Heteronuclear compounds

Heteronuclear compounds containing gold(I) and other metal atoms which present Au -M interactions are well represented in the area of metal carbonyl clusters. The addition of a AuPR3+ or Au2(/u-P-P)2+ fragment to a metal cluster results in the formation of Au—M bonds often with retention of the cluster framework. Several reviews have been reported recently,3153-3155 and so it will not be treated here. Some representative examples are found in Figure 26. 

There is an important class of gold compounds in which the formal oxidation state is intermediate between 0 and +1. They can be homo- or heteronuclear compounds, for which excellent reviews have been published recently.3153-3155,3211... 

The pyrazole phosphazine ligand, hexakis(3,5-dimethylpyrazolyl)cyclotriphosphazene (16) forms a dizinc complex, that has been structurally characterized, and the analogous copper zinc complex.158 Two ZnCl2 units are coordinated, one distorted tetrahedral and one distorted trigonal-bipyramidal, separated by 7.51 A. Cu1 and ZnCl2 can also be coordinated giving a heteronuclear compound with a Zn Cu separation of 6.798 A. 

In contrast to the unsuccessful early attempts to produce [W2(02CR)4], the heteronuclear compound [MoW(02CCMe3)4] was obtained by reacting a 3 1 mixture of W(CO)6 and vlo(CO)6 in refluxing dichlorobenzene.334 The heteronuclear complex was freed from Mo2(02CCMe3)4] by careful oxidation with I2. Structure analysis of MoW(02CCMe3)4]I-MeCN shows the expected idealized Dih symmetry with a short W—Mo separation of 2.194 A. The iodide ion is coordinated to the W atom and the MeCN molecule is coordinated to the molybdenum atom. 

The considerable role of synthetic methods—in particular, direct gas-phase [11,15-18] and electrochemical [11,17,19] techniques—in controlled creation of coordination compounds of various types (molecular and r n-Ti-complexes, chelates, and homo- and heteronuclear compounds) is discussed. Particular attention is given to the complex compounds having standard and nonstandard coordination modes of the most widespread (typical) ligands, for example a(N)- and ji(ri6-C)-complexes... 

Examples of heteronuclear compounds containing terminally bonded... 

The heteronuclear compound P4S3, which has the same structure as P3" but with the (i2 P groups replaced by S, has also been examined. It reacts with Cp2Cr2(CO)6 to give a mixture of CpCr(CO)2H, Cp4Cr4(CO)9P4S3, [CpCr(CO)2]2S, and CpCr(CO)2P3.391 The E7 framework is not retained for the heteroatomic species. 

Photolysis of mixed solutions of homonuclear compounds produces heteronuclear species photolysis of heteronuclear compounds in inert solvents produces homonuclear species (106-108,115) ... 

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds... 

Coal tar creosote consists of aromatic hydrocarbons, anthracene, naphthalene, andphenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, daik brown to black residue that contains PAHs and their methyl and polymethyl derivatives, as well as heteronuclear compounds. 

Some carbyne compounds may give /i-carbyne complexes as a result of the existence of an equilibrium between monomeric and dimeric species or due to reactions with other complexes. This makes it possible to prepare heteronuclear compounds. 

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