Effect of Substitution on the Molecular Geometry of N-(2/3/4-Substituted-phenyl)-2,2-dichloro-acetamides, 2/3/4-XC6H4NH-CO-CHCl2 (X = CH3 or Cl)

Abstract

2MPDCA The effect of ring substitution on the molecular geometry of amides of the type 2/3/4-XC6H4NHCO- CHCl2 (X = CH3 or Cl) has been studied by determining the crystal structures of the compounds N-(2-methylphenyl)-2,2-dichloro-acetamide, 2-CH3C6H4NH-CO-CHCl2 (); N-(3-methylphenyl)- 2,2-dichloro-acetamide, 3-CH3C6H4NH-CO-CHCl2 (3MPDCA) and N-(3-chlorophenyl)- 2,2-dichloro-acetamide, 3-ClC6H4NH-CO-CHCl2 (3CPDCA). The results are analyzed along with our earlier crystal structures of the amides N-(phenyl)-2,2-dichloro-acetamide, C6H5NH-COCHCl2 (PDCA); N-chloro-N-(phenyl)-2,2-dichloro-acetamide, C6H5NCl-CO-CHCl2 (NCPDCA); N-(4-methylphenyl)-2,2-dichloro-acetamide, 4-CH3C6H4NH-CO-CHCl2 (4MPDCA); N-(2-chlorophenyl)- 2,2-dichloro-acetamide, 2-ClC6H4NH-CO-CHCl2 (2CPDCA); N-(4-chlorophenyl)-2,2-dichloro- acetamide, 4-ClC6H4NH-CO-CHCl2 (4CPDCA). The results have also been compared and correlated with the crystal structure data of trichloro-acetamide analogues of the type 2/3/4- XC6H4NH-CO-CCl3 (X = CH3 or Cl): N-(phenyl)-2,2,2-trichloro-acetamide, N-(2-methylphenyl)- 2,2,2-trichloro-acetamide, N-(3-methylphenyl)-2,2,2-trichloro-acetamide, N-(4-methylphenyl)- 2,2,2-trichloro-acetamide, N-(2-chlorophenyl)-2,2,2-trichloro-acetamide, N-(3-chlorophenyl)-2,2,2- trichloro-acetamide, N-(4-chlorophenyl)-2,2,2-trichloro-acetamide, N-chloro-N-(phenyl)-2,2,2-trichloro- acetamide and N-(phenyl)-acetamide. The crystal system, space group, formula units and lattice constants in Å of the new structures are: 2MPDCA: monoclinic, P21/n, Z = 4, a = 4.7059(5), b = 11.600(1), c = 18.918(2), β = 94.702(9)° ; 3MPDCA: orthorhombic, P212121, Z = 4, a = 4.759(1), b = 10.543(3), c = 20.205(5); 3CPDCA: orthorhombic, Pnma, Z = 4, a = 9.935(1), b = 6.997(1), c = 14.140(2). 2MPDCA, 3MPDCA and 3CPDCA show a molecule each in their asymmetric units, in agreement with the observed 35Cl NQR spectra of the compounds