Diene Conformation
Diene Conformation - Related Videos
01:20
Conformity
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2020
Conformity is the change in a person’s behavior to go along with the group, even if that person does not agree with the group. Asch’s Original Study Solomon Asch conducted several experiments in the 1950s to determine how people are affected by the thoughts and behaviors of other people. In one study, a group of participants was shown a series of printed line segments of different lengths: a, b, and c. Participants were then shown a fourth line segment: x. They were asked to identify which...
08:55
A Minority of One: Conformity to Group Norms
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2023
Source: William Brady & Jay Van Bavel—New York University It is obvious that we are influenced by those around us, but in the early to mid 1900's, psychologists began to study how potent social influence can be on our thoughts and behaviors. Motivated in part by attempts to explain the behaviors of Nazi soldiers in World War II, one topic of considerable interest at the time in psychology was conformity, the phenomenon in which people match their attitudes, behaviors, or beliefs to group...
01:29
Diels–Alder Reaction: Characteristics of Dienes
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2023
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction. Characteristics of the diene Conformation The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
10:37
Spatial Separation of Molecular Conformers and Clusters
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Cited by 3 •
2014
We present a technique that allows the spatial separation of different conformers or clusters present in a molecular beam. An electrostatic deflector is used to separate species by their mass-to-dipole moment ratio, leading to the production of gas-phase ensembles of a single conformer or cluster stoichiometry.
01:28
Stability of Conjugated Dienes
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2023
Introduction A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs. The two main factors contributing to the enhanced stability of conjugated systems are the delocalization of π electrons and the sp2 hybridization of the carbons forming the single bonds. Planar Conformers of Conjugated Dienes Conjugated dienes adopt two planar configurations, s-cis and s-trans,...
FAQs
The preferred arrangement reflects a balance between steric interactions and conjugation. The s-trans geometry can reduce unfavorable crowding between groups near the diene, while both arrangements retain the influence of conjugated orbital overlap. Comparing these effects helps explain why the lower-energy conformation is not determined by double-bond placement alone.
Rotation about the single bond between the double bonds changes the relative orientation of the two π-bonded regions, allowing interconversion between s-cis and s-trans forms. The double bonds themselves restrict rotation, so the central single bond provides the principal conformational flexibility. This motion changes molecular energy and orbital alignment.
In the s-cis arrangement, the terminal carbon atoms of the diene are brought closer together and positioned for the bond-forming pattern required in a Diels-Alder cycloaddition. Conformation therefore becomes part of mechanistic analysis: it indicates whether the diene already has a geometry suitable for forming the cyclic product.
First locate the two carbon-carbon double bonds and then examine the orientation around the single bond connecting them. If the diene chain bends so the terminal carbon atoms lie on the same side, it represents s-cis; an arrangement placing them on opposite sides represents s-trans. This comparison uses geometry rather than molecular rotation alone.
Prediction requires weighing steric interactions against the effects of conjugation. Crowding between portions of the diene can disfavor one orientation, whereas orbital overlap associated with conjugation influences molecular energy. Evaluating both contributions provides a basis for identifying the more stable conformation instead of assuming that s-cis or s-trans is always preferred.
Conformational analysis connects a diene's structure with its likely chemical behavior. Identifying whether the molecule can adopt the s-cis arrangement helps assess its suitability for cycloaddition, while the relative stability of the available conformations informs mechanistic reasoning. This makes conformation useful when interpreting reactions and planning transformations involving conjugated dienes.