaeus function values, led to the overall stability constants varying from b1 = 7.11´103 L mol-1 to b3 = 4.12´1012 L3 mol-3. The results showed that the organic solvent proportion is an important parameter for formation of these complexes. Iron complexes with higher stability were produced in the presence of 40.0% (v/v) tetrahydrofuran. Comparison with literature values suggests that the organic solvent has high influence on the coordination of the metallic ion.

DOI: http://dx.doi.org/10.17807/orbital.v9i5.970

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