Halide complexes and clusters

A. Organometallic Complexes Halide Complexes and Clusters Complexes with Nitrogen Ligands Phosphine, Arsine, and Related Complexes Complexes with Sulfur Ligands Nitrosyl and Thionitrosyl Complexes Technetium(III)... 

In general, correlation corrections are larger for a holes than for ir holes. It is not unusual for these differential correlation effects to change the predicted order of final states. Heterocyclic organic molecules with nitrogen-centered, nonbonding electrons are not alone in this respect. Organometallics, transition metal complexes, and clusters of metal oxides and metal halides also require this kind of theoretical interpretation. 

These two elements have very similar chemistries, though not so nearly identical as in the case of zirconium and hafnium. They have very little cationic behavior, but they form many complexes in oxidation states II, III, IV, and V. In oxidation states II and III M—M bonds are fairly common and in addition there are numerous compounds in lower oxidation states where metal atom clusters exist. An overview of oxidation states and stereochemistry (excluding the cluster compounds) is presented in Table 18-B-l. In discussing these elements it will be convenient to discuss some aspects (e.g., oxygen compounds, halides, and clusters) as classes without regard to oxidation state, while the complexes are more conveniently treated according to oxidation state. 

T. Waters, X.-B. Wang and L.-S. Wang, Coord. Chem. Rev., 2007, 251, 474. Review describing the use of electrospray to transfer negatively charged transition metal complexes to the gas phase for photoelectron spectroscopy. Examples discussed include square planar and octahedral halide complexes, metal-metal bonded species, transition metal bis(diihiolene) complexes, and mononuclear and polynuclear iron-sulfur clusters. 

There are many examples of borohydride compounds of these metals, e.g., Cu, Ag, Zn and Cd-BH as neutral and anionic complexes in which the mode of bonding of BH is dependent on the coordination number of the metaP. Higher borane anions also combine with Cu and Ag, yielding both neutral and anionic complexes. Although no borohydrides of Au are isolated, treatment of Au-halide complexes with, e.g., NaBH, is a standard method for the preparation of Au-cluster compounds Copper(I) hydride, first reported in 1844, has the ZnS structure [d(Cn-H) = 0.173 nm (1.73 A) d(Cu-Cu) = 0.289 nm (2.89 A)] and decomposes to the elements when heated. At >100°C the decomposition is explosive. 

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