Calix -pyrrole

Di-rerr-butylsodium pyrrolate serves as a source of the complexes of lanthanides [93CB2657 95JOM(495)C12]. Thus, with cyclooctadienyl chlorides of samarium, thulium, and lutetium, it affords species 89 [96JOM(507)287]. The N-coordinated samarium(II) calix-pyrrole complex is known [99AG(E)1432]. 

Since analogous macrocyclic arrays with pyrrole rings have been termed calix[ ]pyrroles (cf. Gale PA, Sessler JL, Krai V, Lynch V (1996) J Am Chem Soc 118 5140) it would be appropriate to rename these thiophene-crowns as calix[n] thiophenes... 

Figure 117 (Et8-calix-pyrrole)Sm2(THF)4 (Et-groups are omitted for clarity)...

Kaledkowski, A. and Trochimczuk, A. W. (2006). Chelating resin containing hybrid calix-pyrroles New sorbent for noble metal cations. React. Funct Polym. 66(9), 957-966. 

Calix[ ]arenes and calix[ ]pyrroles can dramatically change their conformation. Vase-shaped calix[ ]arenes have two rotation modes of the phenolic units the ojygen-through-the-annulus rotation and the para-substituent-through-the-annulus rotation (Figure 4.2). ... 

The Ciamician-Dennstedt reaction is currently the only way to date to make calix[4]pyridine 20.(Scheme 8.3.6) Four sequential treatments of calix[4]pyrrole 19 with sodium trichloroacetate results in all four possible geometric isomers of 20 (all four... 

There is a case where the resnlts of the electrode and chemical oxidation coincide (see Scheme 2.20). Calix[8]pyrrole was prepared from 3,3, 4,4 -tetraethyl-2,2 -bipyrrole during oxidative electrolysis in dichloromethane nsing platinum anode, tetrabutylammonium hydrogen sulfate as the... 

Calix[4]pyrroles offer an alternative receptor site for the recognition of anions. Miyaji et al. [400] prepared a series of calixpyrrole-anthracene receptors that possess conjugated (73) and unconjugated bond pathways of different lengths (74 and 75). The stability constants (103—105 M-1 determined by NMR titration) for the anion complexes of each member of the series follows the trend... 

While interesting neutral alternatives to the unsaturated expanded porphyrin derivatives, calix[n] pyrroles (n = 4, 5, 6, 8) are relatively limited in their scope for anion binding because of the constraints of the cavity size. Nevertheless pyrroles linked by an sp3 hybridised carbon atom are of considerable interest because of their resemblance to the anti-cancer agents the prodigiosins (Section 4.2.4), moreover pyrrole anion-receptor chemistry is synthetically versatile and hence a range of acyclic pyrroles and hybrid amidopyrroles such as 4.50-4.52 have been developed, particularly by the groups of... 

A more recent development has been the synthesis of bisamidopyrrolylmethane based anion receptor systems (Figure 19).15 These receptors might be regarded as containing half a calix[4]pyrrole combined with die 2-amido appendages in common with the pyrrolic amide cleft. Compounds 19 and 20 were synthesized by reaction of diethyl-5,5 -methylenebis(4-ethyl-3-methyl-2-pyrrole) carboxylate with aniline or n-butylamine in the presence of trimethylaluminium in dry dichloromethane at 35°C in 40 and 43% respective yields. 

That solvents can have a profound and until now often little understood effect on selectivity and affinity of macrocylic hosts is illustrated with the complexation of halide anions with calix[4]pyrrole (Table 1).[31]... 

TABLE 1. Dependence of complex stabilities of a calix[4]pyrrole with halide anions on solvent ... 

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