Onset temperatures of 3a–c^a.

Compd.	Onset temp. Ar [°C]	Onset temp. O2 [°C]
3a	152	166
3b	253	243
3c	120	233

^aAr, O₂ (gas flow 20 mL min⁻¹) (Ar carrier gas flow 40 mL min⁻¹, heating rate 10 °C min⁻¹).