Hydrogen bonded structures in organic amine oxalates

Abstract

Oxalates of n-propylamine, n-butylamine, ethylenediamine, 1,4-butanediamine, piperazine, guanidine and 1,4-diazabicyclo[2,2,2]octane (DABCO) have been synthesized and characterized by single crystal X-ray diffraction and other techniques. The amine oxalates show different types of hydrogen bonded networks, linear hydrogen bonded chains characterizing the oxalates of the first five amines. Guanidinium oxalate has a sheet like structure while DABCO oxalate has dimeric hydrogen bonded rings. Hydrogen bonded structures of these oxalates are discussed in detail, besides relating their thermal stability to the strengths of the networks.