Kinetic Study of the Dissociation of Sodium Cryptate(2,2,1)

Koji Ishihara, Hiroko Miura, Shigenobu Funahashi, Motoharu Tanaka

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9 Citations (Scopus)

Abstract

The rate of dissociation of sodium cryptate(2,2,1) (NaCry+) has been measured at various temperatures and pressures in dimethyl sulfoxide (Me2SO), N,N-dimethylformamide (DMF), and acetonitrile (MeCN) by using a high-pressure stopped-flow apparatus with conductometric detection. There are two reaction paths: an acid-independent path (kd1), CryNa+ → Cry + Na+, and an acid-dependent path (Kd2), CryNa+ + Hdca → CryH+ + Na+ + dca-, where Hdca is dichloroacetic acid. Activation parameters are as follows: in Me2SO, kd1/S-1 = (7.65 ± 0.05) × 10-1 (25 °C), ΔV‡dl/cm3 mol-1 = 2.1 ± 0.7, ΔH‡dl/kJ mol-1 = 70.4 ± 0.8, and ΔS‡d1/j mol-1 K-1 = -11 ± 3; in DMF, kd1/s-1 = (3.37 ± 0.03) × 10-1 (25 °C), kd2/mol-1 kg s-1 (25 °C), ΔV‡dl/cm3 mol-1 = 2.0 ± 0.2, ΔV‡d2/cm3 mol-1 = -8.8 ± 1.0, ΔH‡d2/kJ mol-1 = 73.0 ± 0.9, ΔH‡d2/kJ mol-1 = 30 ± 5, ΔS‡d1/J mol-1 K-1 = -9 ± 3, and ΔS‡d2/J mol-1 K-1 = -140 ± 20; in MeCN, kd2/mol-1 kg s-1 = 73.5 ± 0.5, ΔV‡d2/cm3 mol-1 = -16.0 ± 0.8, ΔH‡d2/kJ mol-1 =41.1 ± 1.3, and ΔS‡d2/J mol-1 K-1 = -71 ± 4. The reaction volume for the formation of NaCry+ in Me2SO has also been measured dilatometrically: ΔV° = 3.3 ± 0.4 cm3 mol-1. The reaction mechanism is discussed on the basis of these parameters.

Original languageEnglish
Pages (from-to)1706-1710
Number of pages5
JournalInorganic Chemistry
Volume27
Issue number10
DOIs
Publication statusPublished - 1988 Jan 1

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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