TECHNETIUM AND RHENIUM COMPLEXES WITH THIOETHER LIGANDS .6. SYNTHESISAND STRUCTURAL CHARACTERIZATION OF MIXED-LIGAND OXORHENIUM(V) COMPLEXES CONTAINING BIDENTATE DITHIOETHERS AND MONOTHIOLATO LIGANDS

Neutral oxorhenium(V) complexes with dithioether Ligands of the genera l formula [ReOX3(RS[CH2](2)SR)], X = Cl, Br, R = nBu, Et, Bzl were syn thesized. Ammonium perrhenate reacts in concentrated hydrochloric acid with dithiaalkanes (RS[CH2](2)SR, R = nBu, Et, Bzl) dissolved in glac ial acetic acid to give octahedral complexes of the type [ReOCl3(RS[CH 2](2)SR)] (1a-c). In concentrated hydrobromic acid, nBu-S(CH2)(2)S-nBu leads to the corresponding tri-bromo complex (2). The X-ray structure of 2 shows a distorted octahedron with facial coordination of the bro mide ligands. The sulfur atoms are cis coordinated to the terminal oxy gen. Dissolution of 1a (R = nBu) in methanol leads to the substitution of the chloride trans to the oxo ligand by a methoxy group. The resul tant complex [ReOCl2(MeO)(n-Bu-S[CH2](2)S-nBu)] (3) is stable and can be isolated from methanolic solution, but changes to the mu-oxo-bridge d dirhenium complex -oxobis[dichloro(5,6-dithiadodecane)oxorhenium(V)] (4) when dissolved in other organic solvents. 1a reacts with an exces s of benzenethiol by substitution of two chlorides to give the mixed-l igand complex nethiolato)chloro(5,8-dithiadodecane)oxorhenium(V) (5a). The related 4-methylbenzenethiolato complex 5b was synthesized starti ng from the mu-oxo complex 4. X-ray crystal structure determination of 5b shows the equatorial arrangement of the sulfur atoms. The trans po sition to the oxygen atom is occupied led by a chloride ion.