Missing-Link Macrocycles: Hybrid Heterocalixarene Analogues Formed from Several Different Building Blocks

Sessler, Jonathan L.; Cho, Won Seob; Lynch, Vincent M.; Král, Vladimír

doi:10.1002/1521-3765(20020301)8:5<1134::aid-chem1134>3.0.co;2-m

Cited by 67 publications

(46 citation statements)

References 24 publications

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“…The synthetic methodology followed here is basically an acid‐catalyzed condensation reaction. Stirring a solution of 1 7 with pentafluorobenzaldehyde in dichloromethane in the presence of trifluoroacetic acid (TFA) followed by oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) resulted in calix[ n ]‐ m ‐benzo[ m ]phyrins ( n =2,3,4; m =4,6,8) in 20 % ( M ‐ 1 ), 10 % ( M ‐ 2 ), and 5 % ( M ‐ 3 ) yield, respectively. All the macrocycles were fully characterized by electronic, FAB‐MS, and NMR spectral studies, and the structure of M ‐ 1 was finally confirmed by single‐crystal X‐ray‐diffraction analysis 8.…”

Section: Methodsmentioning

confidence: 99%

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a Hg^II Chemosensor

Salini

Thomas

Sabarinathan

et al. 2011

Chemistry A European J

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In recent years, solid-state fluorescent materials have received much attention in diverse fields, such as fluorescent biological labels, sensors, and light-emitting diodes.[1] Many conjugated organic luminophores are highly emissive in dilute solutions, however, when fabricated into thin films, they suffer an aggregation-caused quenching (ACQ) effect, which limits their practical applications.[1] To solve this problem, recently, some organic molecules, which show an intense emission in the aggregated state, whereas they exhibit almost no or weak emission in dilute solutions, were reported. This unique phenomenon is widely researched as aggregation-induced emission (AIE) [2] and aggregation-induced enhanced emission (AIEE).[3] However, the potential utility of this phenomenon has not been explored in macrocycles. On the other hand, molecular sensors for Hg II ions have received considerable attention due to the extremely toxic impact exerted by Hg II on our environment. [4] Many efforts have been made to design various chemosensors specific to Hg II ions.[5] The major challenges involved in the creation of Hg II sensors are lack of selectivity and specificity. Calixphyrins, polypyrrolic macrocycles, are known for the coordination chemistry, [6] but reports on metal-ion sensing are very rare. Herein, we wish to report the AIEE characteristic of a calixbenzophyrin-derivative, M-1, and utilize this novel property for probing Hg II ions both in aqueous solution and in the solid state.The syntheses of calixbenzophyrins are outlined in Scheme 1. The synthetic methodology followed here is basically an acid-catalyzed condensation reaction. Stirring a solution of 1 [7] with pentafluorobenzaldehyde in dichloromethane in the presence of trifluoroacetic acid (TFA) followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in calix[n]-m-benzo[m]phyrins (n = 2,3,4; m = 4,6,8) in 20 % (M-1), 10 % (M-2), and 5 % (M-3) yield, respectively. All the macrocycles were fully characterized by electronic, FAB-MS, and NMR spectral studies, and the structure of M-1 was finally confirmed by single-crystal Xray-diffraction analysis.[8] All the derivatives are soluble in common organic solvents, but insoluble in water.A solution of M-1 in dilute acetonitrile shows an absorption band at 434 nm, which arises from the p-p* transition of the dipyrrin moiety.[8] The emission spectrum shows a band at 539 nm. We observed an anomalous behavior in the emission spectrum of M-1 upon addition of various percentages of water (0-90 %), upon which the band at 539 nm is intensified with a bathochromic shift to 550 nm (Figure 1, left). Because water is not a good solvent for M-1, addition of water promotes efficient calixphyrin self-aggregation, which enhances the emission; in other words, M-1 is AIEE active. The trajectory of the intensity change suggests that the molecularly dissolved M-1 starts to congregate at a water fraction of 50 % and the population of the aggregate continues to increase as the water fraction increases fr...

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Section: Methodsmentioning

confidence: 99%

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a Hg^II Chemosensor

Salini

Thomas

Sabarinathan

et al. 2011

Chemistry A European J

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“…6–8 For example, recent quantitative carbon K-edge X-ray absorption spectroscopy (XAS) analyses on the organometallic [An(COT) 2 ] (An = Th, U), “actinocenes” provided the first experimental evidence for extensive φ-orbital interactions in thorocene, and remarkably little in the U analogue, with contrasting trends in orbital mixing. 9 Furthermore, a combination of experimental and QTAIM computational comparisons of [M(L Ar )X] (M = Sm, U, Np; X = Cl, I; L Ar = dianionic arene-bridged trans -calix[2]benzene[2]pyrrole 10 ) showed significant differences (up to 17%) in orbital contributions to M–L bonds between the Ln and An analogues, and that the covalency in the Np–ligand bonding arises from spatial orbital overlap rather than a coincidental energy degeneracy. 4 The work also demonstrated differences between U and Np in their reaction chemistry, such as the stability of the Np II formal oxidation state or the reduction of Np IV to Np III upon complexation.…”

Section: Introductionmentioning

confidence: 99%

Reduction chemistry of neptunium cyclopentadienide complexes: from structure to understanding

et al. 2017

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“…Although extremely low reduction potentials of Th IV/III (‐3.0 V versus NHE) and Th III/II (‐4.9 V) were presumed, several Th III complexes and even one Th II complex have been synthesized and structurally characterized via massive efforts . In addition to commonly used cyclopentadienyl (Cp), cyclooctatetraenyl (COT) and their substituted derivatives, a small‐cavity macrocyclic trans ‐calix[2]pyrrole[2]benzene (H 2 L, Figure ), synthesized by the Sessler's group, has been found suitable for chelating Th IV . Interestingly, the flexibility of H 2 L allows its two binding pockets (BP), bis (arene) (marked as Ar L) and bis (pyrrolide) ( Pl L), to hold the actinide ion.…”

Section: Introductionmentioning

confidence: 74%

A Relativistic DFT Probe of Thorium and Protactinium Complexes Supported by Heterocalix[4]arene and Redox Properties of Early‐Middle Actinides

Bao

et al. 2018

ChemistrySelect

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Thorium and protactinium complexes of trans‐calix[2]benzene[2]pyrrolide (H2L) have been examined using a relativistic density functional theory, where the metal center has +IV and +III oxidation states and is saturated by a borohydride donor. Good agreement in geometry parameters has been achieved for the thorium(VI) complex compared with its experimentally obtained analogue. Three types of conformers, labeled as (ArL)(Anm)(2HB), (ArL)(Anm)(3HB) and (PlL)(Anm)(3HB) (An=Th and Pa, m=VI and III), are energetically favored for each complex. The first and last configurations are found to be the most stable for tri‐ and tetravalent complexes, respectively. Intriguing δ(An−Ar) bonding(s) are revealed for trivalent complexes (ArL)(AnIII)(2HB); and (PlL)(PaIV)(3HB) has a Pa(5f)‐dominated HOMO, while (PlL)(ThIV)(3HB) displays a 5f06d07s0 electronic configuration. Exothermic process was calculated for reactions starting from actinide borohydride sources and various macrocyclic ligands. From a thermodynamic perspective, this provides synthetically accessible possibility of these complexes. The mechanism of reducing tetra‐ to trivalent actinide complexes has been proposed. Reduction potentials were calculated to follow the order of Th < Pa < U < Np < Pu, which well reproduces reported results of aquo AnVI/AnIII ions.

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Missing-Link Macrocycles: Hybrid Heterocalixarene Analogues Formed from Several Different Building Blocks

Cited by 67 publications

References 24 publications

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a Hg^II Chemosensor

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a Hg^II Chemosensor

Reduction chemistry of neptunium cyclopentadienide complexes: from structure to understanding

A Relativistic DFT Probe of Thorium and Protactinium Complexes Supported by Heterocalix[4]arene and Redox Properties of Early‐Middle Actinides

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Missing-Link Macrocycles: Hybrid Heterocalixarene Analogues Formed from Several Different Building Blocks

Cited by 67 publications

References 24 publications

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a HgII Chemosensor

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a HgII Chemosensor

Reduction chemistry of neptunium cyclopentadienide complexes: from structure to understanding

A Relativistic DFT Probe of Thorium and Protactinium Complexes Supported by Heterocalix[4]arene and Redox Properties of Early‐Middle Actinides

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Product

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Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a Hg^II Chemosensor

Calix[2]‐m‐benzo[4]phyrin with Aggregation‐Induced Enhanced‐Emission Characteristics: Application as a Hg^II Chemosensor