Formation, X-ray structure and magnetic properties of two carboxy-bridged copper(II) complexes with tridentate bipyridine- and phenanthroline-based 1,3-thiazoles ligands

The synthesis and characterization using UV/Vis and emission spectroscopy, elemental analysis and EPR spectroscopy of two polynuclear copper(II) complexes (C1 and C2) with the tridentate ligands methyl 2-(2-(2,2′-bipyridin-6-yl)-5-methylthiazol-4-yloxy)acetate (1) and methyl 2-(5-methyl-2-(1,10-phenanthrolin-2-yl)thiazol-4-yloxy)acetate (2) is presented. The X-ray structures of the two complexes reveal the tridentate nature of the ligands. The copper(II) centers of C1 and C2 are linked via two carboxy-groups of the acetic acid substructure of the ligands after saponification of the methyl ester to form a dinuclear complex for C1 and a tetranuclear complex for C2. The Cu–Cu–core distances are considerably large and lie in the range of 4.27 to 7.21 Å.

Graphical abstractShown is a representation of the ligands and a simplified reaction arrow (loss of MeOH due to the saponification of the ester) leading to one of the described complexes (pictured as an ORTEP-Plot).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis and X-ray structure of polynuclear copper(II) complexes. ► Characterization using UV/Vis, emission and EPR spectroscopy. ► Fluorescent tridentate ligands with 1,3-thiazole N-donors.