Spiro-polymers

The backbone here is made up of six-membered rings in which the two rings share a common atom. These are called spiro polymers. 

Spiro polymers are also sometimes classified as ladder polymers, and molecules in which the ladder structure is interrupted by periodic single bonds are called semiladders. Consisting entirely of fused ring structures, ladder polymers possess very rigid chains with excellent thermal stability. 

Recommendations on additional aspects of macromolecular nomenclature such as that of regular double-strand (ladder and spiro) and irregular single-strand organic polymers continue to be pubHshed in I ure and Applied Chemistty (100,101). Recommendations on naming nonlinear polymers and polymer assembHes (networks, blends, complexes, etc) are expected to be issued in the near future. 

Nitro-substituted indolino spiroben2opyrans or indolino spironaphthopyrans are photochromic when dissolved in organic solvents or polymer matrices (27). Absorption of uv radiation results in the colorless spiro compound [1498-88-0], C22H2gN202, being transformed into the colored, ring-opened species. This colored species is often called a photomerocyanine because of its stmctural similarity to the merocyanine dyes (see Cyanine dyes). Removal of the ultraviolet light source results in thermal reversion to the spiro compound. 

Related to the ladder polymers are the spiro polymers as typified by the reaction product of cyclo-octadecane-1, 10-dione with pentaerythritol Figure 29.22). 

This is also a further example of a spiro-polymer as well as being of the inorganic backbone type. 

Many other reagents for converting alkenes to epoxides,including H2O2 and Oxone , VO(0-isopropyl)3 in liquid C02, ° polymer-supported cobalt (II) acetate and 02, ° and dimethyl dioxirane.This reagent is rather versatile, and converts methylene oxiranes to spiro-epoxides. ° ° One problem with dimethyloxirane is C—H insertion reactions rather than epoxidation. Magnesium monoperoxyphthalate is commercially available, and has been shown to be a good substitute for m-chloroperoxybenzoic acid in a number of reactions. 

Details are given of the successful construction of a novel reversible system of network polymers between bifunctional monomers by utilising the equilibrium polymerisation system of a spiro orthoester. Molecular structures were determined by NMR and IR spectroscopy. 9 refs. 

FIGURE 6.31 Spiro polymerization of a, dimer units linked by alkyl chains. Reduction of 41 converts the spiro dimer units into ethano-dimer units, resulting in polytocopherols 42. 

The spiro polymerization is a novel reaction type that uses the spiro dimerization of o-QMs to build up linear oligomers and polymers. The basic properties of the spiro dimer of a-tocopherol, that is, its fluxional structure and its ready reduction to the ethano-dimer, remain also active when such structural units are bound in the polymer. The products of the reaction, both in its poly(spiro dimeric) form (41) and in the form of the reduced polytocopherols (42), are interesting materials for application as high-capacity antioxidants, polyradical precursors, or organic metals, to name but a few. 

Finally, the spiro polymerization of molecules bearing two ortho-alkylphenol functions capable of forming o-QMs offers a wide field for reactivity and kinetic studies as well as multiple applications in polymer and material chemistry and science. 

The absorption band of the colored form of spironaphthooxazine has been measured in thermal equilibrium with the spiro form, particularly in a polar solvent at low temperature. Typical absorption spectra of the colorless and the colored form in polymer fdms are shown in Figure 1.8. 

Another example of spiro-derivatized PF was demonstrated by Bo and coworkers [319], who synthesized soluble spiro-bifluorene-based polymer 219. This polymer showed stable bright-blue PL (d>PL = 91% in toluene), and showed no green emission in the annealed film (although no device preparation has been reported as yet) (Chart 2.52). 

F.-I. Wu, R. Dodda, D.S. Reddy, and C.-F. Shu, Synthesis and characterization of spiro-linked poly(terfluorene) a blue-emitting polymer with controlled conjugated length, J. Mater. Chem., 12 2893-2897, 2002. 

Spiro-FPAl/TPBI/Bphen Cs/Al. A very low operating voltage of 3.4 V at luminance of 1000 cd/m2 was obtained, which is the lowest value reported for either small-molecule or polymer blue electroluminescent devices. Pure blue color with CIE coordinates (0.14, 0.14) have been measured with very high current (4.5 cd/A) and quantum efficiencies (3.0% at 100 cd/m2 at 3.15 V) [245]. In another paper, Spiro-FPA2 (126) was used as a host material with an OLED device structure of ITO/CuPc/NPD/spiro-FPA2 l%TBP/Alq3/LiF that produces a high luminescent efficiency of 4.9 cd/A [246]. 

U.S. 6,361,884 Partially conjugated polymers with spiro centers and their use as electro-luminescent materials... 

Finally, the unsaturated spiro ortho carbonates were been shown to undergo double ring opening in a free radical polymerization to introduce a carbonate group in the backbone of an addition polymer (19). 

The Influence of Excess Citrate. J Am Chem Soc 89 5559 333b. Spiro TG, Pape L, Saltman P (1989) The Hydrolytic Polymerization of Ferric Citrate. I. The Chemistry of the Polymer. J Am Chem Soc 89 5555... 

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