M. G. Kanatzidis

Unique reactivity characteristics of Mo-coordinated S2-2 and S2-4 ligands

Abstract The synthesis of the new dithiolene complexes, [{(MeOOC)2C2S2}2Mo(μ2-S)]−2 and [OMo(S2C2(COOMe)2)2]−, is reported. These complexes are obtained by the reaction of dicarbomethoxyacetylene (DMA) with either [(S4)Mo(S)(μ2-S)2Mo(S)(S4)]2− or [(CS4)Mo(S)(μ2-S)2Mo(S)(CS4)]2− and [OMo(S4)2]2−, respectively. The reaction of [(S4)Mo(O)(μ2-S)2Mo(O)(S2)]2− with DMA results in the new dithiolene complex [{(MeOOC)2C2S2}Mo(O)(μ2-S)]−2, which is the isomeric form of the vinyl disulfide complex obtained in the reaction of the [(S2)Mo(O)(μ2-S)2Mo(O)(S2)]2− complex with DMA. The difference in reactivity between the two complexes that contain the same [Mo2O2S2]2+ core is attributed to the intrinsically different reactivity characteristics of the S2−4 and S2−2 ligands. As a result of Mo-S dπ-pπ bonding an alternation in the SS bond lengths is observed in virtually all of the structurally characterized Mo-S4 units. The consequent weakening of the SS bonds adjacent to the MoS bonds allows for the ready dissociation of S02 from the Mo-coordinated S2−4 ligands. This weakening also accounts for the facile formation of dithiolenes in cycloaddition reactions of alkynes with the Mo-S4 units. By comparison, the SS bond in side-on Mo-coordinated S2−2 ligands is strengthened as a result of depopulation of the ligand π*-orbitals. Reactions of the latter with alkynes do not proceed by cycloaddition. Instead, insertion into the MoO bond has been reported for at least one such reaction. The importance of activated polysulfide ligands in the hydrodesulfurization reaction is discussed.

The synthesis and structural characterization of Zr3(S)(ButS)10. A Zr–S cluster that contains thiolate ligands in three different modes of co-ordination

The synthesis and structural (crystallographic and spectroscopic) characterization of the new Zr3(S)(ButS)10 cluster is described.

The synthesis and structural characterization of [Et4N]3[Fe6S6(p-MeC6H4O)6{W(CO)3}2]. A hetero-polynuclear aggregate that contains the [W2Fe6S6]3+ core

The synthesis and structural (crystallographic and spectroscopic) characterization of the new heteropolymetallic [Et4N]3[Fe6S6(p-MeC6H4O)6{W(CO)3}2] cluster is described; the anion core consists of a W2Fe6 cube with the two W atoms located in opposite corners on the elongated body diagonal.