Conformational pseudo-polymorphs and hydrogen bonding of m-di-(pyrrole-2-carboxamide)-xylylene

Two conformational pseudo-polymorphs of m-di-(pyrrole-2-carboxamide)-xylylene, anhydrous form—crystal I and 0.5 EtOAc solvate–crystal II, were obtained and characterized by X-ray crystallography. Two hydrogen bonding motifs of pyrrolic amide, having graph-set notation R21(7) were observed. The energies of the three types of hydrogen bonding motifs that normally present in the crystal structures of pyrrolic amides were calculated by DFT.