Synthesis and characterization of mixed-ligand oxorhenium(V) complexes with new [(PNO/S)(S)] donor atom sets

Abstract

New oxorhenium complexes with 2-(diphenylphosphanyl)-N-(2-thioethyl)benzamide (H₂PNS) and 2-(diphenylphosphanyl)-N-(2-hydroxyethyl)benzamide (H₂PNO) and various monodentate thiols as co-ligands are reported. These new complexes, 1–6, have been prepared by reacting [ⁿBu₄][Re(O)Cl₄] or [Re(O)Cl₃(PPh₃)₂] with the tridentate H₂PNX (X = O, S) ligands and different monothiols. The characterization of the complexes involved IR, ¹H and ³¹P NMR spectroscopy and X-ray crystallographic analysis in the case of 1 and 2. Complexes [Re(O)(κ³-PNO)(SPh)] (1), and [Re(O)(κ³-PNS)(SPh)] (2), adopt a distorted square pyramidal geometry (δ = 3.0°, 1 and δ = 1.3° for 2), with the oxo group in the axial position and the equatorial plane being defined by the phosphorus, nitrogen and oxygen (1) or sulfur (2) atoms of the tridentate chelate and by the sulfur atom of the monothiol.