A new ester substituted heteroscorpionate ligand

The new dihydrobis(3-carboxyethyl-5-methylpyrazolyl)borate ligand BpCOOET,Me is prepared as its potassium salt in kerosene solution, using ethyl 3-methylpyrazole-5-carboxylate and KBH4, through careful temperature control. BpCOOET,Me reacts with CuCl and PPh3 to yield the {Cu(BpCOOET,Me)PPh3} complex. BpCOOET,Me and {Cu(BpCOOET,Me)PPh3} have been fully characterized by elemental analyses and FT-IR in the solid state and by NMR (1H, 13C and 31P) spectroscopy and electrospray ionization mass spectrometry in solution. A single crystal structural characterization is reported for {Cu(BpCOOET,Me)PPh3}.