Zur Kenntniss der Acetylenbindung

Abstract

2) Allyleri gieht mit allialiwher Quet lisilberlosung nat 11 K u t i ch e r o f f Alleiiquetksilber (C,H&Hg, Allen dagegeri weder mit der \.on K u t s c h e r o f f angeaaiidten Losnug, iioch init ciner Losuiig voii Cyaiic~uec.ksilhe~-Cyaiilialium einen Niedeischlag.3) Das Tetrabromid des Allyleni ist flussig, dasjeiiige des Allcns erstarit bci -ISo, uiid JJird darimh erst bei Oo wieder flusig.Einleitung.Die Frage nach der Natur der Valenz, oder besser gesagt, der Affinitat spielt zur Zeit in der Cheinie eine dominirende Rolle. Die organische Chemie versucht dem Problem iiaher zu kommen, hauptsachlich durch Studium der ungesattigten Verbindungen. So ist das experimentelle Material iiber das Verhalten der Aethylenbindung in den letzteu Jahren ungeheuer angewachsen; lieine der zahlreichen Tlieorien vermag aber alle sich daraus ergebenden Seiten des grossen Problems zn umfassen.Die Acetylenbindung ist im Gegensatz dazu wenig untersucht, wohl weil erst in letzter Zeit die Arbeiteii yon J o s i t s c h 2), M o u r e u 3, und N e f 4 , einigermassen handliche Methodeii lehrten, die complicirtere Acetylenderivate darzustellen gestatten. Es

Isomerization of Diphenyl Polyenes. Part III. Absorption and Fluorescence Properties of 1,4-Diphenyl-1,3-butadiene in Poly(vinyl alcohol) Film

“…The fact that the X B* state lies below the *A* state of DPB in condensed media is consistent with spectroscopic observations for these molecules in supersonic jets [13][14][15][16]. Straus [17,18] obtained the following three expected steric forms of DPB: trans-trans, cistrans and cis-cis. Within a given stereoisomeric set, the all-trans compound occupies a privileged position, which means that its spectral band shows a longer wavelength maximum and a higher extinction value than the band of any eis isomer [19].…”

Organic Synthesis “On Water”

“…96 Among those, reactions of copper(I) acetylides date back as far as 1869, when Glaser discovered the oxidative coupling of terminal alkynes. 97,98 The scope of the reaction was extended in the subsequent studies by Baeyer, 99 Straus, 100,101 Reppe, 102 and Eglinton. 103 Heterocoupling reactions of copper(I) acetylides that do not involve oxygen have been reported by Castro and Stephens (with aryl halides), 104,105 and Cadiot and Chodkiewicz (with bromoalkynes).…”

Acetylenic Coupling: A Powerful Tool in Molecular Construction

“…With the use of potassium ferricyanide as the oxidizing agent, [2b] he simultaneously showed that dioxygen itself is not necessary for the coupling process. [15] The original Glaser reaction failed to see broad application because of the apparent need to isolate the potentially explosive copper acetylide before oxidation, which was often tedious in view of the poor crystallization properties of most copper salts. [3] Tetraacetylene dicarboxylic acid (HOOCÀ(CC) 4 ÀCOOH) was also likely generated in these experiments.…”