Carbon-13 NMR chemical shifts. A single rule to determine the conformation of calix[4]arenes

Jaime, Carlos; Mendoza, Javier de; Prados, Pilar; Nieto, Pedro M.; Sánchez, C.

doi:10.1021/jo00010a036

Cited by 599 publications

(364 citation statements)

References 1 publication

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“…The same reasoning can be applied to the corresponding carbon atoms (C1 and C2), one of which is shifted upfield by 1.1 ppm in A 4 bL 4 compared with A 6 L 6 . 13 C{ 1 H} NMR spectra in both CDCl 3 and CD 3 CN confirm the fast exchange hypothesis (see Figure S1 in the Supporting Information; see also the footnote on the first page of this article) since δ(C 13 ) ϭ 30.95 ppm points to a syn orientation of adjacent phenol rings, [27] thus excluding the hypothetical 1,3,5-alternate conformation in which adjacent rings are in an anti conformation. Only four signals are observed for the aromatic carbon atoms, indicating the equivalence of the six aromatic rings on the NMR time scale, and an average hexagonal (D 6h ) symmetry for the calixarene core.…”

Section: Resultssupporting

confidence: 62%

Tuning the Stoichiometry of Lanthanide Complexes with Calixarenes: Bimetallic Complexes with a Calix[6]arene Bearing Ether‐Amide Pendant Arms

et al. 2004

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A de-tert-butylated calix [6]arene (A 6 L 6 ) fitted with six etheramide pendant arms was synthesized and characterized in solution. NMR spectroscopic data point to the six phenoxide units adopting an average D 6h conformation on the NMR time scale. According to MM3 molecular mechanics, and MOPAC quantum mechanical calculations, A 6 L 6 is a ditopic ligand featuring two nonadentate coordination sites, each built from three pendant arms, and extending in opposite directions with one above, and the other under the main ring. A 6 L 6 reacts with Ln III ions (Ln = La, Eu) in acetonitrile to successively form 1:1 and 2:1 complexes. The isolated Eu III 2:1 complex is luminescent (quantum yield: 2.5% in acetonitrile, upon ligand excitation). In the solid state, the luminescence decay is bi-exponential, with lifetimes equal to 1.66 and 0.46 ms (upon direct metal excitation), pointing to the presence of two differently coordinated metal ions, one with essentially

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Section: Resultssupporting

confidence: 62%

Tuning the Stoichiometry of Lanthanide Complexes with Calixarenes: Bimetallic Complexes with a Calix[6]arene Bearing Ether‐Amide Pendant Arms

et al. 2004

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“…48 The structures of the new compounds were fully confirmed by their FT-IR, 1 H-NMR, 13 C-NMR, DEPT, and mass spectra (ESI-MS).…”

Section: Resultsmentioning

confidence: 85%

Synthesis of a Series of Novel Tetra-tert-butylcalix[4]arene Linked to 1,2,4-Triazole and 1,3,4-Oxadiazole Derivatives

Dilmaghani¹,

Ghezelbash²

2016

ACSi

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A series of tetra-tert-butylcalix[4]arene linked to 1,2,4-triazole-5-thiones and 1,3,4-oxadiazole-5-thiones derivatives at lower rim were synthesized by the reaction of 1,2,4-triazole-5-thione and 1,3,4-oxadiazole-5-thione with 5,11,17,23-tetra-tert-butyl-25,27-bis(3-bromopropoxy)-26,28-dihydroxycalix[4]arene (2). The synthesized compounds were characterized by FT-IR, 1 H NMR, 13 C NMR spectral data, elemental analysis and ESI-MS.

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“…This result suggests that 1 exists in the cone conformation. 25,26 Similarly, the methylene hydrogens splitting pattern indicated that compounds 2, 3 and 4 also adopted the cone conformation. As shown in Figure 2, the UV-Vis spectrum of compound 1 containing pyrene and perylene shows a broad absorption band corresponding to a superposition of two the spectra of compound 2 having a pyrene moiety and compound 3 having a perylene moiety.…”

Section: Resultsmentioning

confidence: 98%

Effective fluorescent sensing of Na+ ion by calix[4]arene bearing pyrene and perylene based on energy transfer

Nishimura¹,

Takemura²,

Arai³

2007

Arkivoc

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A new calix [4]arene having pyrene and perylene moieties has been synthesized as a Na + detectable fluorescent ionophore. When excited at the pyrene moiety (342 nm) of the ionophore, a strong fluorescence emission of the perylene moiety (535 nm) was observed due to energy transfer from the pyrene to perylene. By addition of Na + at a low concentration in the range of 2.5-10 µM, the fluorescence was remarkably quenched. In contrast to the fluorescent behavior by the ionophore having pyrene and perylene moieties, the excimer emission of a calix[4]arene derivative having two pyrene moieties decreased by the addition of Na + with a concentration in the range of 50-200 µM.

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Carbon-13 NMR chemical shifts. A single rule to determine the conformation of calix[4]arenes

Cited by 599 publications

References 1 publication

Tuning the Stoichiometry of Lanthanide Complexes with Calixarenes: Bimetallic Complexes with a Calix[6]arene Bearing Ether‐Amide Pendant Arms

Tuning the Stoichiometry of Lanthanide Complexes with Calixarenes: Bimetallic Complexes with a Calix[6]arene Bearing Ether‐Amide Pendant Arms

Synthesis of a Series of Novel Tetra-tert-butylcalix[4]arene Linked to 1,2,4-Triazole and 1,3,4-Oxadiazole Derivatives

Effective fluorescent sensing of Na+ ion by calix[4]arene bearing pyrene and perylene based on energy transfer

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