Two thermochromic compounds. Preparations for the introductory organic laboratory

Ault, Addison; Kopet, Rachel; SERIANZ, A.

doi:10.1021/ed048p410

Cited by 9 publications

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“…1 ), which is intensely red, but loses its color when chilled to low temperature, the same phenomenon as in the case of dixanthylene may be assumed to occur, but in a different temperature range” 34. Ault, et al reported in 1971: “Dixanthylene is a pale yellow‐green solid at room temperature, but becomes dark blue when melted or heated in solution; at liquid nitrogen temperature, it is completely colorless” 35. These observations at low temperatures have never been confirmed experimentally.…”

Section: Resultsmentioning

confidence: 99%

Thermochromism at Room Temperature in Overcrowded Bistricyclic Aromatic Enes: Closely Populated Twisted and Folded Conformations

et al. 2007

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The overcrowded thermochromic bistricyclic aromatic enes (BAEs) 10-(9ЈH-fluoren-9Ј-ylidene)-9(10H)-anthracenone (6), 10-(11ЈH-benzo [b]fluoren-11Ј-ylidene)-9(10H)-anthracenone (7), and 10-(1Ј,8Ј-diaza-9ЈH-fluoren-9Ј-ylidene)-9(10H)-anthracenone (8) were synthesized by applying Barton's twofold extrusion diazo-thione coupling method and their crystal and molecular structures were determined. BAEs 6-8 exhibit thermochromic behavior at room temperature due to the equilibrium between the yellow anti-folded conformations and the thermochromic purple, blue, or red twisted conformations. The NMR experiments demonstrate a fast interconversion of the twisted and the anti-folded conformers of 6-8 in solution. BAE 7 readily undergoes E,Z-topomerization at room temperature with the coalescence point at 297 K and

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Section: Resultsmentioning

confidence: 99%

Thermochromism at Room Temperature in Overcrowded Bistricyclic Aromatic Enes: Closely Populated Twisted and Folded Conformations

et al. 2007

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“…When the thermochromism of molecular systems results from association with another chemical species such as a metal ion or proton or from modification of the medium by a thermal effect, the phenomenon is called "thermosolvatochromism" [13]. 9,9'-Bixanthenylidene, a typical thermochromic molecule, is colorless at liquid nitrogen temperature, yellow-green at room temperature and dark-blue when melted or heated in boiling mesitylene [14].…”

Section: Iii8 Thermochromismmentioning

confidence: 99%

Organic photochromism (IUPAC Technical Report)

Bouas‐Laurent

Dürr

2001

Pure and Applied Chemistry

853

578

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Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without theAbstract: This technical report is a general introduction to organic photochromism. The definition of photochromism (PC) is given together with that of words with the ending "chromism", such as thermo-, electro-, piezo-, and tribochromism. Important concepts such as two-photon, gated, dual-mode PC and chirochromism are illustrated. The concept of fatigue (chemical degradation) and the determination of the main photochromic parameters (number of cycles, cyclability, half-life), and the spectrokinetic and mechanistic aspects are discussed. The main families of PC (organic compounds and biological receptors) are illustrated with chemical formulae, and the different types of reactions involved in the photochromic processes (pericyclic reactions, E/Z isomerization, group transfer, etc.) are listed. Some examples of applications to "optical power limiting" substances, photoresponsive materials, and photoswitchable biomaterials are considered.

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“…Dixanthylidene 3 was synthesized by the method of Ault. 40 Neutral 3 was reduced with lithium following a variation of the procedure of Rabinowitz. 41 A piece of fresh lithium wire was placed in the upper part of an extended NMR tube which contained ca.…”

Section: Scheme 2 Tetra-deprotonation Ofmentioning

confidence: 99%

Antiaromatic Dianions: Dianions of Dixanthylidene by Reduction and Attempted Excited-State Deprotonation

2011

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Two thermochromic compounds. Preparations for the introductory organic laboratory

Abstract: Because of the interest students usually exhibit in preparing compounds with unusual properties, this lab allows students to prepare thermochromic compounds.

Cited by 9 publications

References 0 publications

Thermochromism at Room Temperature in Overcrowded Bistricyclic Aromatic Enes: Closely Populated Twisted and Folded Conformations

Thermochromism at Room Temperature in Overcrowded Bistricyclic Aromatic Enes: Closely Populated Twisted and Folded Conformations

Organic photochromism (IUPAC Technical Report)

Antiaromatic Dianions: Dianions of Dixanthylidene by Reduction and Attempted Excited-State Deprotonation

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