Dithiolate complexes of manganese and rhenium: X-ray structure and properties of an unusual mixed valence cluster Mn-3(CO)(6)(mu-eta(2)-SCH2CH2CH2S)(3)

Treatment of Mn-2(CO)(10) with 3,4-toluenedithiol and 1,2-ethanedithiol in the presence of Me(3)NO(.)2H(2)O in CH2CI2 at room temperature afforded the dinuclear complexes Mn-2(CO)(6)(mu-eta(4)-SC6H3(CH3)S-SC6H3(CH3)S) (1), and Mn-2(CO)(6)(mu-eta(4)-SCH2CH2S-SCH2CH2S) (2), respectively. Similar reactions of Re-2(CO)(10) with 3,4-toluenedithiol, 1,2benzenedithiol, and 1,2-ethanedithiol yielded the dirhenium complexes Re-2(CO)(6)(mu-eta(4)-SC6H3(CH3)S-SC6H3(CH3)S) (3), Re-2(CO)(6)(mu-eta(4)-SCH2SC6H4S) (4), and Re-2(CO)(6)(SCH2CH2S-SCH2CH2S) (5), respectively. In contrast, treatment of Mn2(CO)10 with 1,3-propanedithiol afforded the trimanganese compound Mn-3(CO)(6)(mu-eta(2)-SCH2CH2CH2S)(3) (6), whereas Re2(CO)10 gave only intractable materials. The molecular structures of 1, 3, and 6 have been determined by single-crystal X-ray diffraction studies. The dimanganese and dirhenium carbonyl compounds 1-5 contain a binucleating disulfide ligand, formed by interligand disulfide bond formation between two dithiolate ligands identical in structure to that of the previously reported dimanganese complex Mn-2(CO)(6)(mu-eta(4)-SC6H4S-SC6H4S). Complex 6, on the other hand, forms a unique example of a mixed-valence trimangenese carbonyl compound containing three bridging 1,3-propanedithiolate ligands. The solution properties of 6 have been investigated by UV-vis and EPR spectroscopies as well as electrochemical techniques.