Phase-hologram material by using four-center-type photopolymerization in the crystalline state

Organic photochemistry. XVII. Polymerization of unsaturated compounds by photocycloaddition reactions

“…60 In concentrated CHC13 solution, oligomerization of 58 probably occurred via isomerization of trans,trans-5& to trans,cis-58 and cis,cis-58, and photocycloadditions of all three isomers to produce various regioisomeric cyclobutane rings in the oligomer 59.60 X-ray diffraction and low temperature transmission electron microscopy studies of the crystal state photooligomerization (X >410 nm) of 58 showed that nu-cleation began and propagation proceeded within the defect-free structure. 51 In comparison to other related reactions studied, 58 had a medium reactivity. 51 A study of the morphological changes in the solid state photopolymerization of 58 showed the oligomer 59 was amorphous and the crystal did not change shape during the reaction.…”

“…53 The method of forming monomer 37 produced it in an oriented manner such that the double bonds were in the correct positions for undergoing cycloaddition (eq 19). This polymerization occurred only in the polymer matrix of 38.23 and picramide 57°0.015 Me, 58 crystal dispersed in H20 56, 57 58 0.42 M solution in CHC13 b 15 The amorphous methyl ester oligomer 59, formed by irradiation of the monomer 58 in the crystal state at 15 °C, probably contained a mixture of at least three stereoisomeric cyclobutanes that included both headto-head and head-to-tail units. [60][61][62] The head-to-head dimer 62 of 58 was formed topochemically in the ordered crystal at -10 °C during the first few hours of irradiation.…”

CNDO/2 calculations on the ethylenecyclobutane cycloaddition reaction

“…The various products resuhing from it can be utilized as photochromic dios [2], fungicides [3], polymers of reprographic [4] or holographic [5] interest. The solid phase photocyeloaddition of cynnamic aeid was the starting point in the development of such important theories as the topochemical principio and the solid state topotaxy [6].…”