Influence of methyl functional groups on the stability of cubane carbon cage

2016 ◽  
Vol 81 ◽  
pp. 1-6 ◽  
Author(s):  
Konstantin P. Katin ◽  
Vladimir S. Prudkovskiy ◽  
Mikhail M. Maslov
Keyword(s):  
Functional Groups ◽  
Carbon Cage ◽  
The Stability

scholarly journals Functional Groups Required for the Stability of Yeast RNA Triphosphatasein Vitroandin Vivo

2001 ◽  
Vol 276 (32) ◽  
pp. 30514-30520 ◽  
Author(s):  
Martin Bisaillon ◽  
Stewart Shuman
Keyword(s):  
Functional Groups ◽  
The Stability

scholarly journals Concomitant polymorphs of aryl-ether amine via catemer and dimer carboxylic acid supramolecular interactions and their effect on optical properties

2021 ◽  
Author(s):  
Mehboobali Pannipara ◽  
Abdullah G Al-Sehemi
Keyword(s):  
Optical Properties ◽  
Carboxylic Acid ◽  
Crystal Lattice ◽  
Functional Groups ◽  
Molecular Orbital ◽  
Acid Group ◽  
Supramolecular Interactions ◽  
Aryl Ether ◽  
Stability Calculation ◽  
The Stability

Abstract Carboxylic acid supramolecular synthon exhibited dimer or catemer motifs in the crystal lattice depend on the substituent and other functional groups present in the structure. In general, presence of other competing functional groups produced catemer motifs whereas unsubstituted acids showed dimer. In this manuscript, we have synthesized a new aryl ether amine-based Schiff base with carboxylic acid functionality ( 1 ) and demonstrated polymorphic structure via catemer ( 1a ) and dimer ( 1b ) motifs in the solid state. In both the structure, carboxylic acid group adopted different orientation in the crystal lattice. The different H-bonding lead to modulation of optical properties that was further supported highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculation. Further the stability calculation indicates that catemer structure was more stable by 8.54 kcal/mole relative to dimer motifs. In contrast, naphthyl group attached carboxylic acid structure did not show neither dimer nor catemer motifs in the crystal lattice as compared to diethylaminophenyl group, which confirm the presence of other substituent or competing functional groups strongly influence on the motifs of supramolecular interactions.

scholarly journals Synthesis, stability, and reactivity of mesoionic carbene iridium dihydride complexes

2020 ◽  
Author(s):  
Marta Olivares ◽  
Martin Albrecht
Keyword(s):  
Electronic Properties ◽  
Functional Groups ◽  
Pyridine Ring ◽  
Spectroscopic Analysis ◽  
Pka Values ◽  
Trans Effect ◽  
Structural Assignment ◽  
Wide Range ◽  
Hydride Metal ◽  
The Stability

Pyridyl-triazolylidene ligands with variable donor properties were used as tunable ligands at a dihydride iridium(III) center. The straightforward synthesis of this type of ligand allows for an easy incorporation of electron donating substituents in different positions of the pyridine ring or different functional groups such as esters, alkoxy or aliphatic chains on the C4 position of the triazole heterocycle. The stability of these hydride metal systems allowed these complexes to be used as models for studying the influence of the ligand modifications on hydride reactivity. Spectroscopic analysis provided unambiguous structural assignment of the dihydride system. Modulation of the electronic properties of the wingtip substituents did not appreciably alter the reactivity of the hydrides. Reactivity studies using acids with a wide range of pKa values indicated a correlation between hydride reactivity and acidity and showed exclusive reactivity towards the less shielded hydride trans to the carbene carbon rather than the more shielded hydride trans to the pyridine ring, suggesting that the trans effect is more relevant in these reactions than the NMR spectroscopically deduced hydridic character.

Enhancing the stability of metal–organic frameworks in humid air by incorporating water repellent functional groups

2010 ◽  
Vol 46 (33) ◽  
pp. 6120 ◽  
Author(s):  
Tianjiao Wu ◽  
Lingjuan Shen ◽  
Matthew Luebbers ◽  
Chunhua Hu ◽  
Qingmei Chen ◽  
...  
Keyword(s):  
Functional Groups ◽  
Metal Organic Frameworks ◽  
Water Repellent ◽  
Humid Air ◽  
Metal Organic ◽  
The Stability

Diamond structure cannot be stable in nm-sized particles

2014 ◽  
Vol 70 (6) ◽  
pp. 1033-1034 ◽  
Author(s):  
Stepan S. Batsanov
Keyword(s):  
Functional Groups ◽  
Diamond Structure ◽  
The Stability ◽  
Bulk Diamond

The observed and calculated densities of nanodiamond cannot be reconciled, and the stability of diamond structure explained, if nanodiamond is regarded as a form ofpurecarbon. The surface-terminating hydrogen and functional groups are an integral part in the stability of these particles which therefore need not be as inert and non-toxic as bulk diamond, with important implications for nanomedicine.

The Structure and Stability of C20 Dimer

2015 ◽  
Vol 1096 ◽  
pp. 228-231
Author(s):  
Ting Ting Dai ◽  
Pei Ying Huo ◽  
Ji Cai Yu ◽  
Huan Liu ◽  
Yan Xia Song ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ground State ◽  
Electronic Structures ◽  
Density Functional ◽  
Ground State Structure ◽  
State Structure ◽  
Carbon Cage ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The Stability

The possible geometrical and electronic structures of C20dimer are optimized by using the density functional theory at B3LYP/LANL2DZ level, stable structure of C20dimer are obtained. The stability of the ground state structure have been studied. The results showed that: there was a slight expansion in carbon cage of C20 dimer ; its chemical stability and thermal stability have been improved.

Ethanol and Distillate Blends: A Thermodynamic Approach to Miscibility Issues

2010 ◽  
Author(s):  
Jean-Noe¨l Jaubert ◽  
Romain Privat ◽  
Michel Molie`re
Keyword(s):  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Functional Groups ◽  
Fossil Fuels ◽  
Chemical Properties ◽  
Physical Property ◽  
Diesel Oil ◽  
Group Contribution ◽  
Heat Of Mixing ◽  
The Stability

In the recent years, the quest for an ever wider cluster of sustainable primary energies has prompted an increasing number of attempts to combine the emission sobriety of bio fuels with the energy density advantage of fossil fuels. A number of compositions incorporating hydrocarbons, ethanol and in some cases limited amounts of water have been proposed, especially in the forms of micro emulsions, with a variable success. Indeed due to markedly different physical and chemical properties, ethanol and gasoil are able to blend and form homogeneous solutions only in limited proportion ranges. Indeed, such mixtures often give rise to liquid-liquid equilibrium. A key parameter is thus the Minimum Miscibility Temperature (MMT), i.e. the temperature above which ethanol and gasoil become completely miscible. In fact, commercial gasoils do not constitute a monolithic product but display in the contrary a large span of compositions that influence the stability of these blends. In this context, the LRGP laboratory (Laboratoire Re´actions et Ge´nie des Proce´de´s) has undertaken an investigation program intended to understand the factors underlying the stability of ethanol/gasoil blends. The approach is based on the calculation of the liquid-liquid phase diagrams formed by anhydrous ethanol and a mixture of various hydrocarbons representative of the diesel oil pool using the group contribution concept. Indeed, for correlating thermodynamic properties, it is often convenient to regard a molecule as an aggregate of functional groups; as a result, some thermodynamic properties (heat of mixing, activity coefficients) can be calculated by summing group contributions. In this study, the universal quasichemical functional group activity coefficient (UNIFAC) method has been employed as it appears to be particularly useful for making reasonable estimates for the studied non ideal mixtures for which data are sparse or totally absent. In any group-contribution method, the basic idea is that whereas there are thousands of chemical compounds of interest in chemical technology, the number of functional groups that constitute these compounds is much smaller. Therefore, if we assume that a physical property of a fluid is the sum of contributions made by the molecule’s functional groups, we obtain a possible technique for correlating the properties of a very large number of fluids in terms of a much smaller number of parameters that characterize the contributions of individual groups. This paper shows the large influence exerted by the paraffinic, aromatic and naphthenic character of the gasoil but also the sulfur content of the fossil fraction on the shape of the liquid-liquid phase diagram and on the value of the minimum miscibility temperature.

Investigating the Impact of Polymer Functional Groups on the Stability and Activity of Lysozyme–Polymer Conjugates

2016 ◽  
Vol 17 (3) ◽  
pp. 1123-1134 ◽  
Author(s):  
Melissa Lucius ◽  
Rebecca Falatach ◽  
Cameron McGlone ◽  
Katherine Makaroff ◽  
Alex Danielson ◽  
...  
Keyword(s):  
Functional Groups ◽  
Polymer Conjugates ◽  
The Stability ◽  
The Impact
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