33654-54-5

Upstream product

• 116263-45-7 <2-(2,4,6-Cycloheptatrien-1-yl)-1-phenylethyliden>propandinitril 
• 1417619-45-4 7,8-dibromo-2-phenyl-1,7,8,8a-tetrahydroazulene-1,1-dicarbonitrile 
• 29647-95-8 2-(cyclohepta-2,4,6-trienyl)-1-phenylethan-1-one 
• 33654-51-2 3-Cyano-2-phenylazulen-1-carboxysaeure 

Downstream Products

• 937069-31-3 3-bromo-2-phenyl-azulene-1-carbonitrile 

Relevant academic research and scientific papers

Towards solar energy storage in the photochromic dihydroazulene-vinylheptafulvene system

Abstract One key challenge in the field of exploitation of solar energy is to store the energy and make it available on demand. One possibility is to use photochromic molecules that undergo light-induced isomerization to metastable isomers. Here we present efforts to develop solar thermal energy storage systems based on the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch. New DHA derivatives with one electron-withdrawing cyano group at position 1 and one or two phenyl substituents in the five-membered ring were prepared by using different synthetic routes. In particular, a diastereoselective reductive removal of one cyano group from DHAs incorporating two cyano groups at position 1 turned out to be most effective. Quantum chemical calculations reveal that the structural modifications provide two benefits relative to DHAs with two cyano groups at position 1: 1) The DHA-VHF energy difference is increased (i.e., higher energy capacity of metastable VHF isomer); 2) the Gibbs free energy of activation is increased for the energy-releasing VHF to DHA back-reaction. In fact, experimentally, these new derivatives were so reluctant to undergo the back-reaction at room temperature that they practically behaved as DHA to VHF one-way switches. Although lifetimes of years are at first attractive, which offers the ultimate control of energy release, for a real device it must of course be possible to trigger the back-reaction, which calls for further iterations in the future. Molecular solar thermal energy storage: Derivatives of the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch with only one cyano group at position 1 were prepared and investigated experimentally and theoretically. Compared to derivatives with two cyano groups, these compounds exhibit larger energy differences between DHA and VHF isomers and hence larger energy storage capacities, while the VHF to DHA back-reaction is on hold (see scheme).

On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

Background: The dihydroazulene (DHA)/vinylheptafulvene (VHF) system (with two cyano groups at C1) functions as a photo-/thermoswitch. Direct ionic bromination of DHA has previously furnished a regioselective route to a 7,8-dibromide, which by elimination was converted to a 7-bromo-substituted DHA. This compound has served as a central building block for functionalization of the DHA by palladium-catalyzed cross-coupling reactions. The current work explores another bromination protocol for achieving the isomeric 3-bromo-DHA and also explores the outcome of additional bromination of this compound as well as of the known 7-bromo-DHA.

A novel route to a bromo-cyano-substituted azulene and its exploitation in the construction of an acetylenic scaffold

A novel route to functionalized azulenes is devised from a dihydroazulene precursor. Thus, bromination of 1,1-dicyano-2-phenyl-1,8a-dihydroazulene followed by heating in the presence of bromide ions provides an efficient way to generate 3-bromo-1-cyano-2-

Light-Sensitive Dihydroazulenes: Alternative Synthesis - The Influence of Alkyl Substituents at the Five-Memeered Ring on the Photochromic Behaviour

Starting from cycloheptatrienylium tetrafluoroborate (8) the dihydroazulenes 1 were synthesized via substituted cycloheptatrienes 10 - 13 as intermediates.The dicyanovinyl derivatives 12 and 13 were transformed into vinylheptafulvenes 2 by dehydrogenation