Search results for "guest"

Aggregati supramolecolari di tensioattivi in fase gassosa: formazione e solubilizzazione di aminoacidi

Cyclodextrins as a Key Piece in Nanostructured Materials: Quantitation and Remediation of Pollutants

2021

Separation and pre-concentration of trace pollutants from their matrix by reversible formation of inclusion complexes has turned into a widely studied field, especially for the benefits provided to different areas. Cyclodextrins are non-toxic oligosaccharides that are well known for their host–guest chemistry, low prices, and negligible environmental impact. Therefore, they have been widely used as chiral selectors and delivery systems in the pharmaceutical and food industry over time. However, their use for extraction purposes is hampered by their high solubility in water. This difficulty is being overcome with a variety of investigations in materials science. The setting-up of novel solid…

Towards the fluorogenic detection of peroxide explosives through host-guest chemistry

2018

[EN] Two dansyl-modified beta-cyclodextrin derivatives (1 and 2) have been synthesized as host-guest sensory systems for the direct fluorescent detection of the peroxide explosives diacetone diperoxide (DADP) and triacetone triperoxide (TATP) in aqueous media. The sensing is based on the displacement of the dansyl moiety from the cavity of the cyclodextrin by the peroxide guest resulting in a decrease of the intensity of the fluorescence of the dye. Both systems showed similar fluorescent responses and were more sensitive towards TATP than DADP.

Carbon Nanotubes Conjugated with Triazole-Based Tetrathiafulvalene-Type Receptors for C60 Recognition

2019

Fullerene receptors prepared by a twofold CuI -catalyzed azide-alkyne cycloaddition (CuAAC) reaction with -extended tetrathiafulvalene (exTTF) have been covalently linked to singlewalled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The nanoconjugates obtained were characterized by several analytical, spectroscopic and microscopic techniques (TEM, FTIR, Raman, TGA and XPS), and evaluated as C60 receptors by UV-Vis spectroscopy. The complexation between the exTTF-triazole receptor in the free state and C60 was also studied by UV-Vis and 1 H NMR titrations, and compared with analogous triazole-based tweezer-type receptors containing the electron-acceptor 11,11,12,12-t…

Supramolecular functionalization and concomitant enhancement in properties of Au25 clusters

2014

We present a versatile approach for tuning the surface functionality of an atomically precise 25 atom gold cluster using specific host-guest interactions between ?-cyclodextrin (CD) and the ligand anchored on the cluster. The supramolecular interaction between the Au25 cluster protected by 4-(t-butyl)benzyl mercaptan, labeled Au25SBB18, and CD yielding Au25SBB18�?�CDn (n = 1, 2, 3, and 4) has been probed experimentally using various spectroscopic techniques and was further analyzed by density functional theory calculations and molecular modeling. The viability of our method in modifying the properties of differently functionalized Au25 clusters is demonstrated. Besides modifying their optoe…

Crystallography of encapsulated molecules.

2017

The crystallography of supramolecular host–guest complexes is reviewed and discussed as a part of small molecule crystallography. In these complexes, the host binds the guests through weak supramolecular interactions, such as hydrogen and halogen bonding, cation–π, anion–π, C–H–π, π–π, C–H–anion interactions and the hydrophobic effect. As the guest often shows severe disorder, large thermal motion and low occupancies, the reliable crystallographic determination of the guest can be very demanding. The analysis of host–guest interactions using tools such as Hirshfeld and cavity volume surface analysis will help to look closely at the most important host–guest interactions. The jewel in the cr…

Supramolecular Heteropolyoxopalladate {Pd15} Cluster Host Encapsulating a {Pd2} Dinuclear Guest: [PdII2-{H16-nPdII15O10(PO4)10}]n-

2011

Ahigh-nuclearity polyoxopalladate compound, [PdII2⊂{H7PdII15O10(PO4)10}]9 {PdII17}, comprising a {Pd15} host occupied by a {Pd2} guest and the parent pristine “empty” [H7PdII15O10(PVO4)10]13 {Pd15} cluster have both been prepared and characterized by single-crystal X-ray crystallography, 31P NMR, CSI-MS, and XPS. The encapsulated {Pd2} has a short PdII PdII distance within the {Pd15} host. Solution studies indicate that the empty host and filled guest complex are in equilibrium with each other, and UV titrations revealed a binding constant of ca. 103 for the guest PdII ions, with a binding stoichiometry of almost 2.

Hydrogen-Bonded Analogues of Cavitands

2000

Self-Assembled Hydrogen-Bonded Dimeric Capsules with High Kinetic Stability

2000

Capturing Hydrophobic Trifluoroiodomethane in Water into an M 4 L 6 Cage

2016

Synthetically important trifluoroiodomethane (CF3I) was trapped in water by using a metal–organic supramolecular anionic cage. Under ambient conditions, nearly 1:1 encapsulation of the hydrophobic, gaseous CF3I substrate with the cage was observed, and its binding constant was calculated by relative comparison with benzene encapsulation.