CROWN-ETHER STYRYL DYES - 24 - SYNTHESIS OF MULTIPHOTOCHROMIC 15-CROWN-5 ETHERS WITH RIGID SPACERS, THEIR ANION-CAPPED COMPLEXES, AND STEREOSPECIFIC [2-AUTOPHOTOCYCLOADDITION(2])
Sp. Gromov et al., CROWN-ETHER STYRYL DYES - 24 - SYNTHESIS OF MULTIPHOTOCHROMIC 15-CROWN-5 ETHERS WITH RIGID SPACERS, THEIR ANION-CAPPED COMPLEXES, AND STEREOSPECIFIC [2-AUTOPHOTOCYCLOADDITION(2]), Russian chemical bulletin, 47(1), 1998, pp. 97-106
Novel styryl dyes (trans-2a,b) containing a 15-crown-5 ether moiety an
d an N-sulfobenzyl spacer were synthesized. The reactions of trans-2a,
b with Mg(ClO4)(2) in MeCN afford dimeric complexes. During photolysis
of the latter, trans-cis isomerization to give anion-''capped'' compl
exes (cis-2a,b). Mg2+ and stereospecific [2+2] autocycloaddition to yi
eld cyclobutane derivative occur in parallel. The ratio of the two tra
nsformation pathways of dyes 2a,b depends on the spacer type. To inter
pret the experimental data, the molecular-mechanics and semiempirical
quantum-chemical calculations were performed.