According to research conducted in our research group on the pyridinedicarboxylate family due to their various applications in the fields of pharmaceuticals, non-linear optics, magnetism, electrical conductivity, catalyticactivity,etc, we decided tooxygenate nitrogen of pyridine ring of pyridine-2,5-dicarboxylic acid as N-oxide to investigate synthesis, coordination modes, and structure types of these compounds in view of crystal engineering concepts. In this work we report the synthesis of two novel coordination complexes with CrIII and one coordination complex based on the proton transfer mechanism with three heterocyclic bases such as 1,10-phenanthroline (phen), 2-aminopyrimidine (2-apym), and isonicotinamide (Ina). The ligands and complexes were characterized by physico-chemical approaches including elemental analysis (CHN), solid infrared (IR), mass spectrometry and conductometry techniques. Based on the conductivity analysis, high conductivity indicated the ionic nature of compounds, while low conductivity indicated molecular compounds. According to observed chemical shifts of related bands of carboxylate and N-O functional groups one can confirm that these groups are coordinated to chrome metal for two compounds.

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