Kinetics and Mechanistic Study on the Reaction of Iodo(diethylenetriamine) Platinum(ii) with l-Cystine

Trilochan Swain; Prakash Mohanty

doi:10.1071/CH08192

RESEARCH ARTICLE

Previous Contents Vol 62(5)

Kinetics and Mechanistic Study on the Reaction of Iodo(diethylenetriamine) Platinum(ii) with l-Cystine

Trilochan Swain ^A ^C and Prakash Mohanty ^B

+ Author Affiliations

- Author Affiliations

^A Faculty of Chemistry, Indic Institute of Design and Research, Orissa, India.

^B Department of Chemistry, Utkal University, Bhubaneswar-751 004, Orissa, India.

^C Corresponding author. Email: scienceorissa@rediffmail.com

Australian Journal of Chemistry 62(5) 493-500 https://doi.org/10.1071/CH08192
Submitted: 5 May 2008 Accepted: 19 December 2008 Published: 15 May 2009

Abstract

Substitution reactions of the complex [Pt(dien)I]⁺, where dien = diethylenetriamine or 1,5-diamino-3-azapentane, with the sulfur-containing rescue agent l-cystine have been studied in a 1.0 × 10^–1 mol dm^–3 aqueous perchlorate medium at various temperatures (25–50°C) and pH (2.30–1.00) using a UV-visible spectrophotometer. The products were characterized by their infrared and ¹H NMR data at various temperatures. These data indicate that [Pt(dien)I]⁺ formed a complex with l-cystine through Pt–S bonds at pH 1.00–2.30. This Pt–S bond is observed at 50°C with ring closure of the dien (δ 3.8–3.9, 2H, CH₂) and with open-ring dien (δ 3.2, 3.6–3.8 (dien), 2H, CH₂). All reactions follow the rate law –d[mixture]/dt = (k₁ + k₂[Nu])[Pt^II], where k₂ denotes a second-order rate constant and [Nu] is the total concentration of nucleophile. The product formation rate constant and activation parameters E_a, ΔH^#, and ΔS^# have been determined.

Acknowledgement

The author (T.S.) thanks the Department of Chemistry, Utkal University, for providing support for the present research.

References

Kinetics and Mechanistic Study on the Reaction of Iodo(diethylenetriamine) Platinum(ii) with l-Cystine

Abstract

Acknowledgement

Subscriber Login