Controlled self-assembly of bis(crown)stilbenes into unusual bis-sandwich complexes: structure and stereoselective [2+2] photocycloaddition
作者:Sergey P. Gromov、Artem I. Vedernikov、Natalia A. Lobova、Lyudmila G. Kuz'mina、Stepan S. Basok、Yuri A. Strelenko、Michael V. Alfimov、Judith A. K. Howard
DOI:10.1039/c0nj00780c
日期:——
shown by 1H NMR spectroscopy that symmetrical bis(crown)stilbenes (L) and small alkali and alkaline-earth metal cations form 1(L) ∶ 1(Mm+) and 1(L) ∶ 2(Mm+) complexes in MeCN solutions. In the case of large or hydrated metal cations such as Cs+, Rb+, K+, Ba2+, Sr2+, [Ca(H2O)x]2+ and stilbenes with a small crown-ether cavity as compared with the metal cation size, stable bis-sandwich complexes 2(L) ∶ 2(Mm+)
它是由示出1 H NMR光谱的是对称的双(冠)芪(L)和小碱金属和碱土金属阳离子形成1(L):1(M米+)和1(L):2(M米+)MeCN解决方案中的复合物。在较大或水合金属阳离子(例如Cs +,Rb +,K +,Ba 2 +,Sr 2 +,[Ca(H 2 O)x ] 2+)和丁苯醚中,冠醚空穴较小的情况下与金属阳离子的大小,稳定的双夹心络合物2(L):2(M m +)也可以形成。由双(18-冠-6)二苯乙烯与丙烷二铵离子也可制得稳定的双假夹心2:2络合物。阐明了冠醚大小,阳离子大小和性质对二苯乙烯光转化途径和产物组成的影响。双(假)三明治复合物经过有效的立体选择性[2 + 2]光环加成,主要生成新的1,2,3,4-四冠环丁烷的rctt异构体。通过X射线衍射证实了双(皇冠)对苯二甲酸酯和所获得的环丁烷的配合物的结构。