Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2′⋯O1i	0.85 (2)	2.10 (2)	2.935 (5)	171 (4)
N4—H4′⋯O2ii	0.86 (2)	2.05 (2)	2.894 (5)	166 (4)
N6—H6′⋯O3iii	0.86 (2)	2.30 (2)	3.164 (5)	174 (4)

Symmetry codes: (i) ; (ii) ; (iii) .