Search results for "supramolecular"
showing 10 items of 830 documents
Synthesis and Supramolecular Association of Immobilized NCN-Pincer Platinum(II) Complexes on Hyperbranched Polyglycerol Supports
2004
Pertosylation of hyperbranched polyglycerol (M(n)=2000; M(w)/M(n)=1.3) followed by partial displacement of the tosyl groups with carboxylic acid functionalized NCN-pincer platinum(II) complexes [PtI-2,6-(NMe(2)CH(2))(2)C(6)H(2)-4-COOH], resulted in covalent attachment of the NCN-pincer complexes to the polyglycerol. These functionalized hyperbranched macromolecules have been characterized by (1)H, (13)C, and (195)Pt NMR, UV-visible, and IR spectroscopy. The presence of Pt and I atoms renders them directly visible by transmission electron microscopy (TEM) without staining procedures, which offers images of associated hyperbranched macromolecules. TEM micrographs show disk-shaped structures w…
Evidence for the formation of covalent bonds between macromolecules in the domain of the wall of Candida albicans mycelial cells
1989
An O-glycosylated mannoprotein, after its incorporation into the wall, showed an increase in its molecular weight, due at least to its association with N-glycosidic sugar chain(s). This was shown by rendering the material soluble after partial degradation of the wall structure. At present it is unknown whether this phenomenon is due to an additional transglycosylation process or whether the partial degradation of the wall solubilizes a supramolecular structure formed between the original O-glycosylated protein which becomes linked either directly or indirectly through a protein to the N-sugar chain(s).
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…
Exploiting multivalent nanoparticles for the supramolecular functionalization of graphene with a nonplanar recognition motif.
2013
The supramolecular modification of planar graphene with the geometri- cally mismatched, curved 9,10-di(1,3-dithiole-2-ylidene)-9,10-dihydroanthracene (exTTF) molecule is demonstrated. The exTTF-graphene interaction is governed by p-p and CH-p interactions, with a negligible contribution from charge transfer. We amplified these weak forces through multivalent gold nanoparticles. Our re- sults show that planarity is not a prerequisite for recognition motifs for graphene.
DEEP EUTECTIC SOLVENTS E LIQUIDI IONICI: SOLVENTI PER LO SVILUPPO DI PROCESSI ECO-COMPATIBILI
2020
L’obiettivo di questi tre anni di Dottorato è stato lo studio e l’utilizzo nuovi solventi di reazione in grado di sostituire i solventi organici classici. In particolare sono stati studiati i Deep Eutectic Solvent (DES) e le miscele di Liquidi Ionici (IL). I DES sono stati utilizzati come solventi per lo studio di reazioni organiche, usate per la formazione di nuovi legami C-C. Nello specifico sono state studiate la reazione di Diels-Alder, e diverse reazioni di coupling C-C catalizzate da Pd. In seguito, i DES sono stati utilizzati per la formazione di nuovi gel supramolecolari, chiamati eutectogel. Questi gel sono stati formati usando come gelator amminoacidi naturali, consentendo quindi …
Use of green alternative solvents in dispersive liquid‐liquid microextraction: A review
2021
Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the Analytical Chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low density solvents, such as alkanols, switchable hydrophobicity solvent…
Cluster Preface: Heterogeneous Catalysis
2016
International audience; Jean-Cyrille Hierso is full professor of Chemistry since 2009, heading the group of ‘Organometallic Chemistry and Catalysis’ at the Institute of Molecular Chemistry at the University of Bourgogne Franche-Comté (UBFC). He has interest in the fields of organometallic chemistry, ligand design, homo- and heterogeneous catalysis, chemical physics, and material sciences. In 2011 he was awarded the National Prize for Coordination Chemistry from the French Chemical Society (SCF), and at the end of 2012 he was elected a junior Member of the French Professors Academy ‘Institut Universitaire de France’ (IUF).Yasuhiro Uozumi is a full professor at the Institute for Molecular Sci…
Evaluation of Antiradical Activity and Reducing Capacity of Synthesised Bispyridinium Dibromides Obtained by Quaternisation of 4-Pyridyl-1,4-dihydrop…
2015
New bispyridinium dibromides based on the 1,4-dihydropyridine (1,4-DHP) cycle were synthesised in the reaction between 4-pyridyl-1,4-DHP derivatives and propargyl bromide. It has been shown that variation of the substituent position on the pyridine as well as small changes in the electronic nature of the 1,4-DHP cycle as a result of the substituent nature at the 3 and 5 positions do not affect the course of the reaction and in all cases the corresponding bispyridinium dibromides 4a–e were formed. The antiradical activity, using 1,1-diphenyl-2-picrylhydrazine as a free radical scavenger, and the reducing capacity using phosphomolybdenum complexes have been evaluated for the newly synthesise…
Halogen Bonding beyond Crystals in Materials Science
2019
Halogen bonding has recently gained well deserved attention in present-day research for its importance in many fields of supramolecular science and crystal engineering. Although generally overlooked in comprehensive studies in the past, halogen bonding has become an important tool also in the field of materials science. An increased number of scientific reports are published every year where halogen bonding is exploited in soft materials rather than in crystal engineering. Here, we focus on a description of the most exciting contemporary developments in the field of halogen-bonded functional soft materials, assembled using the guiding principles of crystal engineering. We give a particular …
Carbonyl Hypoiodites as Extremely Strong Halogen Bond Donors
2021
Abstract Neutral halogen‐bonded O−I−N complexes were prepared from in situ formed carbonyl hypoiodites and aromatic organic bases. The carbonyl hypoiodites have a strongly polarized iodine atom with larger σ‐holes than any known uncharged halogen bond donor. Modulating the Lewis basicity of the selected pyridine derivatives and carboxylates leads to halogen‐bonded complexes where the classical O−I⋅⋅⋅N halogen bond transforms more into a halogen‐bonded COO−⋅⋅⋅I−N+ ion‐pair (salt) with an asymmetric O−I−N moiety. X‐ray analyses, NMR studies, and calculations reveal the halogen bonding geometries of the carbonyl hypoiodite‐based O−I−N complexes, confirming that in the solid‐state the iodine at…