Synthesis, spectroscopic investigation and X-ray structure of mononuclear and binuclear oxo complexes of rhenium(V) with pyrazolato ligands

Abstract

The [{Re(O)Cl(PPh3)}2(μ-O)(μ-N2C3H3)2] (1), [{Re(O)Br(PPh3)}2(μ-O)(μ-N2C3H3)2] (2), [ReOCl2{η2-N2C3H3CMe2O}(PPh3)] (3) and [ReOBr2{η2-N2C3H3CMe2O}(PPh3)] (4) complexes have been synthesized by reacting [ReOX3(PPh3)2] with an excess of pyrazole under different conditions. The rhenium(V) centers of (1) and (2) are linked through two bridging pyrazolato anions and an oxo group. The rhenium(V) atoms in mononuclear complexes (3) and (4) are six coordinated in an octahedral environment with a trans arrangement of the oxo group and oxygen atom of anionic bidentate ligand C3H3N2C(Me)2O− formed in the reaction of pyrazole and Me2CO.