Crystal structure of a G-1 dendrimer of aminoisophtalic acid

The G-1 dendrimer 4,4',4'',4'''-methanetetrayltetrakis(N-(3,5-dicarboxy-phenyl)benzamide) has been obtained from 4,4',4'',4'''-methanetetrayltetrabenzoic acid and isophtalic acid. The compound was recrystallized from methanol and its structure resolved. The crystal belongs to the tetragonal crystal system space group I-4 2d, the cell lengths being a=18.9585(16) Å, b= 18.9585(16) Å and c=23.703(2) Å. The crystal structure evidences the formation of cavities. Only one type of hydrogen bond is observed implying the nitrogen atom (acting as donor) and the oxygen atom of one carboxy group of the aminoisophtalic residue (as acceptor), while the other carboxy group does not participate in the network. The donor-acceptor distance is 3.024(2) Å.