Hydrogen bonding in acetylene containing dichlorodiazaalkadienes

The detailed study of 1-aryl-4,4-dichloro-3-(2-propargyloxyphenyl)-1,2-diazabuta-1,3-dienes revealed the formation of dimeric structures via hydrogen bonding between the terminal acetylene hydrogen atom and the diazo fragment of the second molecule in the solid state, in solution the compounds being monomeric. This effect is confirmed by IR spectra, X-ray data as well as quantum chemical calculations. © 202