Diazepines. Part 24. Crystal and molecular structure of 2,3-dihydro-5,7-dimethyl-1,4-diazepinium perchlorate

Abstract

The cation of the title compound (I) contains a five-atom delocalized 1,5-diazapentadienium chain [N(1), N(4), C(5)–(7); mean C–C 1.390, mean C–N 1.318 Å] whose ends are linked by two methylene groups in a staggered conformation. The five atoms are arranged helically, and distances of atoms from the least-squares plane through them are: N(1)–0.22, N(4) 0.21 Å, and methylene carbon atoms C(2) and C(3)–0.48 and 0.51 Å. The crystal structure contains discrete diazepinium cations and perchlorate anions linked in chains by N–H ⋯ O hydrogen bonds (2.996 and 3.176 Å). Crystals are orthorhombic, space group Pn2₁a, with Z= 4 in a unit cell of dimensions a= 9.946(2), b= 11.311(1), and c= 9.276(1)Å. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations to R 0.027 for 834 observed reflections.