NH stretching vibrations and conformation of bis[2-(3-substituted ureido)phenyl] disulphides

Abstract

IR spectral data in the νNH region are used to establish the conformation of bis[2-(3-substituted ureido)phenyl]disulphides in some organic solvents. The bis[2-(3-monosubstituted ureido)phenyl]disulphides are in Z/ Z conformation forming an intramolecular S⋯HN hydrogen bond and intermolecular NH⋯OC hydrogen bonded associates. The proportion of these associates increases in the order of decreasing solvent polarity (CH 2Cl 2, CHCl 3, CCl 4). It is possible that in non-polar CCl 4 solution these ureas adopt the obviously less polar Z/ E conformation. The data obtained support the conclusion that bis [2-(3-disubstituted ureido)phenyl]disulphides are in the Z form with the NH group taking part in an intramolecular S⋯HN hydrogen bond.