Synthesis, crystal structures, and characterization of copper(II) carboxylate complexes incorporating 1,10-phenanthroline and bipyridine

Abstract

A series of Cu(II) carboxylate complexes (carboxylate = 2-fluorobenzoic acid (2-HFBA) or 4-fluorobenzoic acid (4-HFBA)) containing either one chelating 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and thermal analyses. In [Cu(bipy)(H₂O)(2-FBA)₂] (1), [Cu(bipy)(H₂O)(4-FBA)₂] (3), and [Cu(phen)(H₂O)(2-FBA)₂] (4), Cu is five-coordinate in a square pyramidal geometry and four-coordinate in [Cu(phen)(2-FBA)₂] (2). The four complexes are extended into 1-D chains through hydrogen-bonding and π ··· π interactions in 1 and 4, only hydrogen-bonding in 2, and π ··· π interactions in 3. These contacts lead to aggregation and supramolecular self-assembly.

Keywords:

• 2-Fluorobenzoic acid
• 4-Fluorobenzoic acid
• Synthesis
• Hydrogen-bonding
• π ··· π Interactions

Acknowledgments

We are grateful to Jian-Li Lin for X-ray diffraction measurements.