Metal-halide complexes

Complexes with chelating polysulfidc ligands can be made either by reacting complex metal halides with. solutions of polysulfides or by reacting hydrido complexes with elemental... 

Strictly speaking, a catalyst is some species directly involved in the catalytic cycle and, in the reactions discussed here, these species are usually low-valent, coordinatively unsaturated transition metal complexes. Metal halides, e-.g., chloroplatinic acid, PdCl, etc., although often claimed as catalysts are more properly catalyst precursors, since in the presence of silyl hydrides the metal halides are reduced. If no stabilizing ligands, e.g., olefins, phosphines, etc. are present, the reduction normally proceeds to a finely divided form of the metal or to insoluble metal silyl/hydride clusters which may act as heterogeneous catalysts. 

Complex metal halides with the inverse spinel structure see Oxides Solid-state Clieinistijj, Li2MCl4 with M = Mg, Cr, Mn, Fe, Co, and Cd, are also examples of halide-type Li+ conductors these materials have conductivities of the order of lO- Scm-i at 300°C.8i... 

Commercially important photoinitiators for crosslinking by cationic polymerization are onium salts, particularly the thermally and hydrolytically stable diaryliodonium and triarylsulfonium salts,and mixed ligand arene cyclopentadienyl metal salts with complex metal halide anions. Direct and sensitized photolysis of these systems have been reviewed " and are discussed in detail in Volume 4, Chapter 20. 

Although the structure of [SsN] has not been established by X-ray crystallography, the vibrational spectra of 30% N-enriched [SsN] suggest an unbranched [SNSS] (5.22) arrangement of atoms in contrast to the branched structure (Dsh) of the isoelectronic [CSs] and the isovalent [NOs] ion (Section 1.2). Mass spectrometric experiments also support the SNSS connectivity in the gas phase.Many metal complexes are known in which the [SsN] ion is chelated to the metal by two sulfur atoms (Section 7.3.3). Indeed the first such complex, Ni(S3N)2, was reported more than twenty years before the discovery of the anion. It was isolated as a very minor product from the reaction of NiCl2 and S4N4 in methanol. However, some of these complexes, e.g., Cu and Ag complexes, may be obtained by metathetical reactions between the [S3N] ion and metal halides. 

A variety of complexes of the thionyl imide anion [NSO] with both early and late transition-metal complexes have been prepared and structurally characterized. Since both ionic and covalent derivatives of this anion are readily prepared, e.g., K[NSO], McsMNSO (M = Si, Sn) or Hg(NSO)2, metathetical reactions of these reagents with transition-metal halide complexes represent the most general synthetic method for the preparation of these complexes (Eq. 7.10 and 7.11). ... 

Complexes of the sulfenamido anion [RSNR ] with several transition metals [Zr(IV), Ti(IV), Mo(VI), W(Vf), Ni(If), and U(IV)] are known.They are prepared by the reaction of the lithium derivative of the sulfenamido anion with a metal halide complex. A selenium complex W(N Bu)2( BuNSePh)2 has been obtained in a similar... 

The combination of hard (A) and soft (5) coordination in the 1,5-P2N4S2 ring system leads to a diversity of coordination modes in complexes with transition metals (Lig. 13.1). In some cases these complexes may be prepared by the reaction of the dianion [Ph4P2N4S2] with a metal halide complex, but these reactions frequently result in redox to regenerate 13.3 (L = S, R = Ph). A more versatile approach is the oxidative addition of the neutral ligand 13.3 (L = S) to the metal centre. 

The alkali metal halides, particularly NaCl and KCl, find extensive application in industry (pp. 71 and 73). The hydrides are frequently used as reducing agents, the product being a hydride or complex metal hydride depending on the conditions used, or the free element if the hydride is unstable. Illustrative examples using NaH are ... 

More complex is the hydrolytic disproportionation of the molecular halogens themselves in aqueous alkali which is a commercial route to several alkali-metal halides ... 

Structure-chemical aspects of complex formation in metal halide-macrocyclic polyether systems 99UK136. 

Other RhX(CO)(PPh3)2 compounds can be made as shown in Figure 2.23 metathesis with an alkali metal halide or pseudohalide is often convenient, but the most versatile route, as with the iridium analogues, is a two-stage process in which the fluoro complex is first prepared, the fluorine then being readily displaced. 

Metal complex-organic halide redox systems... 

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