Water-soluble scorpionate ligands and their reactions with molybdenum complexes. Crystal structures of lithium tris(3-isopropylpyrazol-1-yl)methanesulfonate and Mo^VOCl₃(OPPh₃)₂·Mo^VIO₂Cl₂(OPPh₃)₂

Abstract

The water soluble ligands, lithium and potassium tris(3-isopropylpyrazol-1-yl)methanesulfonate (LiTpms ^{i Pr} and KTpms ^{i Pr}) and potassium hydrotris(3-carboxyethyl-5-methylpyrazol-1-yl)borate (), have been prepared and their reactions with simple Mo-containing starting material investigated. The crystal structure of LiTpms ^{i Pr}·1.2MeOH consists of dinuclear units containing two distinctly different, four-coordinate, tetrahedral Li centers coordinated by bidentate κ² N,O-Tpms ^{i Pr−} and methanol. The ligands fail to coordinate to aqueous molybdate under neutral to acidic conditions. Reaction of with MoO₂Cl₂(OPPh₃)₂ results in reduction and formation of Mo^VOCl₃(OPPh₃)₂·Mo^VIO₂Cl₂(OPPh₃)₂. The crystal structure of this binary mixture revealed distorted octahedral molecules in crystallographically distinct sites.

Keywords:

• Scorpionate ligands
• Molybdenum complexes
• Co-crystallization
• X-ray crystal structure

Acknowledgements

We thank Ms Sally Duck (Monash University) for mass spectrometric data and gratefully acknowledge the financial support from the Australian Research Council and the Donors of the Petroleum Research Fund (administered by the American Chemical Society).