Syntheses and Crystal Structures of Mono- and Bis-3-pyridinyldiazo-dipyrromethane

Two azopyrrole compounds, 1 and 2, have been synthesized and characterized. The crystal of compound 1 is of triclinic, space group P1 with a = 6.5632(10), b = 7.0805(10), c = 17.436(3) A, α = 89.504(2), β = 79.460(2), γ = 84.2788(2)o, V = 792.6(2) A3, Z = 2, C18H21N5, Mr = 307.40, Dc = 1.288 g/cm, F(000) = 328 and μ(Mo Kα) = 0.080 mm-1. The crystal of compound 2 is of triclinic, space group P1 with a = 9.7324(8), b = 9.9779(8), c = 12.3817(11) A, α = 87.052(2), β = 71.766(2), γ = 70.968(2)o, V = 1077.86(16) A3, Z = 2, C23N24H8, Mr = 412.5, Dc = 1.271 g/cm, F(000) = 436 and μ(Mo Kα) = 0.081 mm-1. The molecules of compounds 1 and 2 prefer to form dimers through pairs of N–H···N hydrogen bonds between pyrrole NH groups and pyridine N atoms. In addition, in the crystal of compound 2, the dimers self-assemble into a layer structure through N–H···N hydrogen bonds between pyrrole NH groups and azo N atoms as well as C–H···N hydrogen bonds between the ethyl groups and pyridine N atoms.