Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N4H4NN2	0.88(2)	2.19(2)	2.6116(16)	109(1)
N1H1NO1W i	0.88(1)	2.12(1)	2.9940(15)	170(2)
N4H4NO1W	0.88(2)	2.50(2)	3.3100(15)	154(1)
O1WH1WN3	0.84(2)	2.11(2)	2.9371(16)	172(2)
O1WH2WS1ii	0.85(2)	2.50(2)	3.3412(11)	173(2)

Symmetry codes: (i) ; (ii) .