The structures of the Meisenheimer-like complexes, produced by the reaction of some mononitrobenzene derivatives with alkoxide ion, were studied by measuring the IR and NMR spectra. The complexes were formed as red crystals by mixing o- or p-nitroanilines in dichloromethane with alkoxide ion in alcohol, but they decomposed rapidly as the solvent disappeared.
From studies on spectra, some informations about the structure were obtained.
(1)For Meisenheimer-1ike c, mplexes, IR absorpti, n bands due to C shifted t, 1, w wave number side and the broad band become cramped with decreasing NOs groups.
(2) The more unstable the complexes, the stronger is the intensity of stretching vibration bands due to NO2 groups and it vanished as the complexes became stable.
(3) The ring protons of Meisenheimer-like complexes shifted to high magnetic field side, NH2 sigRals to low field and OCHs signals to high field.
It was f, und that the str, ng and broad band characteristic, f keta1-1ike structure C, appeared at 1020, -vlO40 cm-i. Ring protons in Meisenheimer-like complexes appeared at T.=2.08and Tp=3.44. On the basis of facts, it could be strongly sugguested that the structures of the complexes were