ISOMERIZATION IN RHENIUM(V) COMPLEXES - THE ISOLATION AND CHARACTERIZATION OF CIS AND TRANS ISOMERS OF RHENIUM(V) COMPLEXES WITH DERIVATIVES OF 2-AMINO-1-CYCLOPENTENE-1-DITHIOCARBOXYLIC ACID

The complexes trans-ReOCl3(PPh3) (HL') - Me2CO [HL' = 2-(N-ethylamino)-1-cyclopentenedithiocarboxylate and 2-(N-cyclohexylamino)-1-cyclopentenedithiocarboxylate], with the ligand HL' coordinated as a monodentate to rhenium(V) through the neutral thiocarbonyl sulfur atom in the position trans to the PPh3 molecule, were prepared under reflux conditions in acetone by the reaction of trans-ReOCl3(PPh3)2 with a molar excess of HL'. The products were isolated as light green precipitates from reaction solutions immediately after cooling to room temperature. The compounds cis-ReOCl3(PPh3) (HL')-Me2CO were isolated as dark green crystals from the filtrate on slow evaporation of the solvent at room temperature over a period of 2 days. Physicochemical, infrared, H-1 NMR and spectroscopic data are reported.