The chemistry of heteroallene and heteroallyl derivatives of rhenium. Part 2. Reactivity of [ReO(OR)Cl2(PPh3)2](R = Me or Et) with RNCS (R = Ph or p-MeC6H4). Crystal structure of the thiazetidine rhenium(V) complex [ReOCl2(PPh3){p-MeC6H4NC(OEt)–S}]

Abstract

The complex [ReO(OR)Cl₂(PPh₃)₂](R = Me or Et) reacts with an excess of RNCS (R = Ph or p-MeC₆H₄) to give the thiazetidine complexes [ReOCl₂(PPh₃){RNC(OR)–S}] obtained by formal insertion of the heterocumulene molecule into the Re–OR bond. The crystal structure of the complex [ReOCl₂(PPh₃){p-MeC₆H₄NC(OEt)–S}] was determined by X-ray crystallography. The compound is triclinic, space group P with a= 12.991(5), b= 11.394(5), c= 10.024(5)Å, α= 93.53(3), β= 100.29(3), γ= 77.74(3)°, and Z= 2. The structure was refined to R= 0.035 for 4 626 independent reflections. The Re atom is six-co-ordinate distorted octahedral. The organic ligand is chelated through the nitrogen and sulphur atoms and makes with the metal a roughly planar four-membered ring. Selected bond distances are: Re–O 1.671(4), Re–P 2.488(2), Re–Cl 2.381(2) and 2.437(2), Re–N 2.087(5), and Re–S 2.406(2)Å.