Creation of hydrogen bonded 1D networks by co-crystallization of N,N′-bis(2-pyridyl)aryldiamines with dicarboxylic acids

The preparation and crystal structures of fourteen complexes of N,N'-bis(2-pyridyl)aryldiamines with dicarboxylic acids and two complexes with squaric acid are reported. The recognition between the carboxylic acids and the 2-aminopyridine units occurs through the formation of the cyclic R-2(2) (8) hydrogen bond motif, whereas squaric acid creates the analogous R-2(2) (9) motif. In the 1 : 1 complexes the cyclic motifs generate infinite hydrogen-bonded 1D networks with the alternating component molecules. These networks are further organised into densely packed layers assembled through weaker C-H ... O interactions. Analysis of the intermolecular interactions in these complexes led us to the synthesis of N,N'-bis(2-pyridyl)-2,2'-oxybis(aminobenzene) (5) which acts as a tritopic receptor of the carboxylic group and forms exclusively 2 : 1 complexes with dicarboxylic acids.