Preparation, Structure, and Spectroscopy of Cobalt(III) Complexes Containing N,N-Di-8-quinolyl Derivatives of 1,2-Diaminoethane, (R)-1,2-Diaminopropane, and (R,R)-l, 2-Diaminocyclohexane

Toshishige M. Suzuki, Sigeru Ohba, Shoichi Sato, Yoshihiko Saito, Kazuo Saito, Toshishige M. Suzuki, Sigeru Ohba, Yoshihiko Saito, Shoichi Sato

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8 Citations (Scopus)

Abstract

Mixed-ligand cobalt(III) complexes have been prepared by the reaction of tris(acetylacetonato)cobalt(III) with an N,-N′-N-8-quinolyl-l,2-diaminoalkane (1,2-diaminoethane, (R)-1,2-diaminopropane, and (R,R)-1,2-diaminocyclohexane) in organic solvents. The isolated complexes have deprotonated secondary amino nitrogens. The parent complexes with neutral ligands were readily formed on addition of hydrogen chloride in organic solvents, but the crystals were isolated with difficulty. The absorption, CD, and 1H NMR spectra change rapidly and reversibly on protonation and deprotonation of the quadridentate ligand. The X-ray crystal structure analysis of [Co(acac)(R-dqpn)]ClO4, which contains the deprotonated form of dqpn (dqpn = N,N′-di-8-quinolyl-l,2-diaminopropane), has been performed in order to clarify the detailed structure. Crystal data: CoClO6N4C26H26, a = 11.112 (2) Å, b = 13.299 (5) Å, c = 9.275 (4) Å, α = 106.06 (4), β = 88.72 (3), γ = 85.87 (3), space group P1,Z = 2, R = 5.7% for 4327 observed reflections. The two independent complex cations consist of the Δ- and Λ-isomers. The stereochemistry including geometrical and optical isomerism of both the protonated and deprotonated complexes is discussed on the basis of the crystal structure and spectroscopic data in solution. The quadridentate ligands seem to undergo rapid rearrangement on protonation and deprotonation of the complexes.

Original languageEnglish
Pages (from-to)2048-2054
Number of pages7
JournalInorganic Chemistry
Volume22
Issue number14
DOIs
Publication statusPublished - 1983 Jul

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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