Metalloorganic compounds

Metalloorganic compounds of zinc, cadmium, and lithium can be added, just as the Grignard compounds, to the NN double bond of diazirines. ... 

CH3 -Zn with superstoichiometric (defect) zinc atoms (Zn -impurity centres of conductivity). The larger is the electric positivity of the metal in these complexes, the larger is the ionicity of the carbon-metal bond, carbon being at the negative end of the dipole. Thus, in the case of C - K bond, ionicity amounts to 51%, whereas for C - Mg and C - Zn bonds ionicity amounts to 35% and 18%, respectively [55]. Consequently, metalloorganic compounds are characterized by only partially covalent metal-carbon bonds (except for mercury compounds). 

A special case is when the electrochem-ically active components are attached to the metal or carbon (electrode) surface in the form of mono- or multilayers, for example, oxides, hydroxides, insoluble salts, metalloorganic compounds, transition-metal hexacyanides, clays, zeolites containing polyoxianions or cations, intercalative systems. The submonolayers of adatoms formed by underpotential deposition are neglected, since in this case, the peak potentials are determined by the substrate-adatom interactions (compound formation). From the ideal surface cyclic voltammetric responses, E° can also be calculated as... 

As observed by D. Johnson and J. Stiegler, "Polymer-precursor routes lor fabricating ceramics offer one potential means or producing reliable, cost-effective ceramics. Pyrolysis of polymeric metalloorganic compounds can be used to produce a wide variety of ceramic materials." Silicon carbide and silicon oxycarbide fibers have been produced and sol gel methods have been used In prepare line oxide ceramic powders, such as spherical alumina, as well as porous and fully dense monolithic forms. 

To improve the thermal stability of PVC, it is common to add stabilizers, generally metalloorganic compounds, in concentrations of 1-5 parts per 100 parts of PVC. Although the cis-1,4-polybutadiene grafted PVC, in the absence of an added stabilizer, yielded essentially colorless or only faintly discolored films, completely colorless films were obtained when the conventional stabilizers were added in concentrations of 0.1-0.3 parts per 100 parts of modified PVC. Organotin stabilizers were not necessary and, in some cases, actually resulted in greater color development than when they were absent. 

Yu. Shmidt, Metalloorganic Compounds, Onti-KhimTeoret, Leningrad, 1937, p. 377. 

T. G. Brilkina and V. A. Shushunov, in Reactions of Metalloorganic Compounds with Oxygen and Peroxides, Science, Moscow, 1966 Chem. Abstr., 71, 30583a (1969). 

A. Kocheshkov, Synthetic Methods in the Field of the Metalloorganic Compounds of the Group TV Elements, Russ. Acad. Sd., Moscow, 1947 Chem, Abstr., 47, 6434g (1953). 

B. M. I. Kabachnik, Metalloorganic Compounds and Radicals, Science, Moscow, 1985. 

A. N. Nesmeyanov and K. A. Kochetkov, Synthetic Methods in the Field of Metalloorganic Compounds, USSR Academy, Moscow, 1945. 

Samaan, Samir. Methods in Organic Chemistry (Houben-Weyl) Vol. 13, Pt. 8 Metalloorganic Compounds, Arsenic, Antimony, Bismuth Georg Thieme Verlag, Stuttgart, 1978. 

The configuration of Willstatter s a -cocaine has now been shown to be 3j8-benzoyloxy-3a-methoxycarbonyltropane by adopting the method of oxazine formation of the nor derivative of a -ecgonine methyl ester. This latter had been obtained from tropinone by the cyanohydrin route. Obviously the cyanide ion attacks the ketone from the a-direotion in contrast with metalloorganic compounds, which carry out nucleophilic attack from the nonhindered jS-position (130). 

The principal technical problems associated with converting crude oil into ethylene and other light olefins and aromatics stem from conversion of the heavier fractions and in particular the heavy residues which contain asphaltenes, metalloorganic compounds, etc. Several approaches can be taken to solve this problem. 

Prepolymers are produced by the condensation of aryl alkyl ethers are aryl alkyl halides or other aromatic, heterocyclic, or metalloorganic compounds in the presence of Friedel-Crafts catalysts ... 

Processes of electrochemical reduction, oxidation, and synthesis of metalloorganic compounds have been investigated intensively. Many metalloorganic complexes and catalysts may be obtained via electrochemical methods. Electrolytic redox processes may be accompanied by reductive elimination or homolytic cleavage of the M — C bond and the formation of various products of radical reactions ... 

---