Macrocyclic ether-containing polymers

The principle of cyclopolymerization has been applied to the synthesis of macrocyclic ether-containing polymers which may simulate the properties of crown ethers. l,2-Bis(ethenyloxy)benzene (a 1,7-diene) and l,2-bis(2-ethenyloxyethoxy)benzene (a 1,13-diene) are typical of the monomers synthesized. Homopolymerization of the 1,7-diene via radical and cationic initiation led to cyclopolymers of different ring sizes homopolymerization of the 1,13-diene led to cyclic polymer only via cationic initiation. Both monomer types were copolymerized with maleic anhydride to yield predominantly alternating copolymers having macro-cyclic ether-containing rings in the polymer backbone. 

The most prominent application of the Ru-arene chemistry has been for the preparation of biaryl ethers in the syntheses of portions of vancomycin,467 ristocetin (Equation (127)),462,468-473 and teicoplanin (see also Section 10.14.1.2).474-476 Additional applications477-479 have included the syntheses of the macrocyclic biaryl ether-containing compounds K-13480,481 and OF4949-III,481,482 several macrocyclic depsipeptides,483,484 and poly(phenylene oxide) polymers.485... 

This approach has been extended to the synthesis of macrocyclic ethers (pseudo-crown ethers) incorporated as part of a macromolecular network (styrene-divinylbenzene copolymer) and results in polymers of high coordinating power for various ions (139). The combination of macrocyclic structures with polymer will allow, in the near future, the development of new catalysts containing specific binding properties together with effective catalytic behavior (348). 

The sorption of Pd(II) and Pt(II) chloride complexes was studied with this macrocycle polymer. The resin had a greater affinity to PdCl4 than for PtCl4. In competitive conditions, the resin was complexing both Pt(II) and Pd(II) from an aqueous solution of 0.50 M potassium chloride, but Pt(II) was complexed to a great extend. Polymers of benzocrown ethers containing 4, 5, 6 and 8 oxygen atoms were also synthesized (Fig. 4) [6]. 

The most popular and commonly used chiral stationary phases (CSPs) are polysaccharides, cyclodextrins, macrocyclic glycopeptide antibiotics, Pirkle types, proteins, ligand exchangers, and crown ether based. The art of the chiral resolution on these CSPs has been discussed in detail in Chapters 2-8, respectively. Apart from these CSPs, the chiral resolutions of some racemic compounds have also been reported on other CSPs containing different chiral molecules and polymers. These other types of CSP are based on the use of chiral molecules such as alkaloids, amides, amines, acids, and synthetic polymers. These CSPs have proved to be very useful for the chiral resolutions due to some specific requirements. Moreover, the chiral resolution can be predicted on the CSPs obtained by the molecular imprinted techniques. The chiral resolution on these miscellaneous CSPs using liquid chromatography is discussed in this chapter. 

Thus, cationic polymerization of oxiranes is of little synthetic value, if the preparation of linear polymers is attempted. The high tendency for cyclization may be employed, however, for preparation of macrocyclic polyethers (crown ethers). Polymerization of ethylene oxide in the presence of suitable cations (e.g., Na+, K+, Rb +, Cs + ) leads to crown ethers of a given ring size in relatively high yields, due to the template effect [105], Thus, with Rb+ or Cs+ cations, cyclic fraction contained exclusively 18-crown-6. 

A number of polymer systems containing macrocyclic ligands, such as the crown ethers, have been prepared. This subject has been reviewed a number of times (Blasius and Janzen, 1982 Gramain, 1982 Sahni and Reedijk, 1984 Smid, 1976, 1981a, 1981b Smid et al., 1979 Takagi and Nakamura, 1986 Yokota, 1989). These reviews report on crown ethers or cryptands attached to solid supports or as part of a polymer system. There have been no separate reviews of polymers containing only aza- or peraza-crown macrocycles. 

Thus, we first discuss thermodynamics, paying attention to features that are important for polymer synthesis (e.g., dependence of equilibrium monomer concentration on polymerization variables) then we describe kinetics and thermodynamics of macrocyclization, trying to combine these two related problems, usually discussed separately. In particular we present the new theory of kinetic enhancement and kinetic reduction in macrocyclics. Thereafter, we describe the polymerization of several groups of monomers, namely cyclic ethers (oxiranes, oxetanes, oxolanes, acetals, and bicyclic compounds) lactones, cyclic sulfides, cyclic amines, lactams, cyclic iminoethers, siloxanes, and cyclic phosphorus-containing compounds, in this order. We attempted to treat the chapters uniformly we discuss practical methods of synthesis of the corresponding polymers (monomer syntheses and polymer properties are added), and conditions of reaching systems state and reasons of deviations. However, for various groups of monomers the quality of the available information differ so much, that this attempt of uniformity can not be fulfilled. 

C.Y. Zhu and R.M. Izatt, Macrocyclic-mediated separation of Eu2+ from trivalent lanthanide cations in a modified thin-sheet-supported liquid membrane system, J. Membr. Sci., 1990, 50, 319 P.R. Brown, J.L. Hallman, L.W. Whaley, D.H. Desai, M.J. Pugia and R.A. Bartsch, Competitive, proton-coupled, alkali metal cation transport across polymer-supported liquid membranes containing s>yn(decyl-dibenzo-16-crown-5-oxyacetic acid) Variation of the alkyl 2-nitrophenyl ether membrane, ibid., 1991, 56, 195. 

An interesting polymer containing macrocyclic rings was formed from pyromellitic tetranitrile by condensation with dianilino ether ... 

The polymer films can also be coordinately reactive in a more reversible way, so that they can be regarded as metal ion partitioning films. Polymeric films containing macrocycles ("crown ethers ) are of this class, and poljnner VIII show in Figure 1 can be used to partition and concentrate, for example T1 from its acetonitrile solutions. 

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