Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503, Japan.
Inorg Chem. 2011 Aug 15;50(16):7535-9. doi: 10.1021/ic200401g. Epub 2011 Jul 15.
Enantiopure crystals of K(1.3)Na(3.2)H(6.5)[l-Pr(PW(11)O(39))(2)]·8.3l-proline·21.5H(2)O (1), K(1.3)Na(3.2)H(6.5)[d-Pr(PW(11)O(39))(2)]·8.3d-proline·17H(2)O (2), and K(1.3)Na(3.2)H(6.5)[l-Er(PW(11)O(39))(2)]·8.3l-proline·22.5H(2)O (3) were successfully obtained by using l- and d-proline (pro) as chiral auxiliary agents. In these crystals, l- and d-Ln(PW(11)O(39))(2) anions are attached by two l- and d-pro molecules, respectively, through a O···N hydrogen-bonding interaction between the square-antiprismatic LnO(8) center and amino-N atoms. The l- and d-Pr(PW(11)O(39))(2) anions in aqueous solutions exhibited a couple of mirror-imaged CD spectra due to (3)H(4/2)→(3)P(0,1,2) and (1)D(2) transitions in the stereogenic Pr(3+) center. Chirality inductions by l- and d-pro from a racemic solution of Er(PW(11)O(39))(2) was demonstrated by means of CD spectroscopy.
手性晶体 K(1.3)Na(3.2)H(6.5)[l-Pr(PW(11)O(39))(2)]·8.3l-脯氨酸·21.5H(2)O (1)、K(1.3)Na(3.2)H(6.5)[d-Pr(PW(11)O(39))(2)]·8.3d-脯氨酸·17H(2)O (2)和 K(1.3)Na(3.2)H(6.5)[l-Er(PW(11)O(39))(2)]·8.3l-脯氨酸·22.5H(2)O (3)是通过使用 l-和 d-脯氨酸（脯氨酸）作为手性辅助剂成功获得的。在这些晶体中，l-和 d-Ln(PW(11)O(39))(2)阴离子通过四方反棱柱形 LnO(8)中心和氨基-N 原子之间的 O···N 氢键与两个 l-和 d-脯氨酸分子相连。在水溶液中，l-和 d-Pr(PW(11)O(39))(2)阴离子由于手性 Pr(3+)中心的 (3)H(4/2)→(3)P(0,1,2)和 (1)D(2)跃迁，表现出一对镜像的 CD 光谱。通过 CD 光谱证明了 l-和 d-脯氨酸从Er(PW(11)O(39))(2)的外消旋溶液中诱导手性。
