Heteroatomic high-spin molecules are suitable for a model study of room-tem
perature stable molecular based magnetics. We studied high-spin nitrenes (S
= 1 and 2) with s-triazine skeleton, which were generated by the photolysi
s of the polyazide precursor. We identified mononitrene 1 (S = 1) and bisni
trene 2 (S = 2) for the first time by single-crystal ESR measurements. The
fine-structure parameters were determined by the angular dependence of reso
nance fields. The determined fine-structure parameters were \D\ = 1.402 cm(
-1) and \D\ = 0.280 cm(-1) for mononitrene 1 and bisnitrene 2, respectively
. The large D values indicate that pi-spin delocalization effects were hamp
ered by introducing heteroatoms to pi-spin systems. The hyperfine splitting
s due to the monovalent nitrogen nucleus of 1 were observed with magnetic f
ield along the principal axis of the fine structure tensor. The hyperfine s
plitting constant was about 0.0018 cm(-1). The temperature dependence of ES
R signals showed that 1 and 2 were triplet and quintet in the ground state,
respectively.