Syntheses and crystal structure of 4-[(pyridin-3-yl)diazenyl]morpholine and 1-[(pyridin-3-yl)diazenyl]-1,2,3,4-tetrahydroquinoline

Two new heterocyclic 1,2,3-triazenes were synthesized by diazotation of 3-aminopyridine following respectively by coupling with morpholine or 1,2,3,4-tetrahydroquinoline. 4-[(Pyridin-3-yl)diazenyl]morpholine (I), C9H12N4O, has monoclinic P21/c symmetry at 100 K, while 1-[(pyridin-3-yl)diazenyl]-1,2,3,4-tetrahydroquinoline (II), C14H14N4, has monoclinic P21/n symmetry at 100 K. These 1,2,3-triazene derivatives were synthesized by the organic medium method by coupling reactions of 3-aminopyridine with morpholine and 1,2,3,4-tetrahydroquinoline, respectively, and characterized by 1H NMR, 13C NMR, IR, mass spectrometry, and single-crystal X-ray diffraction. The molecule of compound I consists of pyridine and morpholine rings connected by an azo moiety (–N=N–). In the molecule of II, the pyridine ring and the 1,2,3,4-tetrahydroquinoline unit are also connected by an azo moiety. The double- and single-bond distances in the triazene chain are comparable for the two compounds. In both crystal structures, the molecules are connected by C—H...N interactions, forming infinite chains for I and layers parallel to the bc plane for II.