Synthesis and structural characterization of cobalt(III) complexes of hybrid donor-type didentate or tetradentate ligands bearing dimethylphosphino and thioether groups

Kazuo Kashiwabara, Norihiko Taguchi, Hideo D. Takagi, Kiyohiko Nakajima, Takayoshi Suzuki

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13 Citations (Scopus)


The preparation and characterization of new hybrid donor-type phosphine-thioether ligands, a linear tetradentate Me2P(CH2)2S(CH2) 3S(CH2)2PMe2 (dmdtn) and a didentate Me2P(CH2)2SR [R = Me (mtdmp) or Et (etdmp)], and their cobalt(III) complexes are described. The reaction of trans-[CoCl2(py)4]Cl (py = pyridine) with dmdtn, followed by anion metathesis with NaPF6, afforded green crystals of trans(Cl,Cl)-[CoCl2{weio(S)-dmdtn}]PF6 (1), whose geometrical structure and configuration around S atoms were determined by X-ray analysis. Further reaction of 1 with Li(acac) (acac = pentane-2,4-dionate) and crystallization with LiBF4 gave red crystals of the acac complex 2. The X-ray analysis of 2 confirmed the structure and configuration of cisβ-[Co(acac) {racemic(S)-dmdtn}](BF4)2, indicating the configurational inversion at one sulfur during the derivation of complex 2. An analogous N.N-dimethyldithiocarbamate (dtc) complex 3 was also prepared, and the electrochemical properties of complexes 1-3 were discussed. For analogous mtdmp and etdmp (P-S) complexes, (rans(Cl,Cl)cis(P,P)-[CoCl2(P-S)2]PF6 reacted with Li(acac) to give not only trans(P,S)-[Co(acac)(P-S)2](PF6)2 but also [Co(acac)2(P-S)]PF6. Similar reactions with Na(dtc) yielded cis-[Co(dtc)2(P-S-κP)2] (14 for P-S = mtdmp), together with trans(P,S)-[Co(dtc)(P-S)2](PF6)2 and [Co(dtc)2(P-S)]PF6. The structures of these complexes were characterized by NMR and UV-visible spectroscopy and X-ray analysis of 14. These results suggested that the didentate ligands were hemilabile as similar to previously described SPPS-type tetradentate ligands, but the tetradentate dmdtn ligand was not.

Original languageEnglish
Pages (from-to)1817-1829
Number of pages13
Issue number11-12
Publication statusPublished - Jan 1 1998
Externally publishedYes



  • Cobalt(III)
  • Dimethylphosphino group
  • Hemilabile
  • Hybrid donor-type ligand
  • Tetradentate ligand
  • Thioether

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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