Coordination chemistry of iron and cobalt supported by hybrid bis(phosphino) pyrazolylborate ligands

Motivated by the unique and versatile late transition metal chem. that has been accessed using the tris(phosphino)borate ligands, a new hybrid ligand in which one of the phosphine arms has been replaced with a pyrazolyl moiety has been designed. The coordination chem. of this ligand has been explored using both iron and cobalt. Similar to the tris(phosphine) analogs, the bis(phosphino)pyrazolylborate hybrid ligands are capable of stabilizing both low valent FeI and CoI complexes as well as FeIII and CoIII terminal imides. The synthetic methodol. providing access to this ligand and its derivs. will be discussed and the differences in coordination chem. imparted by this ligand will be presented