,Z.

Faysal Ilhan1, Daniel S Tyson, Daniel J Stasko

  • 1Polymers Branch, Materials and Structures Division, NASA Glenn Research Center, 21000 Brookpark Road, Cleveland, Ohio 44135, USA.

概括

合成和表征了一种新的Z形烯二氧化物染色体. 这种新分子表现出强烈的光和固态应用的潜力,这是由于exciplex形成.

相关概念视频

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¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

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Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
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Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
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Structures of Aldehydes and Ketones

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In aldehydes (Figures 1a and 1b), the carbonyl...
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