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Volumn 9, Issue 13, 2007, Pages 2577-2580

Templated synthesis of desymmetrized [2]catenanes with excellent translational selectivity

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EID: 34547201954     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol070970s     Document Type: Article
Times cited : (31)

References (48)
  • 2
    • 0003570337 scopus 로고    scopus 로고
    • Diederich, F, Stang, P. J, Eds, Wiley-VCH: Weinheim, Germany
    • (b) Templated Organic Synthesis; Diederich, F., Stang, P. J., Eds.; Wiley-VCH: Weinheim, Germany, 1999.
    • (1999) Templated Organic Synthesis
  • 4
    • 0003542983 scopus 로고    scopus 로고
    • Sauvage, J.-P, Dietrich-Buchecker, C. O, Eds, Wiley-VCH: Weinheim, Germany
    • (b) Molecular Catenanes, Rotaxanes, and Knots; Sauvage, J.-P., Dietrich-Buchecker, C. O., Eds.; Wiley-VCH: Weinheim, Germany, 1999.
    • (1999) Molecular Catenanes, Rotaxanes, and Knots
  • 33
    • 33748245620 scopus 로고    scopus 로고
    • For examples of desymmetrized [2]catenanes with various degrees of control on translational selectivity, see: (a) Ashton, P. R, Perez-Garcia, L, Stoddart, J. F, White, A. J. P, Williams, D. J. Angew. Chem, Int. Ed. Engl. 1995, 34, 571-574
    • For examples of desymmetrized [2]catenanes with various degrees of control on translational selectivity, see: (a) Ashton, P. R.; Perez-Garcia, L.; Stoddart, J. F.; White, A. J. P.; Williams, D. J. Angew. Chem., Int. Ed. Engl. 1995, 34, 571-574.
  • 45
    • 34547149502 scopus 로고    scopus 로고
    • Red crystals suitable for X-ray single crystal analysis were obtained after diffusion of ether into a Me2CO solution of 5·2PF 6. Purple crystals of 6·2PF6 were obtained from a MeCN solution after diffusion of diisopropyl ether. For more cristallographic information, please see the crystallographic information files in the Supporting Information
    • 6 were obtained from a MeCN solution after diffusion of diisopropyl ether. For more cristallographic information, please see the crystallographic information files in the Supporting Information.
  • 46
    • 34547199425 scopus 로고    scopus 로고
    • Multiple [C-H⋯O] interactions are observed between several oxygen atoms in the polyether loops of the crown ether and one α-BPy proton, one p-phenylene proton, and one methylene proton of the dicationic cyclophane. The associated [H⋯O] distances are 2.61, 2.50, and 2.47 Å, respectively. The corresponding [C-H⋯O] angles are 165°, 127°, and 134°. In addition, there is [C-H⋯π] interaction between one of the H-4/8 protons of the inside DNP ring system and its proximal p-phenylene ring. The distances between the H atom and the centroid π-electron plane is 2.54 Å, and the corresponding [C-H⋯π] angle is 149°.
    • Multiple [C-H⋯O] interactions are observed between several oxygen atoms in the polyether loops of the crown ether and one α-BPy proton, one p-phenylene proton, and one methylene proton of the dicationic cyclophane. The associated [H⋯O] distances are 2.61, 2.50, and 2.47 Å, respectively. The corresponding [C-H⋯O] angles are 165°, 127°, and 134°. In addition, there is [C-H⋯π] interaction between one of the H-4/8 protons of the "inside" DNP ring system and its proximal p-phenylene ring. The distances between the H atom and the centroid π-electron plane is 2.54 Å, and the corresponding [C-H⋯π] angle is 149°.
  • 47
    • 34547206559 scopus 로고    scopus 로고
    • Two mechanisms are possible for the exchange between the two translational isomers. Either the dicationic cyclophane rotates through the center of the crown ether component, or the outer DNP ring system can sweep round the dicationic cyclophane by pirouetting about the included DNP ring system. According to studies by the Stoddart group on structually similar [2]catenanes, the latter one is the lower energy process as it requires least energy for the breakdown of donor-acceptor interactions. The typical associated activation barrier for Stoddart's systems is around 12 to 14 kcal mol -1. Correspondingly, those site exchange processes can be efficiently frozen out below -30 °C. For compounds 5·2PF6 and 6·2PF6, such activation barrier is difficult to measure on account of the absence of other isomers. However, they should be very similar to those reported systems, both of which involve the breaking of donor-acceptor interactio
    • 6, such activation barrier is difficult to measure on account of the absence of other isomers. However, they should be very similar to those reported systems, both of which involve the breaking of donor-acceptor interactions between BPy and the outer aromatic ring system.
  • 48
    • 34547225998 scopus 로고    scopus 로고
    • The electrostatic potential surfaces were generated with MOE2006, using the MMFF94x force field. MOE2006 is a product of the Chemical Computing Group, Montreal, Canada.
    • The electrostatic potential surfaces were generated with MOE2006, using the MMFF94x force field. MOE2006 is a product of the Chemical Computing Group, Montreal, Canada.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.