Organometallic compounds vinyl-type

In more recent years two new types of antifouling composition have been developed, using organometallic compounds as poisons. In one type, based chiefly on vinyl resin and organotin compounds (e.g. tributyltin fluoride), the poison and resin form a solid solution. As the poison dissolves from the surface of the film, more poison diffuses from deeper in the film to... 

Alkenes frequently have two kinds of C—H bonds, vinyl and allyl, that are generally more acidic than the C—H bonds of saturated alkanes. Quantitative measures of acidity are related to the chemistry of the corresponding carbanions and carbanion salts or organometallic compounds. Several methods have been used for the study of anions in the gas phase1. For many acids it is possible to measure equilibrium constants for equilibria of the type in equation 1. From such equilibrium constants with compounds RH of independently known gas-phase acidity, it has been possible to determine the acidities of a wide range of compounds2. 

In the second place, the electronic nature of the R group can modify the polarity of the carbon-metal bond. The importance of x-bonding in the structure of metal alkyls is discussed in Section III.B. As far as chemical reactivity is concerned, however, a greater electron-attracting power of R should enhance the polarity of the carbon-metal bond and thus increase its chemical reactivity. In addition, if the R group is unsaturated, the reactivity of the organometallic compound changes markedly. Situation of the unsaturation on the carbon atom of C—M bond as in phenyl, vinyl, or acetylenic R—M types usually results in some stabilization of the bond if x-metal orbital overlap can occur ... 

There are several types of Ziegler-Natta and ROMP catalysts employed for cycloolefin polymerization, the majority of them being derived from transition metal salts and organometallic compounds [4-7]. These types are grouped into unicomponent, binary, ternary, and multicomponent catalytic systems as a function of the presence or absence of the organometallic cocatalyst or other additives, each of them being differentiated on the catalyst composition and selectivity toward vinylic or ring-opened polymerization. 

A wide variety of binary catalysts of both Ziegler-Natta and ROMP type, consisting of group IV-VII transition metal salts associated with organometallic compounds, have been used in cycloolefin polymerization to manufacture high molecular weight vinylic and ring-opened polymers [4-7]. The activity and selectivity of these catalytic systems depend mainly on the nature of the transition metal and the structure of cycloolefin. 

The quasi-complex compounds, as well as the complexes discussed above, led us into a domain which was nearly terra incognita at that time, namely, the substituted (j3-chloro, j8-alkyl, )3-keto) vinyl organometallics. Thus, the simplest of metal vinyls became the objective of our work, and the vinyl, isopropenyl, propenyl, and styryl derivatives of elements such as Hg, B, Tl, Ge, Sn, Si, P, As, Sb, and Bi were studied in collaboration with Freidlina and Borisov. Apart from the procedures mentioned in Section V, vinyl-lithium and vinyl Grignard compounds were used for the synthesis. Note that the highest valence alkenyl derivatives of the type RjSb were reported by us (181-205). 

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