42917-57-7Relevant academic research and scientific papers
CONTROL OF THE THERMAL CIS TO TRANS ISOMERIZATIONS OF AZOBENZENE AND THIOINDIGO DERIVATIVES BY THE FORMATION OF SUPRAMOLECULAR H-BONDED ASSEMBLIES
Rosengaus, Jacqueline,Willlner, Itamar
, p. 54 - 62 (1995)
2,3-Bis(aminocyclohexyl)-6-methoxy-1,3,5-triazine (1a) forms intermolecular H-bonded complexes with 3,3'-diacetyl-cis-azobenzene (4b) and 6,6'-diethoxy-cis-thioindogo (5b), (association constants K=4.9*104 and 3.5*105 l mol-1, respectvively).The thermal cis->trans isomerization of 4b and 5b to 3,3'-diacetyl-trans-azobenzene (4a), and 6,6'-diethoxy-trans-thioindigo (5a), is inhibited in the intermolecular complex 1a-4b and 1a-5b.Molecular mechanics calculations support the formation of the intermolecular H-bonded complexes between 1a and 4b or 5b.
USE OF NITROBENZENE FOR PREVENTING THE CATALYTIC ACTION OF TRACE IMPURITIES ARISING DURING PHOTOISOMERIZATION OF THIOINDIGO IN BENZENE SOLUTIONS.
Mostoslavskii,Nazar'ko
, p. 1280 - 1282 (2007/10/02)
The persistence of an image on a photochromic material depends on the thermal stability of the photoinduced form. Identification of the factors tending to lower the rate constant of spontaneous transition of the thermodynamically unstable into the stable form is examined. It is shown that (1) Nitrobenzene added before irradiation in amounts 1-10% to a solution of thioindigo in benzene does not inhibit photochemical formation of trace impurities; (2) addition of an equal amount (by volume) of nitrobenzene immediately after irradiation of a solution in benzene lowers the rate constant by a factor of 10-20; the constant becomes lower by a factor of 3 than in a chromatographically purified benzene solution of the Z isomer but remains 13 times as high as in nitrobenzene itself, and approximately equal to the rate constant in nitrobenzene containing 10** minus **3 mole multiplied by (times) liter** minus **1 of such active catalysts of Z yields E isomerization as p-toluenesulfonic acid or dibutylamine.
