2,2-Bis(pyridin-2-yl)-1,3-diazinane

In the title compound, C₁₄H₁₆N₄, the six-membered hexa­hydro­pyrimidine ring adopts a chair conformation. In the crystal, one of the two pyrimidine N atoms engages in N—H...N hydrogen bonding with one of the pyridine N atoms, generating a helical chain running along the c axis. The helical pitch is the length of the c axis.

N′-[(E)-2-Chloro­benzyl­idene]thio­phene-2-carbohydrazide

There are two independent mol­ecules in the asymmetric unit of the title compound, C₁₂H₉ClN₂OS, a Schiff base derived from hydrazide, in which the dihedral angles between the thio­phene and benzene rings are 3.6 (3) and 7.3 (3)°. In the crystal, the two independent mol­ecules are arranged about an approximate non-crystallographic inversion center and are connected by two N—H...O hydrogen bonds. Weak C—H...Cl contacts are also present. Conversely, there are neither significant aromatic stacking inter­actions nor contacts involving S atoms.