Synthesis, crystal structure and intermolecular magnetic interactions of a new N-TEMPO-3,5-di-tert-butylsalicylaldimine radical

Abstract

A new N-TEMPO-3,5-di-tert-butylsalicylaldimine radical (1) has been synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR, UV-vis, and EPR spectroscopy and temperature dependent magnetic susceptibility. X-ray diffraction revealed that H-atoms of gamma-CH in TEMPO and CH3 in salicylaldimine moieties, are located in close contact with the neighboring N-O radical group in crystal 1. The temperature dependence of the magnetic susceptibility (chi(m)) of 1 has been fitted by the Curie-Weiss law with theta = -0.3 K within 10-300 K, suggesting the presence of a weak intermolecular antiferromagnetic interaction between radical centers at T < 10 K. It has been demonstrated that radical 1 possesses crystal structure involving co-existence of antiferromagnetic and ferromagnetic interactions through C-H center dot center dot center dot O-N-center dot contacts of gamma-CH and 'Bu groups hydrogen atoms, in which the former path dominates over the latter. (C) 2011 Elsevier Masson SAS. All rights reserved.