Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal-organic frameworks

Yuta Homma; Atsushi Okazawa; Takayuki Ishida

doi:10.1016/j.tetlet.2013.04.008

Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal-organic frameworks

Yuta Homma, Atsushi Okazawa, Takayuki Ishida^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

10 Citations (Scopus)

Abstract

We synthesized pyrimidine-4,6-diyl bis(tert-butyl nitroxide) (pmbNO), and characterized as a biradical by means of ESR spectroscopy. The zero-field splitting parameters were |D|/hc = 2.52 × 10^-2 cm^-1 and |E|/hc = 2.34 × 10^-3 cm^-1 in frozen toluene at 100 K. Magnetic study clarified the presence of intramolecular ferromagnetic coupling with 2J/k_B = +18.5(5) K in frozen toluene-ethanol. DFT calculation supports the ground triplet state of pmbNO. The reaction of pmbNO with Cu(hfac)₂ gave [Cu₃(pmbNO)₂(hfac) ₄], and the structure was determined by X-ray crystallographic analysis. Though the ligand was reduced to be an anion radical, pmbNO is confirmed to work as a rigid bridge, and the nitroxide oxygen atoms can ligate the metal ions.

Original language	English
Pages (from-to)	3120-3123
Number of pages	4
Journal	Tetrahedron Letters
Volume	54
Issue number	24
DOIs	https://doi.org/10.1016/j.tetlet.2013.04.008
Publication status	Published - 2013 Jun 12
Externally published	Yes

Keywords

Coordination compound
ESR
Exchange coupling
High-spin molecule
Organic free radical

ASJC Scopus subject areas

Biochemistry
Drug Discovery
Organic Chemistry

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title = "Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal-organic frameworks",

abstract = "We synthesized pyrimidine-4,6-diyl bis(tert-butyl nitroxide) (pmbNO), and characterized as a biradical by means of ESR spectroscopy. The zero-field splitting parameters were |D|/hc = 2.52 × 10-2 cm-1 and |E|/hc = 2.34 × 10-3 cm-1 in frozen toluene at 100 K. Magnetic study clarified the presence of intramolecular ferromagnetic coupling with 2J/kB = +18.5(5) K in frozen toluene-ethanol. DFT calculation supports the ground triplet state of pmbNO. The reaction of pmbNO with Cu(hfac)2 gave [Cu3(pmbNO)2(hfac) 4], and the structure was determined by X-ray crystallographic analysis. Though the ligand was reduced to be an anion radical, pmbNO is confirmed to work as a rigid bridge, and the nitroxide oxygen atoms can ligate the metal ions.",

keywords = "Coordination compound, ESR, Exchange coupling, High-spin molecule, Organic free radical",

author = "Yuta Homma and Atsushi Okazawa and Takayuki Ishida",

year = "2013",

month = jun,

day = "12",

doi = "10.1016/j.tetlet.2013.04.008",

language = "English",

volume = "54",

pages = "3120--3123",

journal = "Tetrahedron Letters",

issn = "0040-4039",

publisher = "Elsevier Limited",

number = "24",

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TY - JOUR

T1 - Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal-organic frameworks

AU - Homma, Yuta

AU - Okazawa, Atsushi

AU - Ishida, Takayuki

PY - 2013/6/12

Y1 - 2013/6/12

N2 - We synthesized pyrimidine-4,6-diyl bis(tert-butyl nitroxide) (pmbNO), and characterized as a biradical by means of ESR spectroscopy. The zero-field splitting parameters were |D|/hc = 2.52 × 10-2 cm-1 and |E|/hc = 2.34 × 10-3 cm-1 in frozen toluene at 100 K. Magnetic study clarified the presence of intramolecular ferromagnetic coupling with 2J/kB = +18.5(5) K in frozen toluene-ethanol. DFT calculation supports the ground triplet state of pmbNO. The reaction of pmbNO with Cu(hfac)2 gave [Cu3(pmbNO)2(hfac) 4], and the structure was determined by X-ray crystallographic analysis. Though the ligand was reduced to be an anion radical, pmbNO is confirmed to work as a rigid bridge, and the nitroxide oxygen atoms can ligate the metal ions.

AB - We synthesized pyrimidine-4,6-diyl bis(tert-butyl nitroxide) (pmbNO), and characterized as a biradical by means of ESR spectroscopy. The zero-field splitting parameters were |D|/hc = 2.52 × 10-2 cm-1 and |E|/hc = 2.34 × 10-3 cm-1 in frozen toluene at 100 K. Magnetic study clarified the presence of intramolecular ferromagnetic coupling with 2J/kB = +18.5(5) K in frozen toluene-ethanol. DFT calculation supports the ground triplet state of pmbNO. The reaction of pmbNO with Cu(hfac)2 gave [Cu3(pmbNO)2(hfac) 4], and the structure was determined by X-ray crystallographic analysis. Though the ligand was reduced to be an anion radical, pmbNO is confirmed to work as a rigid bridge, and the nitroxide oxygen atoms can ligate the metal ions.

KW - Coordination compound

KW - ESR

KW - Exchange coupling

KW - High-spin molecule

KW - Organic free radical

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DO - 10.1016/j.tetlet.2013.04.008

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SN - 0040-4039

VL - 54

SP - 3120

EP - 3123

JO - Tetrahedron Letters

JF - Tetrahedron Letters

IS - 24

ER -

Ground triplet pyrimidine-4,6-diyl bis(tert-butyl nitroxide) as a paramagnetic building block for metal-organic frameworks

Abstract

Keywords

ASJC Scopus subject areas

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