Cocrystal Structure of the Redox-active Phenylenediamine and Quinonediimine Derivatives

The cocrystal structure of diethyl 2,5-bis{[4-(ethoxycarbonyl)phenyl]amino}terephthalate (PDA) and diethyl (3E,6E)-3,6-bis{[4-(ethoxycarbonyl)phenyl]amino}cyclohexa-1,4-diene-1,4-dicarboxylate (QDI) was determined by X-ray crystallography. The compound crystallizes in a triclinic system and was characterized thus: P-1, a = 8.6778(3)Å, b =13.0702(4)Å, c = 13.5152(4)Å, α = 79.1570(15)°, β = 71.8459(15)°, γ = 72.5962(16)°, Z = 1, V = 1382.28(7)Å3. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.078 and 0.190, respectively, for all 4179 independent reflections. In the crystal, a polymeric alternating arrangement of PDA and QDI exists through a network of π-π interactions, wherein both components adopt an anti-conformation of the π-conjugated backbones.