First-row transition-metal complexes of a new pentadentate ligand, alpha,alpha,alpha',alpha'-tetra(pyrazolyl)lutidine

A new pentadentate ligand, alpha,alpha,alpha',alpha'-tetra(pyrazolyl)lutidine, pz 4lut, has been prepared by a CoCl 2-catalyzed rearrangement reaction between 2,6-pyridinedicarboxaldehyde and dipyrazolylthione. The coordination chemistry with some divalent first-row transition metal (Mn, Fe, Co, Ni, Cu, and Zn) chlorides has been explored. The electronic properties indicate that the new kappa (5)N ligand is a slightly stronger-field donor to Ni (2+) and Co (2+) than a related pentadentate ligand with five pyridyl donors presumably because of greater interaction between the metal and axial pyridyl.