Polymer in the solid state

L. Zlatkevich, ed. Luminescence Techniques in Solid-State Polymer Research. Marcel Dekker, New Y)rk, 1989. Practical emphasis on polymers in the solid state rather than in solution. 

The miscibility of two or more polymers in the solid state can be investigated by this technique. 

Ascher and Nemny 495) found that residues of triphenyltin acetate on glass, resulting from the evaporation of acetone solutions thereof, were, on contact to houseflies, less toxic with rising concentration. As triphenyltin acetate is likely to be a self-associated polymer in the solid state [similar to trimethyltin acetate (355)] and in concentrated solutions, it was suggested 495) that the monomer, which exists in dilute solutions, is toxic to insects, and the polymer, nontoxic. Interestingly, in this connection, a triphenyltin methacrylate copolymer has 470) a very low mammalian toxicity (acute, oral LDso for mice >2000 mg/kg). 

Although dimethylberyllium is a coordination polymer in the solid state,27 it has long been known to be monomeric in the gas phase.28 It has also been found to be monomeric when synthesized from the co-condensation of laser-ablated beryllium atoms and a methane/argon mixture at 10 K.11 Formed in conjunction with several other species, including hydrides (see Section 2.02.2.4), (CH3)2Be was identified from its infrared absorption bands, which were compared to DFT-calculated frequencies (DFT = density functional theory). 

This book gives a comprehensive coverage of the synthesis of polymers and their reactions, structure, and properties. The treatment of the reactions used in the preparation of macromolecules and in their transformation into cross-linked materials is particularly detailed and complete. The book also gives an up-to-date presentation of other important topics, such as enzymatic and protein synthesis, solution properties of macromolecules, polymer in the solid state. The content and presentation of Professor Vollmert s book is more encompassing than most existing treatises, and its numerous figures and tables convey a wealth of data, never, however, at the expense of intellectual clarity or educational value. 

In the effort to make pure blue-emitting materials Shim and coworkers [146] synthesized a series of PPV-based copolymers containing carbazole (polymers 95 and 96) and fluorene (polymers 97 and 98) units via Wittig polycondensation. The use of trimethylsilyl substituents, instead of alkoxy groups, eliminates the electron donor influence of the latter and leads to chain distortion that bathochromically shifts the emission (Amax = 480 nm for 95 and 495 nm for 97). In addition, a very high PLQY was found for these polymers in the solid state (64 and 81%, respectively). Single-layer PLEDs fabricated with 95 and 97 (ITO/polymer/Al) showed EL efficiencies of 13 and 32 times higher than MEH-PPV, respectively (see also Ref. [147] for synthesis and PLED studies of polymers 99 and 100) (Chart 2.20). 

Interest in these compounds—mainly for use as weakly coordinating anions—has grown rapidly in the last decade. Many synthetic routes to CBnHi2 and its derivatives are shown in Table 17 (Figures 4 and 5). The structures of CBnH12 and its derivatives determined experimentally are summarized in Table 18. The table shows one column for cations where the anions are regarded as discrete entities within the crystal lattice and the other for cations where the anions are viewed as a fragment of a molecule or polymer in the solid state. 

The structural chemistry of the organotin halides is dominated by their Lewis acid properties and their propensity to form five- and six-coordinate complexes. Self-association may give oligomers or polymers in the solid state, which usually dissociate in solution. The structure of tricyclohexyltin chloride in the crystal is temperature-dependent. At 108 K, it has the form of a rod-like polymer with distorted trigonal-bipyramidal tin and Sn-Cl separations of 245.6(7) and 300.77(7) pm, but at 298 K, the structure is best regarded as consisting of near-tetrahedral discrete molecules.3... 

As evidence that a monolithiated compound can form an equilibrium with the corresponding dilithiated compound involved, the group of Linti and coworkers crystallograph-ically examined 9,9-dilithiofluorene (45). The molecule is formed when 9-lithiofluorene (44) is dissolved in a THF/benzene mixture by an intermolecular deprotonation yielding 45 and fluorene (43). In spite of the poor solubility of compound 45, which does not allow a characterization by NMR methods, the equilibrium is still on the side of the monolithiated compound (Scheme 16). The crystal structure of compound 45 has been reported and reveals a coordination polymer in the solid state (Figure 13). 

FIGURE 13. Molecular structure of 45 (cut-out of coordination polymer) in the solid state... 

In the solid-state structure of dilithiated fluoranthene (235), generated from 234 in dimethoxyethane at room temperature by Bock and coworkers (Scheme 82), lithium-DME units are capping the naphthalene moiety from both sides of the plane alternatingly (compound 235 forms a coordination polymer in the solid state). The metallic lithium, used for the reaction, was activated by ultrasonic irradiation. Moreover, several structures of related polysodium compounds were also characterized in the solid state . 

Oxidation of Anionic Polymers In the Solid State The ability of the macroradical and of the macroions to diffuse In the mixture, and to interreact Is responsible for the secondary products formation coupling reaction and alcoholate synthesis. To prevent the diffusion phenomenon, we have carried out the deactivation In the solid state. The living polymers have been prepared In benzene, with or without a solvating agent (THF or TMEDA) and the solution has been freeze dried before the oxygen introduction. The experimental results are collected in Table VII. 

By far the most interesting application to date is the ability to crosslink polymers in the solid state, and much research has been devoted to studying the reactions involved. The initial physical process of energy absorption and the final chemical change—formation of crosslinks—can be readily determined. However, there is still considerable doubt as to the intermediate reactions, and this problem offers an appropriate start of this review. 

In contrast, in the related ylide complexes of stoichiometry [Au2(L-L) (CH2)2S(0) NMe2 ] (L-L = dpmp, dppm, dppe) [32], the same group describes oligomerization processes in solution, even when these molecules are not polymers in the solid state. 

In considering the structure of polymers in the solid state, several issues arise. Among the major questions are ... 

For the purpose of arriving at polymeric reagents the formation of a carbon-carbon bond via radical means was desired. Trapping radicals in this way has been well known to modern organic chemists25. However, our problem in modifying PCTFE by this method was the heterogeneity of the polymer. In the solid state, PCTFE may be excluded from a solution-mediated reaction, and recovered unreacted. 

A series of novel styrene- and siloxane-based silanol polymers and copolymers were synthesized by a selective oxidation of the Si—H bond with a dimethyldioxirane solution in acetone from corresponding precursor polymers. The conversion of the Si—H to Si—OH in the polymer modification proceeded rapidly and selectively. The silanol polymers obtained in situ showed no tendency for self-condensation to form siloxane crosslinks in solution. Moreover, stable silanol polymers in the solid states were obtained by placing bulky substitute groups bonded directly to the silicon atom. It was found that the properties of these novel silanol polymers and copolymers depended largely on substituents bonded directly to the silicon atom and silanol composition in the copolymers as well. 

As pointed out in Chapter I, the NMR absorption spectrum for polymers in the solid state is generally very broad. In such cases the NMR is usually observed as the so-called broad-line spectrum. In this, the resonance is recorded by slowly sweeping the main static magnetic field H modulated with a small amplitude and frequency under a constant high-frequency subfield rotating perpendicularly to the main field. Figure 5 shows schematically the principle of the measurement for the broad-line NMR... 

This chapter is devoted to a short description of low-strain mechanical properties of polymers in the solid state and in the glass transition region, with an emphasis on the effect of crosslinking on these properties. There are three degrees of complexity in the description of this behavior, depending on the number of variables taken into account in the constitutive equations under consideration. 

Trimethyltin hydroxide and isothiocyanate, which are also self-associated polymers in the solid state, (58, 59) show rather smaller... 

The allyl lariat ether (Section 3.3) 3.132 forms complexes with both K+ and Ag+ (which are of similar ionic radius, Table 3.5). In the case of the K+ complex, as may be expected, the potassium ion is too large to fit snugly within the aza[15] crown-5 ring and lies somewhat above the donor atom plane. The exposed face of the metal atom is occupied by a PF6" anion. Similar coordination to the crown is exhibited by Ag+ but instead of an anion, the exposed face of the metal ion is coordinated to the allyl side chain of an adjacent molecule to give an infinite polymer in the solid state (Figure 3.91). 

Luminescence properties were reported for polymers that exhibit Pt(I) or Pd(I) in the main chain. A typical example is the ring-stressed complex Pd2(dmb)22f2 (where X = Cl or Br).38 The latter exists as a binuclear complex in solution but forms a polymer in the solid state (Fig. 16). 

TABLE 4. Emission Data for the Model Compounds and Corresponding Coordination Polymers in the Solid State at 298 K... 

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