Synthesis, spectroscopic and magnetic properties of lanthanide(III) complexes with a chelated imino nitroxide radical

Toshiaki Tsukuda, Takayoshi Suzuki, Sumio Kaizaki

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Abstract

The treatment of [Ln(hfac)3(H2O)2] (Ln(III)= Y, Nd-Lu) with IM-2py (2-(2-pyridyl)-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxyl) readily gave a series of novel rare earth or lanthanide radical complexes [Ln(hfac)3(IM-2py)]. The molecular structures of the Sm, Gd, Dy, Er and Yb complexes have been determined to be bicapped trigonal prismatic (TP RS) by X-ray diffraction. The magnetic susceptibility data for [Gd(hfac)3(IM-2py)] show that the Gd-IM-2py interaction is weakly antiferromagnetic with an exchange coupling constant J = -3.00 cm-1 in contrast to the ferromagnetic interaction in the Gd(III)-nitronyl nitroxide complexes. The n-π* transition of IM-2py is found to shift to lower frequency associated with intensity enhancement and vibronic structure. The luminescence measurement of the Eu(III) and Tb(III) complexes demonstrated energy transfers for IM-2py (SOMO π*) → Ln(III) (4f) as a result of emission quenching; this depends on the energy gap between the excited levels in Ln(III) and IM-2py. These results reveal that the metal-radical interactions are very weak magnetically but are relatively strong with respect to energy transfer.

Original languageEnglish
Pages (from-to)1721-1726
Number of pages6
JournalJournal of the Chemical Society, Dalton Transactions
Issue number8
Publication statusPublished - 2002
Externally publishedYes

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Lanthanoid Series Elements
Energy transfer
Magnetic properties
Exchange coupling
Magnetic susceptibility
Molecular structure
Rare earths
Luminescence
Quenching
Energy gap
Metals
X ray diffraction
nitroxyl

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

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title = "Synthesis, spectroscopic and magnetic properties of lanthanide(III) complexes with a chelated imino nitroxide radical",
abstract = "The treatment of [Ln(hfac)3(H2O)2] (Ln(III)= Y, Nd-Lu) with IM-2py (2-(2-pyridyl)-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxyl) readily gave a series of novel rare earth or lanthanide radical complexes [Ln(hfac)3(IM-2py)]. The molecular structures of the Sm, Gd, Dy, Er and Yb complexes have been determined to be bicapped trigonal prismatic (TP RS) by X-ray diffraction. The magnetic susceptibility data for [Gd(hfac)3(IM-2py)] show that the Gd-IM-2py interaction is weakly antiferromagnetic with an exchange coupling constant J = -3.00 cm-1 in contrast to the ferromagnetic interaction in the Gd(III)-nitronyl nitroxide complexes. The n-π* transition of IM-2py is found to shift to lower frequency associated with intensity enhancement and vibronic structure. The luminescence measurement of the Eu(III) and Tb(III) complexes demonstrated energy transfers for IM-2py (SOMO π*) → Ln(III) (4f) as a result of emission quenching; this depends on the energy gap between the excited levels in Ln(III) and IM-2py. These results reveal that the metal-radical interactions are very weak magnetically but are relatively strong with respect to energy transfer.",
author = "Toshiaki Tsukuda and Takayoshi Suzuki and Sumio Kaizaki",
year = "2002",
language = "English",
pages = "1721--1726",
journal = "Dalton Transactions",
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T1 - Synthesis, spectroscopic and magnetic properties of lanthanide(III) complexes with a chelated imino nitroxide radical

AU - Tsukuda, Toshiaki

AU - Suzuki, Takayoshi

AU - Kaizaki, Sumio

PY - 2002

Y1 - 2002

N2 - The treatment of [Ln(hfac)3(H2O)2] (Ln(III)= Y, Nd-Lu) with IM-2py (2-(2-pyridyl)-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxyl) readily gave a series of novel rare earth or lanthanide radical complexes [Ln(hfac)3(IM-2py)]. The molecular structures of the Sm, Gd, Dy, Er and Yb complexes have been determined to be bicapped trigonal prismatic (TP RS) by X-ray diffraction. The magnetic susceptibility data for [Gd(hfac)3(IM-2py)] show that the Gd-IM-2py interaction is weakly antiferromagnetic with an exchange coupling constant J = -3.00 cm-1 in contrast to the ferromagnetic interaction in the Gd(III)-nitronyl nitroxide complexes. The n-π* transition of IM-2py is found to shift to lower frequency associated with intensity enhancement and vibronic structure. The luminescence measurement of the Eu(III) and Tb(III) complexes demonstrated energy transfers for IM-2py (SOMO π*) → Ln(III) (4f) as a result of emission quenching; this depends on the energy gap between the excited levels in Ln(III) and IM-2py. These results reveal that the metal-radical interactions are very weak magnetically but are relatively strong with respect to energy transfer.

AB - The treatment of [Ln(hfac)3(H2O)2] (Ln(III)= Y, Nd-Lu) with IM-2py (2-(2-pyridyl)-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxyl) readily gave a series of novel rare earth or lanthanide radical complexes [Ln(hfac)3(IM-2py)]. The molecular structures of the Sm, Gd, Dy, Er and Yb complexes have been determined to be bicapped trigonal prismatic (TP RS) by X-ray diffraction. The magnetic susceptibility data for [Gd(hfac)3(IM-2py)] show that the Gd-IM-2py interaction is weakly antiferromagnetic with an exchange coupling constant J = -3.00 cm-1 in contrast to the ferromagnetic interaction in the Gd(III)-nitronyl nitroxide complexes. The n-π* transition of IM-2py is found to shift to lower frequency associated with intensity enhancement and vibronic structure. The luminescence measurement of the Eu(III) and Tb(III) complexes demonstrated energy transfers for IM-2py (SOMO π*) → Ln(III) (4f) as a result of emission quenching; this depends on the energy gap between the excited levels in Ln(III) and IM-2py. These results reveal that the metal-radical interactions are very weak magnetically but are relatively strong with respect to energy transfer.

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