Interaction of Polar Groups with a Bulky Hydrocarbon Residue: Polarizability and Steric Effects

2005 ◽  
Vol 70 (3) ◽  
pp. 370-382 ◽  
Author(s):  
Stanislav Böhm ◽  
Otto Exner
Keyword(s):  
Steric Effect ◽  
Extreme Case ◽  
Steric Effects ◽  
Enthalpies Of Formation ◽  
Straight Chain ◽  
Polar Groups ◽  
Sterically Demanding ◽  
Additive Rule ◽  
Stabilization Energies ◽  
The Individual

Energies of two series of branched hydrocarbon monosubstituted derivatives, 2-substituted 2-methylpropanes and 1-substituted bicyclo[2.2.2]octanes with 19 different substituents were calculated at the B3LYP/6-311+G(d,p) level and compared with the energies of straight-chain 1-substituted butanes. The comparison was carried out in terms of isodesmic homodesmotic reactions, in which the substituent is transferred from one hydrocarbon residue to another. The branched derivatives are mostly stabilized, in the extreme case by as much as 30 kJ mol-1 confirming that the additive rule used for estimating the enthalpies of formation is not valid for branched derivatives. The stabilization energies ∆E for the individual substituents X are not proportional to any known substituent parameters. In the qualitative respect, they are controlled by the first atom of the substituent - similarly as in the straight-chain isomers - but in the case of sterically demanding substituents they are perturbed by a destabilizing steric effect.

scholarly journals Differential steric effects in the inelastic scattering of NO(X) + Ar: spin–orbit changing transitions

2019 ◽  
Vol 21 (26) ◽  
pp. 14173-14185 ◽  
Author(s):  
M. Brouard ◽  
S. D. S. Gordon ◽  
B. Nichols ◽  
V. Walpole ◽  
F. J. Aoiz ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Steric Effect ◽  
Steric Effects ◽  
Spin Orbit ◽  
First Time

The differential steric effect for spin–orbit changing collisions of NO with Ar is determined for the first time.

scholarly journals Study of Kinetics, Equilibrium and the Influence of Steric Effects on Proton-Transfer in the Reactions of 2, 2, 4- and 2, 6- Substituted Anilines with 2-Phenoxy-3,5-dinitropyridine in DMSO

2010 ◽  
Vol 7 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Basim H. Asghar
Keyword(s):  
Proton Transfer ◽  
Steric Effect ◽  
Nucleophilic Attack ◽  
Steric Effects ◽  
Substituted Anilines ◽  
Phenoxy Group ◽  
Kinetics Studies ◽  
Zwitterionic Intermediate ◽  
Rate Limiting ◽  
Step Mechanism

Kinetic and equilibrium results for the reactions of 2-phenoxy-3,5-dinitropyridine (1), with a series of 2, 2, 4- and 2, 6- substituted anilines (2a-f), in the presence of DABCO in DMSO are reported. The reactions yield the 2-anilino derivatives (5), without the accumulation of intermediates. Kinetics studies are compatible with a two-step mechanism involving initial nucleophilic attack by amine at the ring carbon substituted by phenoxy group followed by either base-catalyzed or uncatalyzed conversion to the product. The base-catalyzed pathway is likely to involve rate-limiting proton-transfer from the zwitterionic intermediate to base. This work indicates a steric effect to proton transfer in reactions involving 2, 6-disubstituted anilines. The results were compared with those for reactions of 1, 3, 5-trinitrobenzene with anilines.

scholarly journals Adapting the Medium: Dynamics of Intermedial Adaptation in Contemporary Japanese Popular Visual Culture

2015 ◽  
Vol 10 (1) ◽  
pp. 141-152
Author(s):  
Beáta Pusztai
Keyword(s):  
Extreme Case ◽  
Unique Case ◽  
Adaptation Studies ◽  
Different Types ◽  
Contemporary Media ◽  
The One ◽  
The Individual ◽  
Original Story ◽  
Live Action

Abstract With respect to adaptation studies, contemporary Japanese popular culture signifies a unique case, as different types of media (be those textual, auditive, visual or audio-visual) are tightly intertwined through the “recycling” of successful characters and stories. As a result, a neatly woven net of intermedial adaptations has been formed - the core of this complex system being the manga-anime-live-action film “adaptational triangle.” On the one hand, the paper addresses the interplay of the various factors by which the very existence of this network is made possible, such as the distinctive cultural attitude to “originality,” the structure of the comics, animation and film industries, and finally, the role of fictitious genealogies of both traditional and contemporary media in the negotiation of national identity. On the other hand, the essay also considers some of the most significant thematic, narrative, and stylistic effects this close interconnectedness has on the individual medium. Special attention is being paid to the nascent trend of merging the adaptive medium with that of the original story (viewing adaptation as integration), apparent in contemporary manga-based live- action comedies, as the extreme case of intermedial adaptation. That is, when the aim of the adaptational process is no longer the transposition of the story but the adaptation (i.e. the incorporation) of the medium itself- elevating certain medium-specific devices into transmedial phenomena.

scholarly journals Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar

2015 ◽  
Vol 6 (4) ◽  
pp. 2202-2210 ◽  
Author(s):  
B. Nichols ◽  
H. Chadwick ◽  
S. D. S. Gordon ◽  
C. J. Eyles ◽  
B. Hornung ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Quantum Interference ◽  
Steric Effect ◽  
Steric Effects

New measurements of the differential steric effect for NO + Ar inelastic scattering highlight the importance of quantum interference.

Far-Infrared Spectra of Saturated Esters

1968 ◽  
Vol 22 (6) ◽  
pp. 697-713 ◽  
Author(s):  
J. E. Saunders ◽  
J. J. Lucier ◽  
F. F. Bentley
Keyword(s):  
Ir Spectra ◽  
Infrared Spectra ◽  
Frequency Characteristic ◽  
Far Infrared ◽  
Empirical Correlations ◽  
Straight Chain ◽  
Structural Differences ◽  
Characteristic Group ◽  
The Individual ◽  
Far Infrared Spectra

The ir spectra of 89 saturated aliphatic-branched and straight-chain esters are reported for the region 350–50 cm−1 and empirical correlations of the band frequencies are classified by the alcohol component. It is found that there is no consistent series of bands for all samples studied but within the individual classes, several discrete areas of absorption are specified. This verified that these vibrations are more sensitive to structural differences than the higher-frequency characteristic group frequencies and are more specific in the total identification of a given, sample.

scholarly journals Cancelation of Deglacial Thermosteric Sea Level Rise by a Barosteric Effect

2020 ◽  
Vol 50 (12) ◽  
pp. 3623-3639
Author(s):  
Geoffrey Gebbie
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Steric Effect ◽  
Three Dimensional ◽  
Steric Effects ◽  
Last Deglaciation ◽  
Effect Analysis ◽  
Height Change ◽  
The Last Deglaciation ◽  
The Last Glacial

AbstractSea level rise over the last deglaciation is dominated by the mass of freshwater added to the oceans by the melting of the great ice sheets. While the steric effect of changing seawater density is secondary over the last 20 000 years, processes connected to deglacial warming, the redistribution of salt, and the pressure load of meltwater all influence sea level rise by more than a meter. Here we develop a diagnostic for steric effects that is valid when oceanic mass is changing. This diagnostic accounts for seawater compression due to the added overlying pressure of glacial meltwater, which is here defined to be a barosteric effect. Analysis of three-dimensional global seawater reconstructions of the last deglaciation indicates that thermosteric height change (1.0–1.5 m) is counteracted by barosteric (−1.9 m) and halosteric (from −0.4 to 0.0 m) effects. The total deglacial steric effect from −0.7 to −1.1 m has the opposite sign of analyses that assume that thermosteric expansion is dominant. Despite the vertical oceanic structure not being well constrained during the Last Glacial Maximum, net seawater contraction appears robust as it occurs in four reconstructions that were produced using different paleoceanographic datasets. Calculations that do not account for changes in ocean pressure give the misleading impression that steric effects enhanced deglacial sea level rise.

Sugar-Cane Wax. II. An Examination of the Constituents of Sugar-Cane Cuticle Wax by Gas Chromatography

1960 ◽  
Vol 13 (4) ◽  
pp. 498 ◽  
Author(s):  
ZH Kranz ◽  
JA Lamberton ◽  
KE Murray ◽  
AH Redcliffe
Keyword(s):  
Gas Chromatography ◽  
Sugar Cane ◽  
Carbon Number ◽  
Straight Chain ◽  
The Individual ◽  
Major Hydrocarbon ◽  
Long Chain

Sugar-cane cuticle wax previously found to consist of long-chain aldehydes, alcohols, acids, and hydrocarbons (Lamberton and Redcliffe 1960) has been re-examined by gas chromatography to identify and estimate the individual constituents. The aldehydes, alcohols, and acids, all straight chain, are principally of even carbon number in each instance with the C28 member predominant, but appreciable amounts of odd carbon homologues are also present. The hydrocarbons are also of odd and even carbon number but with the odd members in greater amounts and n-heptacosane as the major hydrocarbon constituent.

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