THE SYNTHESES, STRUCTURES, AND STEREODYNAMICS OF [3]-FERROCENOPHANE COMPLEXES .3. RHENIUM TRICARBONYL HALIDE-COMPLEXES, FAC-[REX(CO)3((C5H4ECH3)2FE)] (X = CL, BR, I, E = S, SE) - CRYSTAL-STRUCTURE OF CHLORO-1,1'-BIS(METHYLTHIO)FERROCENETRICARBONYLRHENIUM

The complexes fac-[ReX(CO)3{(C5H4ECH3)2Fe}] (X Cl, Br, I; E S, Se) have been synthesised. A 1H NMR study of their solution properties showed that pyramidal inversion of the coordinated chalcogen atoms was rapid on the NMR timescale at ambient temperatures, but at low temperatures (ca. -70°C) the complexes existed as mixtures of meso and dl species, with the former predominating, particularly in the sulphur ligand complexes. Low temperature 2D-EXSY studies and variable temperature 1D bandshape analyses yielded accurate chalcogen inversion energies for both meso-1 → dl-1 and dl-1 → dl-1 exchanges. Values of ΔG‡(298 K) for these interconversions were, respectively, in the regions of 43 and 46 kJ mol-1 (S inversion) and 63 and 66 kJ mol-1 (Se inversion). The crystal structure of chloro-1,1′-bis(methylthio)ferrocenetricarbonylrhenium has been determined. The crystals have space group P1, with a 9.030(1), b 14.252(2), c 7.554(1) Å, α 76.58(1)°, β 104.73(1)°, γ 107.08(1)° and Z = 2. Least-squares refinement gave R = 0.030 for 2930 reflections. The ReS bond lengths are 2.504(4) and 2.512(4) Å and the SMe groups adopt a meso relationship analogous to the preferred solution structure. The SReS bond angle is 80.0(2)° and the non-bonded SS separation. © 1990.