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 cyclohexylamino)-1-cyclopentenedi thiocarboxylate], with the ligand HL' coordinated as a monodentate to rhenium(V) through the neutral thiocarbonyl sulfur atom in the positio n 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 reac tion solutions immediately after cooling to room temperature. The comp ounds cis-ReOCl3(PPh3) (HL')-Me2CO were isolated as dark green crystal s from the filtrate on slow evaporation of the solvent at room tempera ture over a period of 2 days. Physicochemical, infrared, H-1 NMR and s pectroscopic data are reported.