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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O2i	0.86 (1)	1.78 (1)	2.633 (2)	175 (3)
N2—H2⋯O1ii	0.86 (1)	1.93 (1)	2.789 (2)	173 (2)
N4—H4⋯O2iii	0.87 (1)	2.24 (1)	3.077 (3)	163 (2)

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