Bridges and bridging

Figure 24.12. Typical bridges and bridge configurations of flush bridge initiators.

Intermediate heterocyclic ylides may be stabilized by [1,2]- or [2,3]- rearrangements (Scheme 5). The [l,2]-shift may result in expelling an ylide heteroatom from the initially formed ylide (Scheme 6). The 1,3-dipolar cycloaddition of ylides generated by carbene cyclization onto the heteroatom of the C=Z double-bond allows an additional ring to be formed and provides a route to bridged and bridged-fused systems (Scheme 7). 

The synthesis of bromoantimonate(iii) species from SbBr3 and amine hydrobromides, both in the absence of solvent and in hydrobromic acid solution, has been reinvestigated/ The structure of pyH" SbBrJ is similar to that of the corresponding chloride, containing infinite chains of antimony atoms linked by bromine atoms in a distorted octahedral environment/ The Sb—Br distances are 2.563 and 2.795 A for the non-bridging and bridging atoms, respectively, and the octahedral arrangement is completed by an Sb—Br distance of 3.230 A. 

Applications of advanced fibre-reinforced polymer (FRP) composites in bridge engineering rehabilitation of metallic bridge structures, all-FRP composite bridges, and bridges built with hybrid systems... 

Abstract This chapter continues the discussions of the development of advanced polymer composite material applications associated with bridge engineering. It focuses on the rehabilitation of metallic bridge structures, all-FRP composite bridges and bridges built with hybrid systems. Chapter 16 covered the materials used in FRP composites, in-service properties and applications of FRP composites in bridge enclosures, the rehabilitation of reinforced and prestressed concrete bridge beams and columns. 

Little was known about the influence of the bridge and bridge substituent(s) on the catalytic performance with respect to the molecular weight of the resulting polymer until the advent of the syndiotactic-selective metallocene catalyst systems. The following two sections describe the modifications of the size and substituents of the inter-annular bridge in complex 1 and their impact on the catalytic performance and resulting s-PP. 

---