CONTROL OF THE THERMAL CIS TO TRANS ISOMERIZATIONS OF AZOBENZENE AND THIOINDIGO DERIVATIVES BY THE FORMATION OF SUPRAMOLECULAR H-BONDED ASSEMBLIES

Article abstract of DOI:10.1002/poc.610080111

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.