Preferential inclusion of nitrophenoxide ion over its conjugate acid in polycationic cyclodextrin: pK a decrease of nitrophenols by host-guest interaction with diethylaminoethyl-cyclodextrins

Polyrotaxane derivatives. II. Preparation and characterization of ionic polyrotaxanes and ionic slide‐ring gels

“…As shown in Figure 2, 1 H NMR spectra of all ionic derivatives showed signals attributed to the protons in the introduced functional groups (see the Experimental section for details), consistent with the results of the analogous derivatives of CDs or other polysaccharides 54, 56–60, 63–66. NMR spectra of 13 C also exhibited signals characteristic to each derivative, supporting the introduction of the desired functional groups.…”

“…DEAE-CDs have been reported as showing similar discoloration to brown when the counter ions of diethylaminoethyl groups were hydroxides, and no change in color was observed when the counterions were chlorides. 63 The present DEAE-PR sample also showed a tendency of discoloration, although it is expected to have chloride counterions by final neutralization with 4 M HCl in the purification steps.…”

“…62 The DEAE-PR (4) was prepared by etherification with DEAE-Br, similar to the synthesis of DEAE-CDs. 63 The obtained DEAE-PR was a pale-brown solid, which turned dark brown after storage for 1 month. DEAE-CDs have been reported as showing similar discoloration to brown when the counter ions of diethylaminoethyl groups were hydroxides, and no change in color was observed when the counterions were chlorides.…”

“…The DEAE‐PR ( 4 ) was prepared by etherification with DEAE‐Br, similar to the synthesis of DEAE‐CDs 63. The obtained DEAE‐PR was a pale‐brown solid, which turned dark brown after storage for 1 month.…”

“…consistent with the results of the analogous derivatives of CDs or other polysaccharides. 54,[56][57][58][59][60][63][64][65][66] NMR spectra of 13 C also exhibited signals characteristic to each derivative, supporting the introduction of the desired functional groups. Although the FTIR results for CM-PR300 and DEAE-PR indicated absorptions corresponding to the carboxymethyl and diethylaminoethyl groups, respectively, those for SE-PR and QA-PR did not display sufficient absorptions resulting from the introduced groups, probably because of their low DS values, as shown in the following results.…”