A triplet biradical with double bidentate sites based on tert-butyl pyridyl nitroxide as a candidate for strong ferromagnetic couplers

We synthesised a new biradical, 34bpybNO, having two chelating radical sites and demonstrated its crystal structure and ground triplet nature. Frozen-solution magnetic measurement and electron spin resonance results revealed a strong intramolecular ferromagnetic coupling reaching 2J/kB = ∼+170 K, which is supported by density functional theory calculations