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Title: Rigid Core Anthracene and Anthraquinone Linked Nitronyl and Iminoyl Nitroxide Biradicals

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1345415
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystal Growth and Design; Journal Volume: 16; Journal Issue: 7
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Akpinar, Handan, Schlueter, John A., Allão Cassaro, Rafael A., Friedman, Jonathan R., and Lahti, Paul M.. Rigid Core Anthracene and Anthraquinone Linked Nitronyl and Iminoyl Nitroxide Biradicals. United States: N. p., 2016. Web. doi:10.1021/acs.cgd.6b00588.
Akpinar, Handan, Schlueter, John A., Allão Cassaro, Rafael A., Friedman, Jonathan R., & Lahti, Paul M.. Rigid Core Anthracene and Anthraquinone Linked Nitronyl and Iminoyl Nitroxide Biradicals. United States. doi:10.1021/acs.cgd.6b00588.
Akpinar, Handan, Schlueter, John A., Allão Cassaro, Rafael A., Friedman, Jonathan R., and Lahti, Paul M.. 2016. "Rigid Core Anthracene and Anthraquinone Linked Nitronyl and Iminoyl Nitroxide Biradicals". United States. doi:10.1021/acs.cgd.6b00588.
@article{osti_1345415,
title = {Rigid Core Anthracene and Anthraquinone Linked Nitronyl and Iminoyl Nitroxide Biradicals},
author = {Akpinar, Handan and Schlueter, John A. and Allão Cassaro, Rafael A. and Friedman, Jonathan R. and Lahti, Paul M.},
abstractNote = {},
doi = {10.1021/acs.cgd.6b00588},
journal = {Crystal Growth and Design},
number = 7,
volume = 16,
place = {United States},
year = 2016,
month = 7
}
  • Calix[4]arenes constrained to 1,3-alternate conformation and functionalized at the upper rim with four and two nitronyl nitroxides have been synthesized, and characterized by X-ray crystallography, magnetic resonance (EPR and {sup 1}H NMR) spectroscopy, and magnetic studies. Such calix[4]arene tetraradicals and diradicals provide scaffolds for through-bond and through-space intramolecular exchange couplings.
  • The magnetic behavior of a series of compounds with general formula RE(hfac)[sub 3]NITEt (RE = Tb, Er, Ho; hfac = hexafluoracetylacetonate; NITEt = 2-ethyl-4,4,5,5-tetramethyl-4,5-dihydro-1 H-imidazolyl-1-oxyl 3-oxide) are reported. The presence of lanthanide ions with anisotropic ground states deeply influences the magnetic behavior of these low-dimensional systems. In particular magnetic phase transitions to ordered states are observed. The nature of these transitions is analyzed and the unusually high critical temperatures are related to the anisotropy of the rare earth metal ions. The coupling mechanisms are reconsidered in comparison with those discussed for similar systems where diamagnetic or isotropic metal ions aremore » present.« less
  • The effect of high pressure on the ferromagnetic properties of a crystalline sample of an organic radical, 2-(4-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy 3-oxide (I), has been studied with the use of a combination of a Faraday susceptometer and a Be-Cu high-pressure clamp cell. The magnetic susceptibility of I increases markedly with increasing pressure at low temperatures, and furthermore its increment increases monotonically with decreasing temperature down to about 5 K. The Weiss constant under a pressure of 9 kbar corresponds to a 40% increase in the ferromagnetic intermolecular interaction, and the magnetization at 9 kbar also comes to saturation more rapidly compared with themore » behavior under an ambient pressure. A simple calculation of the intermolecular overlap integrals between the frontier orbitals can semiquantitatively interpret the pressure-induced enhancement of the ferromagnetic coupling.« less
  • Three Radical-Ln(III)-Radical complexes based on nitronyl nitroxide radicals have been synthesized, structurally and magnetically characterized: [Gd(hfac){sub 3}(NITPhOEt){sub 2}] (1) (hfac=hexafluoroacetylacetonate, and NITPhOEt=4'-ethoxy-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), [Gd(hfac){sub 3}(NITPhOCH{sub 2}Ph){sub 2}] (2) (NITPhOCH{sub 2}Ph=4'-benzyloxy-phenyl-4,4,5, 5-tetramethylimidazoline-1-oxyl-3-oxide) and [Lu(hfac){sub 3}(NITPhOCH{sub 2}Ph){sub 2}] (3). The X-ray crystal structure analyses show that the structures of the three compounds are similar and all consist of the isolated molecules, in which central ions Gd{sup III} or Lu{sup III} are coordinated by six oxygen atoms from three hfac and two oxygen atoms from nitronyl radicals. The magnetic studies show that in both of the two Gd{sup III} complexes, there are ferromagnetic Gd{supmore » III}-Rad interactions and antiferro-magnetic Rad-Rad interactions in the molecules (with J{sub Rad-Gd}=0.27 cm{sup -1}, j{sub Rad-Rad}=-2.97 cm{sup -1} for 1: and J{sub Rad-Gd}=0.62 cm{sup -1}, j{sub Rad-Rad}=-7.01 cm{sup -1} for 2). An analogous complex of [Lu(hfac){sub 3} (NITPhOCH{sub 2}Ph){sub 2}] (3) containing diamagnetic Lu{sup III} ions has also been introduced for further demonstrating the nature of magnetic coupling between radicals. - Graphical abstract: Two tri-spin complexes based on gadolinium-radical have been synthesized and characterized, the magnetic studies show that in the two complexes the Gd-radical interaction is ferromagnetic and the radical-radical interaction is antiferromagnetic. An analogous complex containing the diamagnetic Lu{sup III} ions has also been synthesized to further demonstrate the nature of the magnetic coupling between radicals.« less
  • Five novel Ln(III) complexes based on a new nitronyl nitroxide radical have been synthesized, characterized structurally and magnetically: [Ln(hfac)₃(NITPh-3-Br-4-OMe)₂] (Ln(III)=Eu(1), Gd(2), Tb(3), Dy(4), Ho(5); hfac=hexafluoroacetylacetonate; and NITPh-3-Br-4-OMe=2-3´-Br-4´-methoxyphenyl-4,4,5,5 -tetramethylimidazoline-1-oxyl-3-oxide). The single-crystal structures analyses show that these complexes have similar mononuclear tri-spin structures, in which central Ln(III) ions are all eight coordinated by three hfac molecules and two NITPh-3-Br-4-OMe radicals. The variable-temperature magnetic susceptibility studies reveal the antiferromagnetic interactions between the paramagnetic ions (Ln(III) and radicals) in complexes 1, 2, 3 and 5 and ferromagnetic interaction in complex 4. The luminescence characterizations of complexes Eu(1), Tb(3) and Dy(4) are also studied inmore » this paper. - Graphical abstract: Using a novel halogen phenyl-substituted nitronyl-nitroxide radical, we obtained and characterized five isostructural lanthanide mononuclear tri-spin compounds. Highlights: • A new halogen phenyl-substituted nitronyl-nitroxide radical was designed. • Five new Ln(III) radical complexes have been synthesized and characterized. • The reasonable evaluation the magnetic interactions between Ln(III) ions and radical is meaningful. • These complexes show good luminescent properties.« less