Two derivatives of 1,5-disubstituted tetrazoles: 1-(4-nitrophenyl)-1H-tetrazol-5-amine and {(E)-[1-(4-ethoxyphenyl)-1H-tetrazol-5-yl]iminomethyl}dimethylamine.

The geometric features of 1-(4-nitrophenyl)-1H-tetrazol-5-amine, C(7)H(6)N(6)O(2), correspond to the presence of the essential interaction of the 5-amino group lone pair with the pi system of the tetrazole ring. Intermolecular N-H...N and N-H...O hydrogen bonds result in the formation of infinite chains running along the [110] direction and involve centrosymmetric ring structures with motifs R(2)(2)(8) and R(2)(2)(20). Molecules of {(E)-[1-(4-ethoxyphenyl)-1H-tetrazol-5-yl]iminomethyl}dimethylamine, C(12)H(16)N(6)O, are essentially flattened, which facilitates the formation of a conjugated system spanning the whole molecule. Conjugation in the azomethine N=C-N fragment results in practically the same length for the formal double and single bonds.