Structural Features of Monomeric Octahedral d2-Rhenium(V) Monooxo Complexes with Oxygen Atoms of Tridentate Chelating (O,N,S) Ligands

Resumo

The structural features of 31 mononuclear octahedral d²-Re(V) monooxo complexes with tridentate chelating (O,N,S) ligands, [ReO\(\left( {{\text{L}}_{{{\text{tri}}}}^{m}} \right)\)\(\left( {{\text{L}}_{{{\text{bi}}}}^{n}} \right)\)] and [ReO\(\left( {{\text{L}}_{{{\text{tri}}}}^{m}} \right)\)(L_mono)₂] (L_mono = Cl, Br, OMe, OPPh₃, PPh₃) are considered. The Re–O\({{\left( {{\text{L}}_{{{\text{tri}}}}^{m}} \right)}_{{trans}}}{\kern 1pt} ,\) Re–O\({{\left( {{\text{L}}_{{{\text{bi}}}}^{n}} \right)}_{{trans}}}{\kern 1pt} ,\) and Re–O(OMe) bonds in 14 complexes were found to be commensurable in length with (or shorter than) analogous cis-bonds. This indicates the presence of pseudo-dioxo ReO₂ groups in these structures with increased orders of both Re–O bonds located in trans-positions relative to each other. In the structures of 12 compounds, the Re–O(L_tri)_trans, Re–O(L_bi)_trans, and Re–O(OPPh₃) bonds are markedly longer than analogous cis-bonds in accordance with the structural consequences of the trans-effect of a multiply bonded oxo ligand.