118331-06-9Relevant academic research and scientific papers
Syntheses of Photoresponsive Cyclobutane-1,2-dicarbonyl-capped 2.n Diazacrown Ethers by Intramolecular Photocycloaddition and the Structures of their Lithium and Mercury(II) Complexes
Akabori, Sadatoshi,Kumagai, Takeshi,Habata, Yoichi,Sato, Sadao
, p. 1497 - 1505 (2007/10/02)
Photoresponsive cyclobutane-1,2-dicarbonyl-capped 2.n diazacrown ethers (7) have been prepared by intramolecular photocycloaddition of p,p'-trimethylenedicinnamoyl-capped 2.n diazacrown ethers (5); the cyclobutane-1,2-dicarbonyl-capped 2.1 diazacrown ether (7a) showed a highly selective complexing ability for the lithium cation, although (5) did not show any complexing abilities for alkali, alkaline-earth, and other metal ions.The crystal structures of (5a), the 1:1 lithium and mercury(II) thiocyanate complexes (8) and (9) of (7a) have been determined by X-ray analyses.The structures of (8) and (9) revealed that the configuration of the cyclobutane ring is in the β-form and slightly distorted.Complex (8) consists of dimeric molecules in which the lithium atom is directly bonded to the two oxygen atoms of the amido groups and the two nitrogen atoms of the thiocyanate group of the counter anion and adjacent complex in a slightly distorted tetrahedral configuration.The Hg atom in (9) is also bonded directly to the two oxygen atoms of the amido groups, the two sulphur atoms of the thiocyanate groups, and the simple nitrogen atom of the counter anion of the adjacent complex in a distorted trigonal bipyramidal configuration.
The Preparation of Photoresponsive Cyclobutanocrown Ethers by Means of Intramolecular Photocycloaddition
Akabori, Sadatoshi,Kumagai, Takeshi,Habata, Yoichi,Sato, Sadao
, p. 2459 - 2466 (2007/10/02)
The reaction of o-bis(3-hydroxy-1-oxapropyl)benzene (7b) with 3.3'-(trimethylenedi-4,1-phenylene)bisgave 8,9-benzo-4,7,10,13-tetraoxaparacyclopha-1,8,15-triene-3,14-dione (8b) in a 6,5percent yield, together with its dimer in a 12.3percent yield.Also, 5,6-benzo-4,7-dioxaparacyclopha-1,5,9-triene-3,8-dione (8a) and 11,12-benzo-4,7,10,13,16,19-hexaoxaparacyclopha-1,11,21-triene-3,20-dione (8c)were obtained by the same method in 7.0 and 8.0percent yields, together with their respective dimers (9a: 6.0percent, 9c: 20.8percent).X-Ray analysis of 8b revealed the two double bonds to be trans and the distances between the two olefinic carbon atoms (C17-C35) and (C18-C34) to be 5.341(11) and 5.906(9) Angstroem respectively.These distances are too long for intramolecular photocycloaddition to occur in the crystalline state.However, the irradiation of the solutions of the crown ethers 8a and 8b in acetonitrile by Pyrex-filtered UV light (>300 nm) gave two intramolecular photocycloadducts, cyclobutanocrown ethers 10a and 10b, in 95.7 and 91.8percent yields respectively.Subsequently, 10a and 10b were transformed to 8a and 8b in 37 and 29percent yields respectively upon irradiation with 220 nm UV light.The structures of 10a and 10b were confirmed to be the β-form.
