Search results for "Non covalent"

Covalent and non-covalent chemistry of 2D black phosphorus

2021

The post-graphene era is undoubtedly marked by two-dimensional (2D) sheet polymers, such as black phosphorus (BP). This emerging material has a fascinating structure and outstanding electronic properties and has been postulated for a plethora of applications. The need to circumvent the pronounced oxophilicity of P atoms has dominated the research on this material in recent years, with the objective of finding the most effective method to improve its environmental stability. When it comes to chemical functionalization, the few approaches reported so far involve some drawbacks such as low degree of addition and low production ability. This review presents the concepts and strategies of our st…

Properties and Structural Studies of Multi-Wall Carbon Nanotubes-Phosphate Ester Hybrids

2013

Long chain phosphate esters bearing at least one or two aryl groups have been synthesized and used for the preparation of stable multi-walled carbon nanotube (MWCNT) hybrids. The non-covalent interaction ester/MWCNT has been investigated by several techniques (SEM, UV-vis, 31P-NMR, RAMAN). The used phosphate ester derivatives demonstrated the ability to produce an excellent dispersion of MWCNT in CHCl3. The obtained dispersions showed a great stability from one to at least three weeks in the range of concentration considered. Thermal analysis showed an increase in the decomposition temperature for the hybrids with respect to pristine MWCNT.

Weighting non-covalent forces in the molecular recognition of C60. Relevance of concave–convex complementarity

2008

The relative contributions of several weak intermolecular forces to the overall stability of the complexes formed between structurally related receptors and [60]fullerene are compared, revealing a discernible contribution from concave–convex complementarity. Viruela Martin, Pedro Manuel, Pedro.M.Viruela@uv.es ; Viruela Martin, Rafael, Rafael.Viruela@uv.es ; Orti Guillen, Enrique, Enrique.Orti@uv.es

Assembly and encapsulation of coordination tectons driven by hydrogen-bondingand space-filling

2001

[FR] Le composé ¿Fe(LI)3¿2¿Fe(H2O)6¿(ClO4)6 (2), LI = 1,10-phénanthroline-5,6-dione, a été synthétisé et caractérisé. La structure cristalline 2 est définie par un assemblage bidimensionnel non covalent, peu commun, constitué par des tectons chiraux ¿Fe(LI)3¿2+, assemblés par des cations ¿Fe(H2O)6¿2+ encapsulés dans des cages. Ces cages sont formées par 12 liaisons hydrogène établies entre les molécules d¿eau coordinées et les groupes dione appartenant à six molecules chirales ¿Fe(LI)3¿2+ ¿, ¿ alternées.

Collision induced fragmentations of multiply charged sodium bis(2-ethylhexyl)-sulfosuccinate aggregates in gas phase: neutral loss versus charge sepa…

2016

Abstract Stability and fragmentation patterns of multicharged aggregates of sodium bis(2-ethylhexyl)-sulfosuccinate (NaAOT) in gas phase have been investigated by ion mobility mass spectrometry (IM-MS) and tandem mass spectrometry (MS-MS). Positively doubly charged NaAOT aggregates show at low collision energy a preference for the loss of NaAOT molecules, whereas fragmentation through charge separation process is favored at higher collision energy. By increasing the charge state of the aggregates, the fragmentation through charge separation tends to predominate especially at low aggregation number and only charge separation fragmentation is observed for positively quadruply charged species.…

Studi di macroaggregati a singola carica in fase gassosa: AOT in presenza di ioni sodio e itterbio

2008

IBRIDI FORMATI DA NANOTUBI DI CARBONIO A PARETE MULTIPLA E ESTERI FOSFORICI: PROPRIETA’ E STUDI STRUTTURALI

2012

Nel corso degli ultimi anni i nanotubi di carbonio in virtù delle loro proprietà fisiche, chimiche e meccaniche sono diventati tra i più promettenti materiali per la realizzazione di congegni a livello nanometrico. I CNT trovano numerose applicazioni nel campo, della nanoelettronica, nella costruzione di materiali ad elevata conducibilità elettrica ed elevata resistenza meccanica,2 e vengono, anche, impiegati come agenti di rinforzo dispersi in una matrice polimerica.3 Problema principale di questi materiali è che essi risultano scarsamente solubili in ambiente acquoso e in solventi organici, a causa delle forti forze attrattive di van der Waals che esistono tra le superfici dei CNT, che li…

Interazioni non covalenti tra esteri fosforici e nanotubi di carbonio a parete multipla

2010

Fin dal 1991, quando Iijima li osservò per la prima volta, i nanotubi di carbonio (CNT) sono diventati oggetto d'interesse scientifico, in virtù delle loro proprietà fisiche, chimiche e meccaniche. Un impiego molto interessante riguarda l'aumento di stabilità di matrici polimeriche. I nanocompositi polimerici, in cui sono presenti percentuali molto basse di CNT (2.5%), presentano enormi miglioramenti nelle caratteristiche termomeccaniche, nella resistenza al calore e nella conduttività elettrica. C'è, però, un impedimento fondamentale a tutte le applicazioni che riguarda l'insolubilità intrinseca dei CNT nei solventi. La funzionalizzazione sia essa covalente che non è un espediente per ovvi…