Spiro poly

Depending on the reaction conditions, the copolymer product can be isolated in the form of either polyketone as poly(l-oxo-2-raethyltrimethylene) (Chart 7.5a) or polyspiroketal as poly[spiro-2,5-(3-methyltetrahydrofuran)j (Chart 7.5b). This latter can be transformed into the thermodynamically more stable polyketone form, either thermally or by dissolution in HFIP [1, 41, 42]. 

Depending on the reaction conditions, poly(propylene-ALr-CO)s can be isolated as either the true polyketone, poly(l-methyl-2-oxo-propanediyl), or as a polyspiroketal, poly[spiro-2,5-(3-methyltetrahydrofuran)] (Scheme 22.3). The latter polymer can be transformed into the... 

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. 

Fig. 23 (a) Dependence of the hole mobility in a film of poly-spiro-bifluorene-co-benzothiazole (PSF-BT) as function of the time elapsed after charge carrier generation by a 130 fs laser pulse at different applied voltages. The horizontal lines represent the electron and hole mobilities inferred from ToF experiments, (b) Momentary mobility as a function of the averaged distance that a carrier travelled after a given time. The inset depicts the chemical structure of PSF-BT. From [154] with permission. Copyright (2009) by the American Institute of Physics... 

If at least one component of a mono- or poly-spiro compound is a fused polycyclic system, the spiro compound is named according to Rule A-41.4 or A-41.7, giving the spiro atom as low a number as possible consistent with the fixed numberings of the component systems. 

The possibility that olefin-carbon monoxide copolymers can exist in the isomeric poly-spiro ketal structure (Scheme 8.5) was recognized soon after the first synthesis of the copolymers of propene. Using dialkyl diphosphines as the modifying ligands [27], copolymers were obtained with blocks with the spiroketal form [28]. 

Poly(spiro-2,4-hepta-4,6-diene) Fractional precipitation BenzeneAsopropanol 1247... 

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. 

Fig. 17 Schematic representation of the device structures described in Refs. 107 and III a single-layer EHO-OPPE, b two-layer EHO-OPPE/poly-TPD, c single-layer EHO-OPPE poly-TPD blend, and d two-layer EHO-OPPE poly-TPDblend with additional spiro-Qux holeblocking layer, and their corresponding energy-level diagrams. The working functions of Ca (2.9 eV) and Cr (4.5 eV) were omitted. Reproduced with permission from [111]...

The speeifieation of the type of structure in a polymer is shown by an italicized prefix "ladder- or "spiro- preceding poly . 

The first structural report of an alumo-poly siloxane appeared as early as 1966 the molecule (Me2SiO)4(OAlBr2)2(AlBr) has an Si4Al2Ofi 12-membered cycle which is spirocyclically bridged by an Al-Br unit (see Fig. 3).68 Only in 2000 was the corresponding structure of the chloro-derivative (which is iso-typic to the bromo-compond) published.69 In both compounds, all silicon and aluminum atoms are tetra-coordinate with the exception of the spiro-cyclic central bromo(chloro)-aluminum -moiety, which is penta-coordinate with four oxygen bonds. 

I. 1-anthryl-l -naphthyl alkanes. II. Nicotinamide-adenine-dinucleotide (reduced) NADH. IFF Oligomers of poly-L-proline with a-naphthyl group as energy donor and dansyl group as energy acceptor. III. p-methoxy benzene and flourene chromophere in norbornadiene-spirocyio-propane frame. V and VI. Anthrone and naphthalene chromphore in spiro-compounds. 

Spiro orthoesters (92, R = Me, Ph, and H) show typical equilibrium polymerization behavior at or below ambient temperature. [92] The poly(cyclic orthoester)s derived from 92 depolymerize to the monomers, although they have sufficient strains to be able to undergo ring-opening polymerization. The polymerization enthalpies and entropies for these three monomers were evaluated from the temperature dependence of equilibrium monomer concentrations (Table 5). The enthalpy became less negative as the size of the substituent at the 2-position in 92 was increased H < Me < Ph. This behavior can be explained in terms of the polymer state being made less stable by steric repulsion between the bulky substituents and/or between the substituent and the polymer main chain. The entropy also changed in a similar manner with the size of the substituents. 

Takata et al. [99] found for two spiro orthocarbonates (119 and 121) having l,4,6,9-tetraoxaspiro[6.6]tridecane skeletons different cationic ring-opening polymerization behavior Irrespective of solvent, initiator, and temperature (from room temperature to 150°C), 119 gave polycarbonate (120), whereas 121 gave poly (ether-carbonate) (122). 

Cationic polymerization of spiro orthocarbonates leading to a poly (ether-carbonate) alternating copolymer proceeds via the trialkoxycarbenium ion as a possible propagating species. Since this type of carbenium ion was found to be quite stable, [100] the growing chain end is expected to remain living after the completion of the polymerization. [101]... 

A bis-methylene compound of a spiro skeleton structure 21 is polymerized to produce a poly(ether carbonate) 22 (Eq. (16)) I3 I4). The course of the polymerization has been explained by a scheme involving free-radical intermediates 23 and 24. 

Several organics, e.g. pristine poly(3-octylthiophene), polyfluorene, bifunctional spiro compounds and polyphenyleneethynylene derivative, have been used for fabricating photOFETs. Responsivity as high as 0.5-1 A/W has been achieved in some of these transistors. We have already discussed the bulk heterojunction concept in Chapter 5. The bulk heterojunctions are fabricated using acceptor materials with high electron affinity (such as C<5o or soluble derivatives of C6o) mixed with conjugated polymers as electron donors. PhotOFETs based on conjugated polymer/fullerene blends are expected to show... 

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