A kinetic study of the reactions of dimethyl sulfide bridged tetramethylplatinum(II) and octamethylplatinum(IV) complexes with dimethyl sulfide and bidentate ligands

Katsuyuki Nakayama, Yuichi Kondo, Koji Ishihara

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Kinetics for the reactions of [1] [PtIV2Me8 (μ-SMe2)2] + 2 Me2S kfkd 2 [PtIVMe4(SMe2)2] [2] [PtII2Me4 (μ-SMe2)2] + 2 Me2S kf→ 2 [PtIIMe2(SMe2)2] and [3] [PtIV2Me8 (μ-SMe2)2] + 2NN → 2 [PtIVMe4(NN)] + 2 Me2S where NN = bipy or 4,4′-Me2-bipy, have been studied at various temperatures and pressures. Reaction [3] was shown to consist of the rapid conversion of the dimer to a monomer and the much slower subsequent substitution of the dimethyl sulfide with bidentate ligand NN: [PtIV2Me8(μ-SMe2)2] + 2 Me2S ⇌ 2 [PtIVMe4(SMe2)2] and [PtIVMe4(SMe2)2] + NN → [PtIVMe4(NN)] + 2 Me2S The rate constants and activation parameters for the reactions areas follows: kf= 3.16 ± 0.06 M-1 s-1 (25°C), ΔHf = 51.8 ± 1.7 kJ mol-1, ΔSf = -61.0 ± 5.8 J mol-1 K-1, kd= 1.18 ± 0.22 M-1 s-1 (25°C), ΔHd = 65 ± 22 kJ mol-1, ΔSd = -26 ± 73 J mol-1 K-1 for reaction [1] in n-hexane; kf = 6.68 ± 0.06 M-1 s-1 (25°C), ΔHf = 58.0 ± 3.1 kJ mol-1, ΔSf = -34.5 ± 10.5 J mol-1 K-1, ΔVf = -10.7 ± 1.3 cm3 mol-1 for reaction [2] in dichloromethane; k2= (7.09 ± 1.89) × 10-4 M-1 s-1, ΔH2 = 95 ± 21 kJ mol-1, and ΔS2 = 18 ± 70 J mol-1 K-1, ΔV2 = 9 ± 9 cm3 mol-1 for reaction [3] with bipy, and kl = (1.10 ± 0.10) × 10-2 s-1, k3/k-1 = (4.33 ± 0.30) × 10-2, and k2= (6.09 ± 1.35) × 10-4 M-1 s-1 for reaction [3] with 4,4′-Me2-bipy. It was shown that reactions [1] and [2] proceed nucleophilically without any intermediates, and reaction [3] proceeds through a mainly k2 path for NN = bipy and through both k1 and k2 paths for NN = 4,4′-Me2-bipy, without appreciable participation of the direct reaction between the dimer and NN as shown by the following reaction scheme.

Original languageEnglish
Pages (from-to)62-70
Number of pages9
JournalCanadian Journal of Chemistry
Volume76
Issue number1
DOIs
Publication statusPublished - 1998 Jan 1

Keywords

  • High-pressure kinetics
  • Octamethylplatinum(IV) dimer
  • Reaction mechanism
  • Tetramethylplatinum(II) dimer

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

Fingerprint Dive into the research topics of 'A kinetic study of the reactions of dimethyl sulfide bridged tetramethylplatinum(II) and octamethylplatinum(IV) complexes with dimethyl sulfide and bidentate ligands'. Together they form a unique fingerprint.

  • Cite this