Iogansen, A. V. published the artcileThe effect of conjugation on the infrared spectra of nitro compounds, Quality Control of 1821-27-8, the publication is Doklady Akademii Nauk SSSR (1963), 153(6), 1367-9, database is CAplus.
Tabulated for RNO2 (R = Me, cyclohexyl, 1-cyclohexenyl, 1-naphthyl), p-RC6H4NO2 (I, R = H, Cl, Me, I, OH, NH2, NMe2, NEt2), o-dinitrobenzene, and 4,4′-dinitrodiphenylamine are the integrated intensities (A) of the sym. and asym. bands at 1300-1400 and 1500-1600 cm.-1, resp. With increasing conjugation, Asym. increased greatly, becoming the strongest band in the spectra, while Aasym. remained constant Addnl. values of Asym. were calculated from the intensities of Raman bands for I (R = tert-Bu, vinyl, Ph, 1,3-butadien-1-yl, ¦Â-styryl, and ¦Á-phenyl-¦Â-styryl). The length of the conjugated system as projected on the C-N plane is proportional to (Asym.)1/2. Differentiation of conjugated and nonconjugated nitro compounds is greatly facilitated.
Doklady Akademii Nauk SSSR published new progress about 1821-27-8. 1821-27-8 belongs to catalysis-chemistry, auxiliary class Nitro Compound,Amine,Benzene, name is Bis(4-nitrophenyl)amine, and the molecular formula is C12H9N3O4, Quality Control of 1821-27-8.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia