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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1n⋯O1	0.88 (1)	2.03 (3)	2.741 (3)	138 (3)
N2—H2n⋯O2	0.88 (1)	2.01 (3)	2.726 (3)	138 (3)
N3—H3n⋯O3	0.88 (1)	1.93 (3)	2.668 (3)	140 (3)
N4—H4n⋯O4	0.87 (1)	1.96 (3)	2.677 (3)	139 (3)