Polysulfide ligands

Reactions of metal halides with polysulfide dianions are useful methods for the synthesis of polysulfido complexes of main group elements and transition metals. In most of these reactions, similarly to other methods, the chain lengths and coordination types of the polysulfide ligands depend on the other ligands coordinated to the metal, on the ratio between the metal and sulfur, on the reaction temperature, and other parameters. 

Bridging polysulfide ligands feature in the complexes [Ru2(//-8 )(/u-82CNMe2)(82CNMe2)-(CO)2(PPh3)2] ( = 5 or 6). In the solid state, the structure of each complex is unsymmetrical as... 

Polyrotaxene complexes, 46 271-273 Polysilanes, mass spectra of, 18 251 Polysilazanes, preparation of, 6 265-272 Polysiloxanes, 42 149-150 Polysulfide metal complexes, 31 89-122 cluster structures, 31 96 compound types, 31 91-103 with coordinated polysulfide ligands, 31 91-97... 

Molybdenum complexes of polysulfide ligands are reactive and, for example, readily make and break sulfur-carbon bonds, a property undoubtedly relevant to the involvement of Mo—S... 

Complexes with chelating polysulfide ligands can be made either by reacting complex metal halides with solutions of polysuifides or by reacting hydiido complexes with elemental... 

Since (BzS)2S is very reactive, the reaction and the polysulfide ligands it produces will be enhanced. This probably accounts for the high viscosity of the solution observed after the reaction of (BzS)2S and Et2Zn at a 5 1 ratio. If the gel contains residual benzene groups, the presence of these bulky groups further enhances the linear polymerization and stability of the gel. 

We previously reported the synthesis of thiol-modified silica-polyamine composite using ethylene sulfide. Although the reaction of ethylene sulfide with WP-1 gave a material that had excellent mercury capture characteristics, this ligand is toxic and difficult to make and handle. In addition, ethylene sulfide polymerizes with itself in the presence of nucleophiles therefore, we could not tell if we were dealing with an amino-thiol ligand (Fig. 16 ) or a polysulfide ligand (Fig. 165).27... 

Reagent for deoxygenation of epoxides and peroxides, and desulfurizations of thiiranes, and polysulfides. Ligand for metals of Groups IB, IIB, IVB, VB, VIB, VIII. Used as C H soln. for extraction-separation of In (as ion-associate with InBr4 , diisopropyl ether). Liq. with garlic-like odour. Misc. org. solvs. Fp 40°. Bp 240°, Bp2o 130°. 1.4635. 

The dinuclear ion Mo2(S2) g (F - prepared from the reaction of molybdate and polysulfide solution (13) is a usehil starting material for the preparation of dinuclear sulfur complexes. These disulfide ligands are reactive toward replacement or reduction to give complexes containing the Mo2S " 4 core (Fig. 3f). 

Draganjac M, Rauchfuss TB (1985) Transition metal polysulfides Coordination compounds with purely inorganic chelate ligands. Angew Chem Int Ed Engl 24 742-757 DuBois MR (1989) Catalytic applications of transition metal complexes. Chem Rev 89 1-9 Ansari MA, Ibers JA (1990) Soluble selenides and tellurides. Coord Chem Rev 100 223-266... 

A number of structures with S-rich dianion ligands have been determined (297-299).831 832 For example, (297) can be synthesized by the reaction of [Ni(CN)4]2 with polysulfide.833 Upon further reaction with CS2 or substituted acetylenes it forms perthiocarbonato and dithiolene complexes, respectively. 

Polysulfides of several metals can be prepared by reaction of the metals with excess sulfur in liquid NH3 (group IA metals) or by heating sulfur with the molten metal sulfide. The polysulfide ion binds to metals to form coordination compounds in which it is attached to the metal by both sulfur atoms (as a so-called bidentate ligand). One example is an unusual titanium complex containing the S52-ion that is produced by the following reaction (the use of h to denote the bonding mode of the cyclo-pentadienyl ion is explained in Chapter 16) ... 

Monocyclic MS units are known for n = 3-7 and 9. Among the mononuclear complexes there is also an example where a polysulfide acts as a tridentate ligand, namely the 87 ion in (Mc3P)3M(S7) (M = Ru, Os). The OSS7 bicycle shows a similar exo-endo conformation as the ion in Sg(AsF6)2 (58). ... 

Reaction of metal complexes with S is a convenient method for directly introducing the ligand by substitution of other ligands. For example, NajS2 or polysulfide solutions can be used for this purpose (77, 107, 108, 120,146). 

The metal-ligand interaction in S complexes should he comparable to that in other complexes with sulfur-containing ligands, at least for higher values of n. Additionally, the observation that polysulfides with even n prefer coordination to closed-shell metal ions and those with odd n to open-shell ones indicates that the kind of metal-to-ligand interaction is obviously not restricted to the sulfur atoms attached directly to the metal. 

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