14607-11-5Relevant articles and documents
Specific sensing between inositol epimers by a bis(boronate)
Gray Jr., Charles W.,Johnson Jr., Leland L.,Walker, Brian T.,Sleevi, Mark C.,Campbell, A. Stewart,Plourde, Robert,Houston, Todd A.
, p. 5416 - 5418 (2005)
Bis(boronates) that utilize internal photoinduced electron transfer (PET) quenching mechanisms can specifically signal the binding of chiro-inositol without responding to its epimer, myo-inositol.
Hydrogen-bonded complexes of aromatic crown ethers with (9-anthracenyl)methylammonium derivatives. Supramolecular photochemistry and photophysics. PH-controllable supramolecular switching
Ashton, Peter R.,Ballardini, Roberto,Balzani, Vincenzo,Gómez-López, Marcos,Lawrence, Simon E.,Victoria Martínez-Díaz,Montalti, Marco,Piersanti, Arianna,Prodi, Luca,Fraser Stoddart,Williams, David J.
, p. 10641 - 10651 (1997)
The (9-anthracenyl)methylammonium and (9-anthracenyl)benzylammonium tetrakis(hexafluorophosphate) salts give hydrogen-bonded complexes in CH2Cl2 with aromatic crown ethers containing dibenzo (DB) or dinaphtho (DN) units. The association constants vary from 3 x 103 to 1 x 106 M-1 in CH2Cl2, depending on the specific ammonium cation and crown ether involved. In a number of cases, pseudorotaxane-like geometries for the complexes are demonstrated by (a) 1H NMR spectroscopy in solution, (b) X-ray crystallography in the solid state, and (c) mass spectrometry in the gas phase. The results obtained by absorption, emission, and excitation spectroscopy and excited lifetimes show that, as a consequence of the hydrogen bond driven recognition process, the anthracene chromophoric unit interacts with the aromatic units of the crown ethers. In the complexes involving the DB18C6, DB24C8, and DB30C10 macrocycles, the interaction leads to the complete quenching of the fluorescence of the dialkoxybenzene moieties and parallels sensitization of the anthracene fluorescence. In the complexes of 1/5-DN38C10, both the crown and the anthracene fluorescence are completely quenched, most likely by an energy-transfer cascade involving the triplet state of the dialkoxynaphthalene moiety. In the complexes of 2/3-DN30C10, the interaction between the anthracene moiety and the naphthalene rings of the crown ether is relatively strong, as indicated by the perturbation of the absorption bands, the disappearance of the fluorescence bands of the naphthalene- and anthracene-type chromophoric units, and the appearance of a new, broad fluorescence band. The complexes can also be formed by addition of CF3COOH or CF3SO3H to CH2Cl2 solutions containing crown ether and amine. The association process between DB24C8 and (9-anthracenyl)benzylammonium salt can be reversed quantitatively upon addition of a suitable base and the complex can be formed again after treatment with acid.
Molecular interactions, proton exchange, and photoinduced processes prompted by an inclusion process and a [2]pseudorotaxane formation
Mandal, Amal Kumar,Suresh, Moorthy,Kesharwani, Manoj K.,Gangopadhyay, Monalisa,Agrawal, Manoj,Boricha, Vinod P.,Ganguly, Bishwajit,Das, Amitava
, p. 9004 - 9012 (2013/10/08)
Appropriate design of the host and guest components allows formation of a novel [2]pseudorotaxane complex with an interrupted photoinduced electron transfer (PET)-coupled fluorescence resonance energy transfer (FRET) response. This is the first example of an inclusion complex with NO6-based azacrown ether as the host unit (H). Different guest molecules (G1, G2, G3, and G4) with varying stopper size are used for the studies. Unlike G1, G2, and G3, G4 with a relatively bulkier stopper fails to form a [2]pseudorotaxane complex. Isothermal titration microcalorimetry measurements reveal a systematic increase in the association constant for H·G1, H·G2, and H·G3 with a change in the stopper size. Thermodynamic data suggest that the formation of H·G1/H·G2/H·G3 is exclusively driven by a large positive entropic gain (TΔS = 19.69/26.80/21.81 kJ·mol-1), while the enthalpy change is slightly negative for H·G1/H·G3 (-2.61/-1.97 kJ·mol-1) and slightly positive for H·G2 (ΔH = 5.98 kJ·mol-1). For these three inclusion complexes, an interrupted PET-coupled FRET response is observed with varying efficiency, which is attributed to the subtle differences in acidity of the NH2+ unit of the guest molecules and thus the proton exchange ability between the host and respective guest. This is substantiated by the results of the computational studies.
