Abstract
The oxidation of a ternary complex of chromium(III), [CrIII(DPA)(Mal)(H2O)2]−, involving dipicolinic acid (DPA) as primary ligand and malonic acid (Mal) as co-ligand, was investigated in aqueous acidic medium. The periodate oxidation kinetics of [CrIII(DPA)(Mal)(H2O)2]− to give Cr(VI) under pseudo-first-order conditions were studied at various pH, ionic strength and temperature values. The kinetic equation was found to be as follows: \( {\text{Rate}} = {{\left[ {{\text{IO}}_{4}^{ - } } \right]\left[ {{\text{Cr}}^{\text{III}} } \right]_{\text{T}} \left( {{{k_{5} K_{5} + k_{6} K_{4} K_{6} } \mathord{\left/ {\vphantom {{k_{5} K_{5} + k_{6} K_{4} K_{6} } {\left[ {{\text{H}}^{ + } } \right]}}} \right. \kern-0pt} {\left[ {{\text{H}}^{ + } } \right]}}} \right)} \mathord{\left/ {\vphantom {{\left[ {{\text{IO}}_{4}^{ - } } \right]\left[ {{\text{Cr}}^{\text{III}} } \right]_{\text{T}} \left( {{{k_{5} K_{5} + k_{6} K_{4} K_{6} } \mathord{\left/ {\vphantom {{k_{5} K_{5} + k_{6} K_{4} K_{6} } {\left[ {{\text{H}}^{ + } } \right]}}} \right. \kern-0pt} {\left[ {{\text{H}}^{ + } } \right]}}} \right)} {\left\{ {\left( {\left[ {{\text{H}}^{ + } } \right] + K_{4} } \right) + \left( {K_{5} \left[ {{\text{H}}^{ + } } \right] + K_{6} K_{4} } \right)\left[ {{\text{IO}}_{4}^{ - } } \right]} \right\}}}} \right. \kern-0pt} {\left\{ {\left( {\left[ {{\text{H}}^{ + } } \right] + K_{4} } \right) + \left( {K_{5} \left[ {{\text{H}}^{ + } } \right] + K_{6} K_{4} } \right)\left[ {{\text{IO}}_{4}^{ - } } \right]} \right\}}} \) where k 6 (3.65 × 10−3 s−1) represents the electron transfer reaction rate constant and K 4 (4.60 × 10−4 mol dm−3) represents the dissociation constant for the reaction \( \left[ {{\text{Cr}}^{\text{III}} \left( {\text{DPA}} \right)\left( {\text{Mal}} \right)\left( {{\text{H}}_{2} {\text{O}}} \right)_{2} } \right]^{ - } \rightleftharpoons \left[ {{\text{Cr}}^{\text{III}} \left( {\text{DPA}} \right)\left( {\text{Mal}} \right)\left( {{\text{H}}_{2} {\text{O}}} \right)\left( {\text{OH}} \right)} \right]^{2 - } + {\text{H}}^{ + } \) and K 5 (1.87 mol−1 dm3) and K 6 (22.83 mol−1 dm3) represent the pre-equilibrium formation constants at 30 °C and I = 0.2 mol dm−3. Hexadecyltrimethylammonium bromide (CTAB) was found to enhance the reaction rate, whereas sodium dodecyl sulfate (SDS) had no effect. The thermodynamic activation parameters were estimated, and the oxidation is proposed to proceed via an inner-sphere mechanism involving the coordination of IO4 − to Cr(III).
Similar content being viewed by others
References
Woodward MP, Youngy WW, Bloodgood RA (1985) J Immunol Methods 78:143
Symons MCR (1955) J Chem Soc, 2794–2796. doi:10.1039/JR9550002794
Abdel-Khalek AA, Elsemongy MM (1989) Trans Met Chem 14:206
Ewais HA, Dahman FD, Abdel-Khalek AA (2009) Central J Chem 3:3
Hassan HA, Otaibi FD, Abdel-Khalek AA (2006) Inorg React Mech 6:39
Ewais HA, Al-Orabi RO, Abdulla AY (2016) Trans Met Chem 41:427
EL-Ziri FR, Sulfab Y (1977) Inorg Chim Acta 25:15
Ewais HA, Ismail IMI, Qusti AH, Abdel-Khalek AA (2013) Oxid Commun 36:601
Abdel-Khalek AA, Elsmongy MM (1988) Bull Chem Soc Jpn 61:4407
Abdel-Hady AM (2000) Trans Met Chem 25:437
Hassan ES, Abdel-Khalek AA (2007) Inorg React Mech 6:247
Ewais HA, Habib MA, Elroby SAK (2010) Trans Met Chem 35:73
Levina A, Codd R, Dillon CT (2003) Prog Inorg Chem 51:145
Levina A, Lay PA (2005) Coord Chem Rev 249:281
Wilkins RG (1991) Kinetics and mechanism of reactions of transition metal complexes, 2nd edn. VCH Publishers Inc, NewYork
Rodrıguez A, Del Mar Graciani M, Balahura R, Moy’a ML (1996) J Phys Chem 100:16978
Ewais HA (2002) Trans Met Chem 27:562
Lever ABP (1984) Inorganic electronic spectroscopy. Elsevier, Amsterdam
Hadinec I, Jensovsky L, Linek A, Synecek V (1960) Naturwiss 47:377
Ray P (1975) Inorg Synth 5:201
Crouthamel CE, Hayes AM (1951) J Am Chem Soc Jpn 73:82
Kassim AY, Sulfab Y (1977) Inorg Chim Acta 22:169
Ali IH, Sulfab Y (2011) Inter J Chem Kinet 43:563
Fedler JH, Fendler EJ (1975) Catalysis in micellar and macromolecules systems. Academic Press, New York
Weaver MJ, Yee EL (1980) Inorg Chem 19:1936
Mcardle JV, Coyle CL, Gray HB, Yoneda CS, Howerda RA (1977) J Am Chem Soc 99:2483
Wherland S, Gray HB (1977) In: Dolphin D (ed) Biological aspects of inorganic chemistry. Wiley, New York, p 189
Menger FM, Portnoy CE (1967) J Am Chem Soc 89:4698
Al-Awadi N, Wiliams AJ (1999) Org Chem 55:4359
Acknowledgments
This work was supported by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, under Grant No. (130–663–D1435). The authors, therefore, gratefully acknowledge the DSR technical and financial support.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Basaleh, A.S., Abdel-Salam, A.H. Inner-sphere oxidation of a ternary dipicolinatochromium(III) complex involving a malonic acid co-ligand. Transit Met Chem 41, 713–719 (2016). https://doi.org/10.1007/s11243-016-0073-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11243-016-0073-0