The Bond N-Cl. (III): A 35Cl NQR and X-Ray Diffraction Study of N-Chloro-N-(2,6-Dichlorophenyl)-Acetamides

Abstract

(2) The crystal structures at room temperature of the N-chloro-N-(2,6-dichlorophenyl)-chloroacetamides 2,6-Cl2C-H3 NClCOCCl3 (1) and 2,6-Cl2C6H3NClCOCH2Cl have been determined. (1): orthorhombic, Pbca. Z = 8, a = 2051.7(8) pm, b = 1134.8(4) pm, c = 1089.0(4) pm. (2): orthorhombic, Pbca, Z = S, a = 2078.7 (4) pm, b= 1487.9(4) pm, c = 694.0 (2) pm. The 35Cl NQR spectrum of (1) was studied in the range 77≤T/K≤370. At 77 K, a sextet spectrum is observed (ν in MHz): v1 = ν (Cl(N) = 56.327; ν2 = 40.636, ν3 = 40.317, ν4 = 40.294; ν5 = 36.532, ν6 = 36.182. The lines ν2, ν3, and ν4 are assigned to the CCl3 group because of their position in the frequency scale. Also, due to librational motions, this triplet part of the spectrum fades out at Tf ≈ 320 K. There is no problem in assigning in both compounds, on the basis of the known 35Cl NQR frequency scale, the line ν1 to the CI atom attached to the nitrogen atom and the lines ν5 and ν6 to the ring chlorines (Cl(2) and Cl(6)). The crystal structures and NQR spectra of (1) and (2) are discussed together with literature data for 2,6-Cl2C6H3NHCOR, C6H5NClCOR (where R = CCl3, CClH2) and other substituted acetamides.