Exo- and endo-Isomers of Plumbylenes Supported by 1,3-Diethers of Calix[4]arene |
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| Authors: | Ryunosuke Kuriki Prof Youichi Ishii Dr Takuya Kuwabara |
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| Institution: | 1. Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo, 112-8551 Japan;2. Department of Chemistry and Biochemistry, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1, Otsuka, Bunkyo-ku, Tokyo, 112-8610 Japan |
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| Abstract: | Calix4]arene-plumbylene complexes PbCalixt-Bu(O)2(OR)2], where R=benzyl, 9-fluorenyl, SitBuMe2, and SiiPr3, have been synthesized by the reaction of Lappert's plumbylene PbN(SiMe3)2]2 with the corresponding 1,3-diethers of calix4]arene. The products have been fully characterized by 1H, 13C{1H}, and 207Pb NMR spectroscopy, elemental analysis, and X-ray diffraction analysis. The products adopt two different forms depending on the R groups: the alkyl derivatives were obtained as exo-isomers in which the lead atom resides outside the cavity of the calix4]arene, while the silyl derivatives were isolated as endo-isomers where the lead atom is situated inside the cavity. X-ray diffraction studies revealed that the lead(II) atoms in the exo- and endo-isomers are coordinated by the ethereal oxygen atoms (OR) and the aromatic rings (ArOR), respectively, which are maintained in solution as evidenced by 207Pb NMR studies. |
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| Keywords: | Calixarenes Lead Pi interactions Plumbylene Tetrylene |
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