Heterodinuclear Cu(II)Zn(II) complexes: 19F NMR as a versatile tool to control the synthesis

The dinucleating ligands 2,6-bis[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenol (H-BPMP) and 2,6-bis[(bis(2-pyridylmethyl)amino)methyl]-4-fluorophenol (H-BPFP) were used to synthesize heterodinuclear (μ-phenoxo)(μ-hydroxo) Cu(II)Zn(II) complexes. The labeled ligand with a fluorine atom allows the use of 19F NMR spectroscopy, which turned to be a rapid and powerful tool to tune the synthesis of the heterodinuclear paramagnetic complex [CuZnBPFP(μOH)](ClO4)2 and avoid mixing of complexes with statistical distribution. When applied to the non-fluorinated ligand, this experimental procedure leads to prepare and isolate easily the complex [CuZnBPMP(μOH)](ClO4)2. The X-ray structure is described.