Calix[3]carbazole: One-Step Synthesis and Host–Guest Binding

Abstract

The one-step synthetic strategy for the preparation of the hitherto unknown calix[3]carbazole from readily available starting materials is described. Calix[3]carbazole is obtained in 20% yield, and it could selectively bind the N(C2H5)4(+) cation (tetraethylammonium, TEA) via cation-π interactions. The experimental and modeling results indicate that calix[3]carbazole possesses a larger π-cavity as well as a better chromophoric property than the traditional phenol-based macrocycles, and thus is capable of binding to and optically responding to the relatively large guest TEA.

Calix[n]phenothiazines: Optoelectronic and Structural Properties and Host–Guest Chemistry

“…37,41 The resulting binding constants were K ¼ 50 AE 3, 91 AE 4, and 128 AE 9 M À1 for the complex formation between [3]CPT-Hex and 4, 5, and 6, respectively. For the ammonium cations 5 and 6, the binding constants are larger than that reported for calix [3]carbazole 13 with the tetraethylammonium cation (up to 66.8 M À1 ).…”

“…35 For N-arylphenothiazines, emissions around or above 500 nm and such large Stokes shifts were only observed with electron-withdrawing substituents at the aryl group (CN or CF 3 ), 35 Finally, we performed host-guest studies of [3]CPT-Hex with different guests. For comparison with the recently reported calix [3]carbazole, 13 we chose the imidazole derivative 4 as a neutral guest, which shows high binding constants (up to 10 4 M À1 ) towards pillar [5]arenes, 36 as well as tetraalkylammonium cations, namely 5 and 6 (Figure 6a). NMR titration experiments 37 of [3]CPT-Hex solutions with these guest molecules showed a shift in the phenothiazine 1 H NMR resonances with increasing guest concentrations (see Figure 6b, spectra for other titrations can be found in Supporting Information).…”

“…Examples are calix [4]pyrroles, 4 calix[n]furanes (n ¼ 5-8), 5,6 calix [4]thiophenes, 7 calix[n]triazoles (n ¼ 4-6), 8 calix[n] imidazolium salts (n ¼ 4, 5), 9 calix[n]indoles (n ¼ 3, 4), [10][11][12] and the recently reported calix[n]carbazoles (n ¼ 3, 4). 13,14 Phenothiazine has long been of interest to chemists 15,16 due to its pharmacological and biological activity [15][16][17][18] and its use in dye chemistry, [19][20][21] among others. Phenothiazines are fluorescent and feature a reversible oxidation process, which makes them attractive for applications in organic electronics [22][23][24] and in batteries.…”

Supramolecular Recognition of Three Way Junction DNA by a Cationic Calix[3]carbazole

“…Figure showed that in the absence of DNA, 2 exhibited only two peaks in the region of 6.9–7.7 ppm, which were assigned to H 1(8) and H 4(5) , respectively. The symmetric and relatively simple 1 H NMR profile indicated that the unbound/free 2 adopted either i) a flatten partial cone (or saddle) conformation, or ii) a rapidly inverted cone conformation on the NMR time scale . Due to the electronic repulsion of the oxygen atoms of 2,7‐dimethoxyl groups of neighbors’ carbazolyl moieties of 2 , the former case would be more possible.…”

Engineering 1,3-Alternate Calixcarbazole for Recognition and Sensing of Bisphenol F in Water

“…We recently reported a novel series of non-phenol-based macrocycles: calixcarbazoles . The cavity of calix[3]­carbazole, the smallest one among those carbazolyl macrocycles, is already larger than that of calix[4]­arene.…”