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

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 γ-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 (χm) of 1 has been fitted by the Curie–Weiss law with θ = −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⋯O–N contacts of γ-CH and tBu groups hydrogen atoms, in which the former path dominates over the latter.

View of the 3-D supramolecular network along a axis of 1 formed from four symmetrically related columns. Figure optionsDownload as PowerPoint slideHighlights
► Novel N-TEMPO-3,5-di-tert-butylsalicylaldimine nitroxyl radical has been synthesized.
► The radical compound is found to exhibit weak antiferromagnetic interactions (θ = −0.30 K) of Curie–Weiss behavior at T < 10 K.
► Crystal structure features of this radical revealed the co-existence of intermolecular intra-sheet antiferromagnetic and ferromagnetic interactions through C–H⋯O–N contacts of γ-CH and tBu groups hydrogen atoms, in which the former dominate over the latter.