A thermal molecular migration in the solid state. Structures of isomeric 5-amino-4-(2,6-dichlorophenyl)-1-(2-nitrophenyl)-1H-1,2,3-triazole (yellow form I) and 4-(2,6-dichlorophenyl)-5-(2-nitroanilino)-2H-1,2,3-triazole (red form II), C₁₄H₉Cl₂N₅O₂

Abstract

Yellow form (I): M_r= 350.09, monoclinic, P2₁/n, Z=4, a=9.525 (1), b=14.762 (1), c= 11.268 (1) Å, β=107.82 (1)° , V=1508.3 ų, D_m(flotation in aqueous KI)=1.539 (2), D_x=1.541 (2) g cm^-3, μ (Cu Kα, λ=1.5418 Å)=40.58 cm^-1, F(000)=712, T=293 K, R=8.8% for 2054 significant refections. Red form (II): M_r=350.09, triclinic, P1, Z=2, a=9.796 (2), b= 10.750 (2), c=7.421 (1) Å, α=95.29 (2), β=70.18 (1), γ=92.76 (2)°, V=731.9 ų, D_m(flotation in KI) =1.585 (3), D_x=1.588 (3) g cm^-3, μ (Cu Kα, λ= .5418Å)=40.58 cm^-1, F(000)=356, T=293 K, R=5.8% for 1866 significant reflections. There are no unusual bond distances or angles. The triazole and two phenyl rings are planar. On the basis of packing considerations the possibility of intermolecular interactions playing a role in the reactivity of the starting material is ruled out.