Argentivorous molecules with two kinds of aromatic side-arms: intramolecular competition between side-arms
作者:Yoichi Habata、Yosuke Oyama、Mari Ikeda、Shunsuke Kuwahara
DOI:10.1039/c3dt00034f
日期:——
Three tetra-armed cyclens with two kinds of side-arms, 3′,5′-difluorobenzyl/4′-methylbenzyl, 3′,5′-difluorobenzyl/1′-naphthylmethyl, and 3′,5′-difluorobenzyl/9′-anthrylmethyl groups, were prepared by reductive amination of 1,7-bis(3′,5′-difluorobenzyl)-1,4,7,10-tetraazacyclododecane and the corresponding aromatic aldehydes in the presence of NaBH(OAc)3. The X-ray structures of the Ag+ complexes and Ag+-ion-induced 1H NMR spectral changes suggest that (i) the chemical shift changes of the protons at the 2′- and 6′-positions in the 3′,5′-difluorobenzyl/4′-methylbenzyl side-arms are dependent on the electron density on the adjacent substituted benzenes, and (ii) in the tetra-armed cyclens with 3′,5′-difluorobenzyl/1′-naphthylmethyl and 3′,5′-difluorobenzyl/9′-anthrylmethyl groups as side-arms, electron-rich aromatic rings preferentially cover the Ag+ ions incorporated into the ligand cavities, and 3′,5′-difluorobenzyl groups do not participate in the Ag+ interactions. The log K values were estimated using Ag+-ion-induced UV-vis spectral changes.
通过还原胺化 1,7-双(3′,5′-二氟苄基)-1,4,7,10-四氮杂环十二烷和相应的芳香化反应,制备了三种具有两种侧臂的四臂环烯,即 3′,5′-二氟苄基/4′-甲基苄基、3′,5′-二氟苄基/1′-萘甲基和 3′,5′-二氟苄基/9′-蒽甲基、在 NaBH(OAc)3 存在下,通过还原胺化 1,7-双(3′,5′-二氟苄基)-1,4,7,10-四氮杂环十二烷和相应的芳香醛制备而成。Ag+ 复合物的 X 射线结构和 Ag+ 离子引起的 1H NMR 光谱变化表明:(i) 3′,5′-二氟苄基/4′-甲基苄基侧臂中 2′-和 6′-位置的质子的化学位移变化取决于相邻取代苯的电子密度、(ii) 以 3′,5′-二氟苄基/1′-萘甲基和 3′,5′-二氟苄基/9′-蒽甲基作为侧臂的四臂环、富电子芳香环优先覆盖配体空腔中的 Ag+ 离子,3′,5′-二氟苄基不参与 Ag+ 相互作用。对数 K 值是通过 Ag+-离子诱导的紫外-可见光谱变化估算的。