Functional groups, bridging

Additions constitnte the largest group of alkene reactions and lead to saturated products. Through addition, we can take advantage of the fact that the alkene functional group bridges two carbons, and we can elaborate on the molecular stmcture at either or both of these carbons. Fortunately for us, most additions to the rr bond are exothermic They are almost certain to take place if a mechanistic pathway is available. 

When the two bridges not containing the substituent are of equal length, this convention cannot be applied, but in some cases a decision can still be made for example, if one of the two bridges contains a functional group, the endo isomer is the one in which the substituent is closer to the functional group ... 

The reactions of the six-membered chlorocyclophosphazene were studied with a number of aliphatic diamines (169 175), aromatic diamines (176), aliphatic diols (177-179), aromatic diols (180,181) and compounds containing amino and hydroxyl functional groups (169,170,182). This subject has been reviewed (11,16,20). There are at least five different reaction products that are possible (Fig. 19). Replacement of two chlorine atoms from the same phosphorus atom produces a spirocyclic product. Replacement of two chlorine atoms from two different phosphorus atoms in the same molecule produces an ansa product. Reaction of only one end of the difunctional reagent, resulting in the substitution of only one chlorine atom, leads to an open-chain compound. Intermolecular bridged compounds are formed when the difunc-... 

Improve adhesion of dissimilar materials such as polymers to inorganic substrates. Also called primers. Primers generally contain a multifunctional chemically reactive species capable of acting as a chemical bridge. In theory, any polar functional group in a compound may contribute to improved bonding to mineral surfaces. However, only a few organofunc-tional silanes have the balance of characteristics required... 

C A pitch insoluble in benzene but soluble in benzene/ ethanol azeotrope 40 Consists almost entirely of aromatic fragments attached to phenol by methylene bridges. These fragments are larger than in fraction B as they contain polyaromatic groups. It has more oxygen functional groups than B. 

Further studies have shown that the degree of aggregation, and hence the number of active sites, is a function of the alkoxide substituent.813 For example, in (270) one of the i.vo-propoxide groups bridges two aluminum centers the other three are terminal ligands and all three initiate the ROP of CL. Less aggregated species such as (270) generally exhibit simple first order kinetics. 

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