Crown ethers substitution

Accordingly, iV-phenyl-substituted isothiazolium salts bearing a benzo crown ether substituent were employed in this synthetic protocol and led to the synthesis of various crown ether-substituted 6aA4-thia-l,6-diazapentalenes 201... 

Pond SJK, Tsutsumi O, Rumi M et al (2004) Metal-ion sensing lluorophores with large two-photon absorption cross sections aza-crown ether substituted donor-acceptor-donor distyryl benzenes. J Am Chem Soc 126 9291-9306... 

Crown-ether-substituted ligands were first investigated by Okano et al. (structure 8), who prepared arylphosphanes with these groups (48). 

Griiner, B., Plesek, J., Baca, J. et al. 2002. Crown ether substituted cobalt bis(dicarbollide) ions as selective extraction agents for removal of Cs + and Sr2 + from nuclear waste. New J. Chem. 26 (7) 867-875. 

Fig. 10 Proposed structure for the cation-induced dimer of crown ether substituted metalloph-thalocyanines. Solid circles indicate cations such as K+ and Ca2 1 (reproduced from Kobayashi N, Lever ABP (1987) J Am Chem Soc 109 7433 with permission from the American Chemical Society)...

Cation-induced supramolecular formation of crown ether substituted phthalocya-nines can also be regarded as due to host-guest interactions. Fig. 10 shows the proposed structure for the K+- and Ca2+-induced dimer of metallophthalocya-nines fused with four 15-crown-5 units, which serves as a typical example. The formation of these cofacial dimers has been found to go through a two-step three-stage process. The earlier works have been briefly reviewed [93, 94], Recently, Jiang et al. have prepared a series of copper(II) phthalocyanines fused with one to four 15-crown-5 unit(s) [CuPc(15-C-5) ] (n = 1 1) by heating a solution of the double-decker complexes Eu(Pc)[Pc(15-C-5) ] (n = 1-4) with Cu(OAc)2 in... 

C.F. Vannostrum, S.J. Picken, A.J. Schouten, R.J.M. Nolle, Synthesis and Supramolecular Chemistry of Novel Liquid-Crystalline Crown Ether-Substituted Phthalocyanines Toward Molecular Wires and Molecular lonelectronics , J. Am. Chem. Soc., 117, 9957 (1995)... 

The crown ether-substituted aryl-Grignard 2-bromomagnesio-l,3-xylyl-15-crown-4 (40) crystallized as a solvent-free complex from its THF solu-... 

Cation-induced or solvent-induced supermolecular phthalocyanine formation - crown-ether substituted phthalocyanines, N. Kobayashi and A. B. P. Lever, J. Am. Chem. Soc., 1987, 109, 7433. 

Crown ether-substituted phthalocyanines of the type (72) have been studied by several research groups. These compounds exhibit very interesting complexation properties. 

Roisin, P. Wright. J.D. Nolte. R.J.M. Sielcken. O.E. Thorpe, S.C. Gas-sensing properties of semiconducting-films of crown-ether-substituted phthalocyanines. J. Mater. Chem. 1992. 2 (1). 131-137. 

A crown ether substituted phthalocyanin was adsorbed on HOPG. presenting several orientations. The molecules can be manipulated with the STM tip to adopt different orientations on the substrate." The STM images of an aromatic cryptand adsorbed on HOPG show the formation of chains of molecular nanoclusters and areas with a 2D arrangement of the molecules. 

Scheib, S., and P. Bauerle. 1999. Synthesis and characterization of oligo- and crown ether-substituted polythiophenenes—A comparative study. / Mater Chem 9 2139-2150. 

Other Routes. Substituted PPV derivatives have also been prepared by several other routes. In cases where the resulting polymers are soluble, these methods are often successful in preparing high molecular weight material. The Gilch route has been used to prepare phenyl and crown ether substituted polymers... 

Intermolecular interactions between Pc moieties and electron-donor or electron-acceptor units other than Pcs have also been exploited in order to promote the organization in Pc-based systems. One of the examples has been reported by Amabilino, Rowan, and Nolte, who prepared a TTF-crown ether-substituted Pc 8 (Figure 6a), which was able to self-organize in solution mainly because of intermolecular interactions between the TTF and the Pc moieties as inferred from UV-vis studies. TEM analysis of the gel... 

Figure 6 Tetrathiafulvalene (TTF)-crown ether-substituted Pc 8. Transmission electron microscopy showing the formation of chirai helical fibers of P and M helicity. (Reproduced from Ref. 22. Royal Society of Chemistry, 2005.)...

Crown-ether substitution to introduce selective cation-binding properties was attempted by electro-... 

As has been observed for crown ether-substituted polythiophenes [260, 261], the aza crown ether-substituted polymer poly(18) exhibited a cation-selective electrochemical response with an an-... 

In addition to PPy and PTh derivatives, numerous reports have focused on the synthesis and the properties of electroactive polymer films electrogenerated from the oxidation of crown ether-substituted benzenes [273-286] and naphthalenes [17, 287-293]. Among them, poly(dibenzo-crown ether)s and, especially, poly(dibenzo-18-crown-6) have been the most extensively studied, owing to their remarkable structural, electrochemical, and complexing properties [278-280]. Furthermore, their affinity for a large variety of cations, including heavy metal and precious metal cations, was greatly improved when they were previously undoped [281-286]. 

Besides sulfo groups, a lot of other hydrophilic moieties were tried for modification of phosphine ligands. In some cases the modification pursued several goals, e.g. to impart not only hydrophilicity but also phase-transfer properties, as in the case of polyether- or crown ether-substituted phosphines [16]. 

---