Dimethylsulfoxide as a Ligand for RhI and IrI Complexes - Isolation, Structure, and Reactivity Towards X-H Bonds (X = H, OH, OCH3)

Reto Dorta, Haim Rozenberg, Linda J.W. Shimon, David Milstein

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Novel neutral and cationic RhI and IrI complexes that contain only DMSO molecules as dative ligands with S-, O-, and bridging S,O-binding modes were isolated and characterized. The neutral derivatives [RhCl(DMSO)3] (1) and [IrCl(DMSO)3] (2) were synthesized from the dimeric precursors [M2Cl2(coe)4] (M = Rh, Ir; COE = cyclooctene). The dimeric IrI compound [Ir 2Cl2(DMSO)4] (3) was obtained from 2. The first example of a square-planar complex with a bidentate S,O-bridging DMSO ligand, [(coe)(DMSO)Rh-(μ-Cl)(μ-DMSO)RhCl(DMSO)] (4), was obtained by treating [Rh2Cl2(coe)4] with three equivalents of DMSO. The mixed DMSO-olefin complex [IrCl(cod)(DMSO)] (5, COD = cyclooctadiene) was generated from [Ir2Cl2(cod) 2]. Substitution reactions of these neutral systems afforded the complexes [RhCl(py)(DMSO)2] (6), [IrCl(py)(DMSO)2] (7), [IrCl(iPr3P)(DMSO)2] (8), [RhCl(dmbpy)(DMSO)] (9, dmbpy = 4,4′-dimethyl-2,2′-bipyridine), and [IrCl(dmbpy)(DMSO)] (10). The cationic O-bound complex [Rh(cod)(DMSO)2]BF4 (11) was synthesized from [Rh(cod)2]BF4. Treatment of the cationic complexes [M(coe)2(O=CMe2)2]PF6 (M = Rh, Ir) with DMSO gave the mixed S- and O-bound DMSO complexes [M(DMSO) 2(DMSO)2]PF6 (Rh = 12; Ir=in situ characterization). Substitution of the O-bound DMSO ligands with dmbpy or pyridine resulted in the isolation of [Rh(dmbpy)DMSO2]PF6 (13) and [Ir(py)2(DMSO)2]PF6 (14). Oxidative addition of hydrogen to [IrCl(DMSO)3] (2) gave the kinetic product fac-[Ir(H)2Cl(DMSO)3] (15) which was then easily converted to the more thermodynamically stable product mer-[Ir(H) 2Cl(DMSO)3] (16). Oxidative addition of water to both neutral and cationic IrI DMSO complexes gave the corresponding hydrido-hydroxo addition products syn-[(DMSO)2HIr(μ-OH) 2(μ-Cl)IrH(DMSO)2] [IrCl2(DMSO) 2] (17) and anti-[(DMSO)2(DMSO)HIr(μ-OH) 2IrH(DMSO)2(DMSO)][PF6]2 (18). The cationic [Ir(DMSO)2(DMSO)2(DMSO)2]PF 6 complex (formed in situ from [Ir(coe)2(O=CMe 2)2]PF6) also reacts with methanol to give the hydrido-alkoxo complex syn-[(DMSO)2HIr(μ-OCH3) 3IrH(DMSO)2]2]PF6 (19). Complexes 1, 2, 4, 5, 11, 12, 14, 17, 18, and 19 were characterized by crystallography.

Original languageEnglish
Pages (from-to)5237-5249
Number of pages13
JournalChemistry - A European Journal
Volume9
Issue number21
DOIs
Publication statusPublished - Nov 7 2003

Keywords

  • Iridium
  • O ligands
  • Oxidative addition
  • Rhodium
  • S ligands

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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