Synthesis and characterization of novel ferrocene-containing pyridylamine ligands and their ruthenium(II) complexes: Electronic communication through hydrogen-bonded amide linkage

Takahiko Kojima, Daisuke Noguchi, Tomoko Nakayama, Yuji Inagaki, Yoshihito Shiota, Kazunari Yoshizawa, Kei Ohkubo, Shunichi Fukuzumi

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Tris(2-pyridylmethyl)amine (TPA) derivatives with one or two ferrocenoylamide moieties at the 6-position of one or two pyridine rings of TPA were synthesized. The compounds, N-(6-ferrocenoylamide-2-pyridylmethyl)-N,N- bis(2-pyridylmethyl)amine (Fc-TPA; L1) and N,N-bis(6-ferrocenoylamide-2- pyridylmethyl)-N-(2-pyridylmethyl)amine (Fc2-TPA; L2), were characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. Their Ru(II) complexes were also prepared and characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. [RuCl(L1)(DMSO)]PF6 (1) that contains S-bound dimethyl sulfoxide (DMSO) as a ligand and an uncoordinated ferrocenoylamide moiety exhibited two redox waves at 0.23 and 0.77 V (vs ferrocene/ferrocenium ion as 0 V), due to Fc/Fc+ and Ru(II)/Ru(III) redox couples, respectively. [RuCl(L2)]PF6 (2) that contains both coordinated and uncoordinated amide moieties showed two redox waves that were observed at 0.27 V (two electrons) and 0.46 V (one electron), assignable to Ru(II)/Ru(III) redox couples overlapped with the uncoordinated Fc/Fc+ redox couple and the coordinated Fc/Fc+, respectively. In contrast to 2, an acetonitrile complex, [Ru(L2)(CH3CN)](PF6)2 (3), exhibited three redox couples at 0.26 and 0.37 V for two kinds of Fc/Fc+ couples, and 0.83 V for the Ru(II)/Ru(III) couple (vs ferrocene/ferrocenium ion as 0 V). In this complex, the redox potentials of the coordinated and the uncoordinated Fc-amide moieties were discriminated in the range of 0.11 V. Chemical two-electron oxidation of 1 gave [RuIIICl(L1 +)(DMSO)]3+ to generate a ferromagnetically coupled triplet state (S = 1) with J = 13.7 cm-1 (H = -JS1S 2) which was estimated by its variable-temperature electron spin resonance (ESR) spectra in CH3CN. The electron spins at the Ru(III) center and the Fe(III) center are ferromagnetically coupled via an amide linkage. In the case of 2, its two-electron oxidation gave the same ESR spectrum, which indicates formation of a similar triplet state. Such electronic communication may occur via the amide linkage forming the intramolecular hydrogen bonding.

Original languageEnglish
Pages (from-to)886-895
Number of pages10
JournalInorganic chemistry
Volume47
Issue number3
DOIs
Publication statusPublished - Feb 4 2008

Fingerprint

Ruthenium
Amides
linkages
amides
ruthenium
Hydrogen
communication
Ligands
ligands
Communication
hydrogen
synthesis
electronics
Dimethyl Sulfoxide
Electrons
amines
X ray crystallography
atomic energy levels
Cyclic voltammetry
crystallography

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Synthesis and characterization of novel ferrocene-containing pyridylamine ligands and their ruthenium(II) complexes : Electronic communication through hydrogen-bonded amide linkage. / Kojima, Takahiko; Noguchi, Daisuke; Nakayama, Tomoko; Inagaki, Yuji; Shiota, Yoshihito; Yoshizawa, Kazunari; Ohkubo, Kei; Fukuzumi, Shunichi.

In: Inorganic chemistry, Vol. 47, No. 3, 04.02.2008, p. 886-895.

Research output: Contribution to journalArticle

@article{68b27ad9e95444f0881c3306a4caefc5,
title = "Synthesis and characterization of novel ferrocene-containing pyridylamine ligands and their ruthenium(II) complexes: Electronic communication through hydrogen-bonded amide linkage",
abstract = "Tris(2-pyridylmethyl)amine (TPA) derivatives with one or two ferrocenoylamide moieties at the 6-position of one or two pyridine rings of TPA were synthesized. The compounds, N-(6-ferrocenoylamide-2-pyridylmethyl)-N,N- bis(2-pyridylmethyl)amine (Fc-TPA; L1) and N,N-bis(6-ferrocenoylamide-2- pyridylmethyl)-N-(2-pyridylmethyl)amine (Fc2-TPA; L2), were characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. Their Ru(II) complexes were also prepared and characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. [RuCl(L1)(DMSO)]PF6 (1) that contains S-bound dimethyl sulfoxide (DMSO) as a ligand and an uncoordinated ferrocenoylamide moiety exhibited two redox waves at 0.23 and 0.77 V (vs ferrocene/ferrocenium ion as 0 V), due to Fc/Fc+ and Ru(II)/Ru(III) redox couples, respectively. [RuCl(L2)]PF6 (2) that contains both coordinated and uncoordinated amide moieties showed two redox waves that were observed at 0.27 V (two electrons) and 0.46 V (one electron), assignable to Ru(II)/Ru(III) redox couples overlapped with the uncoordinated Fc/Fc+ redox couple and the coordinated Fc/Fc+, respectively. In contrast to 2, an acetonitrile complex, [Ru(L2)(CH3CN)](PF6)2 (3), exhibited three redox couples at 0.26 and 0.37 V for two kinds of Fc/Fc+ couples, and 0.83 V for the Ru(II)/Ru(III) couple (vs ferrocene/ferrocenium ion as 0 V). In this complex, the redox potentials of the coordinated and the uncoordinated Fc-amide moieties were discriminated in the range of 0.11 V. Chemical two-electron oxidation of 1 gave [RuIIICl(L1 +)(DMSO)]3+ to generate a ferromagnetically coupled triplet state (S = 1) with J = 13.7 cm-1 (H = -JS1S 2) which was estimated by its variable-temperature electron spin resonance (ESR) spectra in CH3CN. The electron spins at the Ru(III) center and the Fe(III) center are ferromagnetically coupled via an amide linkage. In the case of 2, its two-electron oxidation gave the same ESR spectrum, which indicates formation of a similar triplet state. Such electronic communication may occur via the amide linkage forming the intramolecular hydrogen bonding.",
author = "Takahiko Kojima and Daisuke Noguchi and Tomoko Nakayama and Yuji Inagaki and Yoshihito Shiota and Kazunari Yoshizawa and Kei Ohkubo and Shunichi Fukuzumi",
year = "2008",
month = "2",
day = "4",
doi = "10.1021/ic7016038",
language = "English",
volume = "47",
pages = "886--895",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "3",

}

TY - JOUR

T1 - Synthesis and characterization of novel ferrocene-containing pyridylamine ligands and their ruthenium(II) complexes

T2 - Electronic communication through hydrogen-bonded amide linkage

AU - Kojima, Takahiko

AU - Noguchi, Daisuke

AU - Nakayama, Tomoko

AU - Inagaki, Yuji

AU - Shiota, Yoshihito

AU - Yoshizawa, Kazunari

AU - Ohkubo, Kei

AU - Fukuzumi, Shunichi

PY - 2008/2/4

Y1 - 2008/2/4

N2 - Tris(2-pyridylmethyl)amine (TPA) derivatives with one or two ferrocenoylamide moieties at the 6-position of one or two pyridine rings of TPA were synthesized. The compounds, N-(6-ferrocenoylamide-2-pyridylmethyl)-N,N- bis(2-pyridylmethyl)amine (Fc-TPA; L1) and N,N-bis(6-ferrocenoylamide-2- pyridylmethyl)-N-(2-pyridylmethyl)amine (Fc2-TPA; L2), were characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. Their Ru(II) complexes were also prepared and characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. [RuCl(L1)(DMSO)]PF6 (1) that contains S-bound dimethyl sulfoxide (DMSO) as a ligand and an uncoordinated ferrocenoylamide moiety exhibited two redox waves at 0.23 and 0.77 V (vs ferrocene/ferrocenium ion as 0 V), due to Fc/Fc+ and Ru(II)/Ru(III) redox couples, respectively. [RuCl(L2)]PF6 (2) that contains both coordinated and uncoordinated amide moieties showed two redox waves that were observed at 0.27 V (two electrons) and 0.46 V (one electron), assignable to Ru(II)/Ru(III) redox couples overlapped with the uncoordinated Fc/Fc+ redox couple and the coordinated Fc/Fc+, respectively. In contrast to 2, an acetonitrile complex, [Ru(L2)(CH3CN)](PF6)2 (3), exhibited three redox couples at 0.26 and 0.37 V for two kinds of Fc/Fc+ couples, and 0.83 V for the Ru(II)/Ru(III) couple (vs ferrocene/ferrocenium ion as 0 V). In this complex, the redox potentials of the coordinated and the uncoordinated Fc-amide moieties were discriminated in the range of 0.11 V. Chemical two-electron oxidation of 1 gave [RuIIICl(L1 +)(DMSO)]3+ to generate a ferromagnetically coupled triplet state (S = 1) with J = 13.7 cm-1 (H = -JS1S 2) which was estimated by its variable-temperature electron spin resonance (ESR) spectra in CH3CN. The electron spins at the Ru(III) center and the Fe(III) center are ferromagnetically coupled via an amide linkage. In the case of 2, its two-electron oxidation gave the same ESR spectrum, which indicates formation of a similar triplet state. Such electronic communication may occur via the amide linkage forming the intramolecular hydrogen bonding.

AB - Tris(2-pyridylmethyl)amine (TPA) derivatives with one or two ferrocenoylamide moieties at the 6-position of one or two pyridine rings of TPA were synthesized. The compounds, N-(6-ferrocenoylamide-2-pyridylmethyl)-N,N- bis(2-pyridylmethyl)amine (Fc-TPA; L1) and N,N-bis(6-ferrocenoylamide-2- pyridylmethyl)-N-(2-pyridylmethyl)amine (Fc2-TPA; L2), were characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. Their Ru(II) complexes were also prepared and characterized by spectroscopic methods, cyclic voltammetry, and X-ray crystallography. [RuCl(L1)(DMSO)]PF6 (1) that contains S-bound dimethyl sulfoxide (DMSO) as a ligand and an uncoordinated ferrocenoylamide moiety exhibited two redox waves at 0.23 and 0.77 V (vs ferrocene/ferrocenium ion as 0 V), due to Fc/Fc+ and Ru(II)/Ru(III) redox couples, respectively. [RuCl(L2)]PF6 (2) that contains both coordinated and uncoordinated amide moieties showed two redox waves that were observed at 0.27 V (two electrons) and 0.46 V (one electron), assignable to Ru(II)/Ru(III) redox couples overlapped with the uncoordinated Fc/Fc+ redox couple and the coordinated Fc/Fc+, respectively. In contrast to 2, an acetonitrile complex, [Ru(L2)(CH3CN)](PF6)2 (3), exhibited three redox couples at 0.26 and 0.37 V for two kinds of Fc/Fc+ couples, and 0.83 V for the Ru(II)/Ru(III) couple (vs ferrocene/ferrocenium ion as 0 V). In this complex, the redox potentials of the coordinated and the uncoordinated Fc-amide moieties were discriminated in the range of 0.11 V. Chemical two-electron oxidation of 1 gave [RuIIICl(L1 +)(DMSO)]3+ to generate a ferromagnetically coupled triplet state (S = 1) with J = 13.7 cm-1 (H = -JS1S 2) which was estimated by its variable-temperature electron spin resonance (ESR) spectra in CH3CN. The electron spins at the Ru(III) center and the Fe(III) center are ferromagnetically coupled via an amide linkage. In the case of 2, its two-electron oxidation gave the same ESR spectrum, which indicates formation of a similar triplet state. Such electronic communication may occur via the amide linkage forming the intramolecular hydrogen bonding.

UR - http://www.scopus.com/inward/record.url?scp=39749091147&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=39749091147&partnerID=8YFLogxK

U2 - 10.1021/ic7016038

DO - 10.1021/ic7016038

M3 - Article

C2 - 18181616

AN - SCOPUS:39749091147

VL - 47

SP - 886

EP - 895

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 3

ER -