Structures of 3,6-dimethoxy-1,2,4,5-tetrazine(V) and 3,6-Bis(1-aziridinyl)-1,2,4,5-tetrazine(VI)

Abstract

(V): C4H6N4O2, Mr=142·12, orthorhombic, Pbca, a=6·865(3), b =13·192(5), c=7·013(3)A, V =635·1(7)A3, Z=4, Dx=1·486gcm-3, λ(MoKα)=0·71069A, μ=1·139cm-1, F(000)=296, T=295K, R=0·043 for 589 unique observed reflections [I ≥ 1·96σ(I)]. (VI): C6H8N6, Mr=164·18, monoclinic, C2/m, a=9·660(2), b=9·077(1), c=4·294(1)A, β=91·07(I)°, V=376·5(2)A3, Z=2, Dx=1·448gcm-3, λ(MoKα)=0·71069 A, μ=0·952 cm-1, F(000)=172, T=295K, R=0·037 for 405 unique observed reflections [I≥1·96σ(I)]. (V) and (VI) are centrosymmetric, with planar 1,2,4,5-tetrazine rings slightly compressed in the C···C direction (N-C-N≅126°). The remarkably short exocyclic C-O [1·328(2)A] and C-N[1·385(1)A] bond distances indicate that the methoxy and aziridinyl substituents act as π donors to the electron-deficient 1,2,4,5-tetrazine system.