Research in Scorpionate Ligands: Chiral Tris(pyrazolyl)methanes

Tris(pyrazolyl)methanes (tpms) are a versatile class of ligand consisting of a central carbon atom bonded to a nitrogen on each of three pyrazoles. By using pyrazoles derived from either menthone or camphor, chiral tpm ligands were synthesized. The synthesis included preparation of a pyrazole from either menthone or camphor followed by incorporation of either one or three of the chiral pyrazoles into a tpm ligand. The ligands were characterized through 1H NMR spectroscopy and X-ray crystallography. In some cases, complexes with Fe(II) were formed with the new ligands, which could be either high-spin (HS) or low-spin (LS), depending on the structure of the ligand.