The effects of halogen and solvent on the conformation and NH stretching of 1,1-dihalogeno-heptan-1amines [CH3(CH2)(5)CX2NH2: X = F, Cl or Br] were investigated using the density functional theory method. The functional used was B3LYP employing the 6-31++G(d,p) basis set for all atoms. Computations were carried out for ten possible conformational isomers of the compounds, in the gas phase and both in a non-polar solvent (benzene) and in a polar solvent (methanol). This research work indicates that both the halogen and the medium affect conformational preference, geometrical parameters and NH vibrational frequency. The findings of this work can be useful to those systems involving changes in the conformations analogous to the compounds studied. (C) 2014 Elsevier B.V. All rights reserved.