Synthesis, Spectroscopic, Crystal Structures, and Potentiometric Studies of a Proton Transfer Compound of Acridine with Pyridine-2,6-dicarboxylic Acid and a Novel Palladium(II) Complex with Coordination of Acridine

Abstract

A proton-transfer ion pair compound, (acrH)⁺(pydcH)⁻·H₂O (1), was synthesized by the reaction of acridine (acr) and pyridine-2,6-dicarboxylic acid (pydcH₂). The reaction of compound 1 with palladium (II) chloride led to palladium (II) complex formulated as [Pd(pydc)(acr)] (2). Compounds 1 and 2 were characterized by elemental analysis, ¹H NMR, IR, UV–Vis spectroscopy as well as X-ray diffraction method. Intermolecular hydrogen-bonding interactions, as well as π–π stacking, play important roles in the structure of compound 1. The equilibrium constants of acid (pydc) and acridine (acr), as well as complex, were investigated by a potentiometric pH titration method.

Keywords:

• acridine
• crystal structure
• palladium(II) complex
• potentiometric study
• pyridine-2
• 6-dicarboxylic acid
• stability constant

Acknowledgment

The authors gratefully acknowledge the support from the Islamic Azad University Khorramabad Branch and University of California, Davis.