The chemistry of heteroallene and heteroallyl derivatives of rhenium. Part 1. Reactivity of mixed carbonyl(formamido)(phosphine)rhenium(I) complexes with RNCS (R = Ph or p-MeC6H4) and PhNCO. Crystal structure of the thiazetidine rhenium(I) complex [Re(CO)2(PPh3)2{PhNC(OEt)–S}]

Abstract

The formamido rhenium(I) compound [Re(CO)₂(PPh₃)₂(OCHNC₆H₄Me-p)] reacts in anhydrous benzene with an excess of PhNCS to give, after treatment with EtOH, the thioureido derivative [Re(CO)₂(PPh₃)₂{PhNC[N(C₆H₄Me-p)CHO]S}] obtained by formal insertion of the heterocumulene molecule into the Re–N bond, and also the new thiazetidine rhenium(I) derivative [Re(CO)₂(PPh₃)₂{PhNC(OEt)–S}]. The crystal structure of the latter complex was determined by X-ray crystallography. The compound is monoclinic, space group P2₁/n, with a= 15.563(5), b= 19.156(4), c= 15.139(5)Å, β= 97.66(3)°, and Z= 4. The structure was refined to R= 0.054 for 5 886 independent reflections. The Re atom has distorted octahedral co-ordination. Selected bond distances are: Re–P 1.420 (mean), Re–S 2.548(4), Re–N 2.20(1), and Re–C 1.86 Å(mean).