Complexes of the Transition Metals with

Complexes of the transition metals with phosphines, arsines and stibines. G. Booth, Adv. Inorg. Chem. Radiochem., 1964, 6,1-69 (460). 

Complexes of the Transition Metals with Phosphines, Arsines, and Stibines G. Booth... 

S. G. Murray and F. R. Hartley, Chem. Rev., 1981, 81, 365. Review of thio-, seleno- and telluro-ether complexes of the transition metals with 748 references. 

Complexes of the transition metals with phosphines, arsines and stibines... 

With a few exceptions, only the binary dithiocarbamato complexes of the transition metals and those of group lib are included, leaving it to the reader, to determine what has to be considered as usual or unusual. 

In general the stability of hexahalo complexes of the transition metals tends to decrease appreciably with increasing atomic number and with increasing size of the halide ligand. (See Ref. (7) for discussion of the 3d situation.) Thus for example in the 4 d series MF - species are known for Mo, Ru, Rh, and Ag, but MCI - ions have been reported only for the first three of these metals. Similarly in the 5 d series MFelements from Ta to Au, but MCI 6 species have been reported only as far as WCle, whilst MFg compounds extend from W to Pt, but MCle systems only up to ReClg. 

An excellent review article (460) has covered much of the literature concerning Me2SO complexes of the transition metals up to 1969. In consequence, only the major points prior to this period will be discussed, together with more recent developments and comments on complexes of the higher sulfoxides. 

This section reviews the developments in the chemistry of monoborane complexes of the transition metals especially borohydride and hydridoborate complexes. Although such complexes are not strictly metallaboranes in the sense that they are not cluster species, they are included here as they share many similarities with polyborane species of the transition metals such as three-center two-electron bonding. Additionally, as will be shown in Section 3.04.3.1 borohydride species can also be intermediates in the formation of larger M By clusters. In this chapter, three-coordinate monoborane species, which are best considered as cr-complexes between a transition metal and HBR2 or metal-boryl (M-B) species, are not considered. 

During the period 1965-1975 the chemistry of the 1,2-dithiolene complexes of the transition metals was the subject of considerable study.86,87,91-98 However, during this period of great activity few complexes of the early transition metals were reported aside from those of vanadium. The problem had much to do with synthetic procedures, since reaction of, say, the anhydrous metal chlorides with the dithiolene or its sodium salt did not prove successful. However, the use of metal dialkylamides99 did result in clean reactions (e.g. equation 21). 

Published data on the volatility of complexes of the transition metals including chromium with bidentate sulfur and sulfur-oxygen donor ligands have been summarized.1042... 

The orbitals d, dt and d can, however, be used in case that the central atom of the complex forms multiple bonds with the ligands. Some of the octahedral complexes of the transition metals contain bonds with a large amount of double-bond character. These complexes will be discussed in Chapter 9. 

The problem of the stability of the complexes of the transition metals was for many years a puzzling one. Why is the cyanide group so facile in the formation of complexes with these elements, whereas the carbon atom in other groups, such as the methyl group, does not form bonds with them Why do the transition metals and not other metals (beryllium, aluminum, etc.) form cyanide complexes In the ferro-... 

By far the greatest attention has been to the complexing of the transition metal ions, often with surprising results. Thus, Cu11 can be shown to bind to N-7 of the adenine moiety of ATP and yet it can considerably enhance the hydrolytic cleavage of the phosphate bonds under the same conditions. Earlier suggestions were that chelate formation occurred via the N-7 and phosphate O... 

The reaction of phenylhydrazine with copper(II) chloride in aqueous solution gives [Cu4Cl4(PhNNH)] (13) and the reactions of 1,2-disubsti-tuted hydrazines with copper(II) salts give complexes such as [Cu2-Cl2(MeNNMe)l (46, 142). The reaction of substituted hydrazines (or lithiated, substituted hydrazines) with halido complexes of the transition metals can yield diazene complexes. Complexes of Ni, Pd, Pt (147, 199,213), and Rh (209) have been prepared in this manner [Eq. (25)]. 

An additional study on the same system has been reported, including a comparison of direct electrochemical and conventional chemical dissolution of metallic copper in TMTD solutions in various solvents under conditions of simultaneous ultrasonic treatment of the reaction system [133,620]. It has been shown that the system TMTD-copper-solvent could serve as a perfect model to study the influence of simultaneous application of ultrasonic treatment (see Sec. 3.5) on the syntheses of complexes of the transition metals in different nonaqueous solutions, by using and testing several techniques [620]. Several other studies on the interaction of copper and iron species with thiruam sulfides have also been reviewed [621]. 

Considering the mechanistic rationales of the transition metal-catalyzed enyne cycloisomerization, different catalytic pathways have been proposed, depending on the reaction conditions and the choice of metal catalyst [3-5, 45], Complexation of the transition metal to alkene or alkyne moieties can activate one or both of them. Depending on the manner of formation of the intermediates, three major mechanisms have been proposed. The simultaneous coordination of both unsaturated bonds to the transition metal led to the formation of metallacydes, which is the most common pathway in transition metal-catalyzed cycloisomerization reactions. Hydrometalation of the alkyne led to the corresponding vinylmetal species, which reacts in turn with olefins via carbometalation. The last possible pathway involves the formation of a Jt-allyl complex which could further react with the alkyne moiety. The Jt-allyl complex could be formed either with a functional group at the allylic position or via direct C-H activation. Here the three major pathways will be discussed in a generalized form to illustrate the mechanisms (Scheme 8). 

There are many other Prussian blue analogs for which the visible spectrum is complex and not understood. Heavy metal ferricyanides and hexacyano complexes of other transition metals with less than d configurations are in this class due to the presence of ligand-metal charge transfer processes. 

Such hybridization is possible with other sets of orbitals indeed most covalent bonds form from hybridized orbitals. Thus, for an atom forming six covalent bonds (for example, sulfur in SF6), we speak of spzd2 hybridization—that is, six bonds derived from a combination of one s, three p, and two d orbitals. Similarly, for an atom forming five covalent bonds (for example, phosphorus in PCls vapor), we may speak of spzd hybridization. A number of workers describe complexes of the transition metals in an analogous manner but here the description is not a good one, for it glosses over some important complicating features associated with such complexes (see Chap. 22). 

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