Direct synthesis of heterometallic Cu/Mo complexes with aromatic chelating N,N-donating ligands

•Direct synthesis of a series of Cu/Mo heterometallic complexes.•Influence of reaction mixture temperature, components ratio and Mo-source.•Electrochemical, thermal, X- and Q-band EPR study of the compounds.

A series of novel heterometallic complexes [CuL2MoO4] xH2O [L = phen (1,10-phenanthroline) (1), 5,5′-Me2bpy (5,5′-dimethyl-2,2′-bipyridine) (3a), bpy (2,2′-bipyridine) (5), x = 2.5 (1), 3 (3) and 4.5 (5)], [Cu(5,5′-Me2bpy)2MoO4] 0.5(5,5′-Me2bpy) 8H2O (3b) [Cu(phen)2Mo2O7(phen)] 8H2O (2), and {[Cu(4,4′-Me2bpy)2]2MoO4}(OH)2 5.25H2O (4) [4,4′-Me2bpy = 4,4′-dimethyl-2,2′-bipyridine] have been synthesized by interaction of copper metal with Mo source and ligands in aqueous solutions. The complexes were characterized by elemental analysis, IR and EPR spectroscopy, TG, CV as well as single crystal X-ray diffraction analysis. X-ray crystallographic study of the compounds has shown that the complexes 1–4 possess molecular structures while 5 can be described as a molecular cation. The influence of Mo source, molecular ratio of the components and temperature of the reaction mixture on formation of particular target compounds has been investigated.

Graphical abstractA series of the Cu/Mo complexes have been obtained using direct synthesis approach. Several Mo sources were examined. The study showed a significant effect of temperature on the product nature. The EPR spectroscopy revealed that metallic copper was dissolved without reducing Mo(VI). The electrochemical study supported the oxidation states of Cu(II) and Mo(VI).Figure optionsDownload full-size imageDownload as PowerPoint slide