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Synthesis, Optical Properties and Magnetic Studies of 2,6‐Bis(pyrazolylmethyl)pyridine Functionalized with Two Nitronyl Nitroxide Radicals
Author(s) -
Zoppellaro Giorgio,
Geies Ahmed,
Andersson K. Kristoffer,
Enkelmann Volker,
Baumgarten Martin
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200701053
Subject(s) - chemistry , nitroxide mediated radical polymerization , pyridine , radical , ferromagnetism , ground state , crystallography , spin polarization , polarization (electrochemistry) , stereochemistry , photochemistry , medicinal chemistry , polymer , condensed matter physics , organic chemistry , atomic physics , electron , polymerization , physics , radical polymerization , quantum mechanics
The synthesis, optical properties, spin‐polarization path and magnetic ground‐state studies of a novel nitronyl nitroxide biradical system based on the 2,6‐bis(pyrazolylmethyl)pyridine unit is reported. Besides the presence of σ conjugation and a non‐alternant pathway for spin polarization through the core as a coupling unit, the through‐bond ferromagnetic interaction between spin carriers, although weak (0.06 cm –1 < Δ E ST = 2 J / k B < 0.6 cm –1 ), is preserved. It vanishes (2 J / k B ≈ 0) upon coordination with Zn 2+ metal ions, but is restored upon Zn 2+ depletion with EDTA. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)