Conductance study of the complexation of substituted and lariat 16-crown-5 derivatives with alkali metal ions in nonaqueous solvents |
| |
| Authors: | Yasuyuki Takeda Itsumi Fujimaki Shinichi Ochiai Kazuhiko Aoki Yoshihiro Kudo Hiroaki Matsuda Yoshihisa Inoue Tadao Hakushi |
| |
| Institution: | (1) Department of Chemistry, Faculty of Science, Chiba University, Yayoi-cho, Chiba 260, Japan;(2) Department of Material Science, Faculty of Science, Himeji Institute of Technology, Kamigori, 678-12 Hyogo, Japan;(3) Department of Applied Chemistry, Faculty of Engineering, Himeji Institute of Technology, 2167 Shosha, Himeji, 671-22 Hyogo, Japan |
| |
| Abstract: | Formation constants (K
ML) of 1:1 complexes of 15-(2,5-dioxahexyl)-15-methyl-16-crown-5 (L16C5) and 15,15-dimethyl-16-crown-5 (DM16C5) with alkali metal ions were determined in acetonitrile (AN) and propylene carbonate (PC) by conductometry at 25°C. Except for the case of Li+-and K+-16C5 complexes in PC, the selectivity sequences of L16C5 and DM16C5 are identical with those of the parent crown ether 16-crown-5 (16C5) regardless of the solvent (AN, PC, methanol) (Na1 > Li+ > K+ > Rb+ > Cs+), which show the size-fit correlation. The selectivities of L16C5 and DM16C5 for the alkali metal ions are governed not by the sidearms but by the cavity size. The stability of the crown ether complex is dependent not on the dielectric constant but largely on the donor number of the solvent. TheK
ML(M1
+)/K
ML(M2
+) ratio of L16C5 or 16C5 varies very much with the solvent in the cases of M1=Na, M2=K and M1=Na, M2=Li, but that of DM16C5 is almost constant regardless of the solvent. |
| |
| Keywords: | Solvent and lariat effect 16-crown-5 derivatives alkali metal ions complex stability conductometry |
| 本文献已被 SpringerLink 等数据库收录！ |
|
