New N,N,O,O functionalized heteroscorpionate ligands and related Zn(II) and Cd(II) derivatives

The new [(3-carboxy-5-methyl-1H-1-pyrazolyl) (3-methyl-5-carboxy-1H-1-pyrazolyl)methane], CH2(PzCOOH,Me)(PzMe,COOH), and bis(3-carboxy-5-methyl-1H-1-pyrazolyl)methane, CH2(PzCOOH,Me)2, ligands are prepared in CH2Cl2/H2O solution using the ethyl 3-methylpyrazole-5-carboxylate, an excess of Na2CO3, and benzyltriethylammonium chloride as the phase transfer catalyst. The CH2(PzCOOH,Me)2 ligand reacts with ZnAc2 and CdCl2 in the presence of two equivalents of NaOH, to yield the {M[CH2(PzCOOH,Me)2] · nH2O} (M=Zn(II), n=2; M=Cd(II), n=1) complexes. All compounds have been fully characterized by elemental analyses and FT-IR in the solid state and by NMR (1H, 13C, and 113Cd) spectroscopy and electrospray ionization mass spectrometry in solution. The complexes likely contain a five- or six-coordinate metal core in which the ligand is coordinated to the metal ions in the κ4-N,N′,O,O′fashion.