THE SYNTHESES, STRUCTURES AND STEREODYNAMICS OF TRANSITION-METAL COMPLEXES OF 1,1'-BIS(METHYLTHIO)RUTHENOCENE - CRYSTAL-STRUCTURE OF 1,1'-BIS(METHYLTHIO)RUTHENOCENE TETRACARBONYLTUNGSTEN

The complexes cis-[M(CO)4(LL)], fac-[ReX(CO)3(LL)] and fac-[PtXMe3(LL)], (M = Cr, Mo, W; LL = [(C5H4SCH3)2Ru]; X = Cl, Br, I) have been synthesised. A 1H NMR study of their solution properties has shown that pyramidal inversion of the coordinated sulphur atoms is rapid on the NMR timescale at ambient temperature. At low temperatures (ca. -90° C) the motion is arrested and the tungsten complex exists as a mixture of meso and dl species in approximately equal proportions, whereas the rhenium complexes are predominantly (> 94%) in the meso form. Insolubility precluded low-temperature studies on the platinum complexes. Variable temperature bandshape analyses of the tungsten complex yielded a sulphur inversion (meso → dl) value of ΔG≠ (298 K) 32.0 ± 1.0 kJ mol-1. The massive predominance of one invertomer in the case of the rhenium complexes prevented a study of the sulphur inversion by bandshape analysis. The crystal structure of 1,1′-bis(methylthio)ruthenocene tetracarbonyltungsten has been determined. The WS bond lengths are 2.571(5) and 2.565(4) Å, with a SWS bond angle of 81.1(1)°. The cyclopentadienyl rings are eclipsed and the SCH3 groups adopt a meso relationship. © 1990.