THERMAL-DECOMPOSITION OF (C6ME6)RU(MU(4)-C4ME4S) AND RELATED REACTIVITY AND STRUCTURAL STUDIES

The paper focuses on selected aspects of the chemical behavior of (C6M e6)Ru(eta4-C4Me4S) (1). Thermal decomposition of 1 in saturated hydroc arbon solutions yields the trinuclear product (C6Me6)3Ru3(C4Me4S)2 (2a ) which has been further characterized by single crystal X-ray diffrac tion. The molecule is centrosymmetric with two (C6Me6)Ru(C4Me4S) entit ies coordinated through their sulfur atoms to a central (C6Me6)Ru unit . When the thermolysis is conducted in aromatic solvents, we also obse rved products resulting from arene exchange such as (arene)(C6Me6)2Ru3 (C4Me4S)2, where arene = C6D6 (2b), toluene (2c). The (C6Me6)3 and are ne-exchange products are formed competitively, not consecutively. Comp ound 2a is protonated by NH4PF6 to give the hydride [(C6Me6)3RU3(C4Me4 S)2H][PF6] ([2aH]PF6). Compound 2aH+ is structurally dynamic in soluti on resulting from restricted rotation about the Ru-S axis. Compound 1 decomposes in the presence of H-2 to give the dinuclear dihydride (C6M e6)2Ru2(C4Me4S)H2 (3), assigned an unsymmetrical structure where one ( C6Me6)Ru center is bound to two hydrides and a sulfur atom, while the second (C6Me6)Ru is coordinated in an eta4-mode to the thiophene.