PSEUDOHALOGEN CHEMISTRY .14. QUANTITATIVE TREATMENT OF THE ORTHO AND OTHER SUBSTITUENT EFFECTS IN THE NMR AND IR-SPECTRA OF 2-SUBSTITUTED AND 2,4-SUBSTITUTED THIOCYANATOBENZENES

H-1 and C-13 NMR chemical shifts and IR SCN stretching frequencies for 11 ortho-substituted thiocyanatobenzenes have been measured at high d ilution in an inert solvent. Data for delta C(SCN), delta C(ring), del ta H(ring and amino) and nu SCN have been correlated with substituent effects using the polar parameter (sigma(F)), the resonance parameter (sigma(R)(0)), Reynolds' short-range, non-electronic parameters (I, O, M) or Holik's second-order resonance parameter, and, as a measure of the ortho effect, the molar refraction parameter (MR) or the steric pa rameter (E-s). Excellent correlations (r > 0.99) were obtained for dat a sets involving OMe, Me, F, Cl, Br, I and CN substituents in the orth o position. Ortho NO2 and COMe substituents show deviant behaviour as the SCN group forces each of them to adopt a non-planar conformation. (C) 1997 Elsevier Science B.V.