Kazuaki Yokota

Synthesis of poly(dibenzo-19-crown-6) via cyclopolymerization of diepoxide

SummarySynthesis and cyclopolymerization of 5,6;14,15-dibenzo- 1, 2; 18, 19-diepoxy- 4, 7, 10, 13, 16-pentaoxanonadeca- 5,14-diene (3) was carried out. The polymerization of 3 with tin tetrachloride and boron trifluoride etherate gave the polymers with lower molecular weight. Alternatively, triethylaluminium-water-acetylacetone (Vandenberg catalyst) was effective in preparing polymers of high molecular weight which were soluble in p-cresol and p-chlorophenol. The polymers were essentially composed of cyclic constitutional units corresponding to dibenzo-19-crown-6. The cation-binding ability of the polymer showed the highest selectivity for K+.

Polymeric chiral crown ethers

SummaryCopolymerizations of (S)-3,3′-dimethyl-2,2′-bis[2-(2-vinyloxyethoxy)ethoxy]-1, 1′-binaphthyl (S-MVN) or 1,3:4,6-di-O-benzylidene-2,5-bis-O-[2-(2-vinyloxyethoxy)ethyl]-d-mannitol (D-BVM) with isobutyl vinyl ether (IBVE) were carried out with BF3·OEt2 in CH2Cl2 at 0 °C. The copolymers obtained were soluble in CHCl3 and THF, and consited of (S)-binaphtho-21-crown-6 or d-manno-21-crown-6 units and IBVE, i.e., poly(S-DVN-co-IBVE) and poly(D-BVM-co-IBVE). These host copolymers dominantly formed complexes with l-phenylglycine methyl ester, whose properties were similar to those for homopolymers of S-MVN and D-BVM.

Synthesis of polymers with cryptand-like units via radical cyclopolymerization of diacrylate and dimethacrylate derived from diaza-12-crown-4, and the binding property for lithium ion

SummaryPolymers with cryptand-like units have been obtained by the radical cyclopolymerization of 4,10-bis(acryloyloxyethyl)- and 4,10-bis(methacryloyloxyethyl)-1,7-dioxa-4,10-diazacyclododecane. The polymers consist of only bicyclic constitutional units, though having fairly low molecular weight. In the complexation with alkali-metal ions, the participation of the cavity effect for Li+ ion and the cooperative effect of neighbouring ligands for the larger ions is a characteristic of the polymers, thereby giving high binding ability for every ion, but low selectivity.

Synthesis of poly(hemispherand) via cyclopolymerization of diepoxide

SummaryCyclopolymerization of 2,6-bis[3-(4,5-epoxy-2-oxapentyl)-2-methoxy-5-methylphenyl]-4-methylanisole was carried out with cationic, anionic, and coordination catalysts. The polymers obtained with BF3·OEt2 or SnCl4 in dichloromethane and with t-BuOK in DMSO were soluble in benzene, chloroform, and THF. The mole fractions of the cyclic units in these polymers were from 0.65 to 0.75. The resulting poly(hemispherand) bound alkali metal cations and the selectivity was in the order of Rb+>K+>Cs+>Na+>Li+.