Degree of ring substitution

The stability of phosphaferricinium ions in solution is low cyclic voltammetry reveals that it decreases as the polarity of the medium rises or the degree of ring substitution falls [33]. The parent diphosphaferrocene evolves chemically under electrochemical oxidation in CH2C12, MeCN, and DMSO and is only stable in solvents such as propylene carbonate [33]. Compounds 24 and 25 are reversibly oxidized in dichloromethane but decompose in DMF, probably to the corresponding l,l -biphosphole (Eq. 20) [33] ... 

The reactivity of a liquid-solid-liquid triphase reaction (i.e., polymer-supported catalytic reaction) is influenced by the structure of the active sites, particle size, degree of cross-linkage, degree of ring substitution, swollen volume, and spacer chain of a catalyst pellet. In the past, the characteristics of a triphase reaction, subjected to the mass transfer limitation of the reactants and ion-exchange rate in the aqueous phase, have been discussed [146,158,162,178,179]. The ion-exchange rate in the aqueous phase affects the reactivity of the triphase reaction. 

In the case of the basic lead salts, the small degree of ring substitution and the low level of methylol/ether/methylene content indicates that formaldehyde has been consumed by a side reaction. The more acidic anions, on the other hand, produce large amounts of methylene linkages. Efficient production of benzylic ether linkage, however, is obtained with lead salts of perffuoro carboxylic acids. 

Uranocenes with greater degrees of ring substitution have been prepared from the dianions of more highly substituted cyclo-octatetraenes. Thus,... 

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