Complexes of 6A-(2-amino-ethyl-amino)-6A-deoxy-b-cyclodextrin and 6A-deoxy-6A-[bis-(carboxyl-atomethyl)amino]-b-cyclodextrin with (R)- and (S)-tryptophanate and (R)- and (S)-phenyl-alaninate in aqueous solution. A pH-titrimetric and n.m.r. spectroscopic s
Date
1999
Authors
Sandow, M.
May, B.
Clements, P.
Easton, C.
Lincoln, S.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Australian Journal of Chemistry, 1999; 52(12):1143-1150
Statement of Responsibility
Conference Name
DOI
Abstract
<jats:p>
The 1 : 1 host–guest complexes formed by
6A-(2-aminoethylamino)-6A-deoxy-β-cyclodextrin
and (R)- and (S)-tryptophanate are
characterized by log(K/dm3
mol–1) = 4.83±0.02 and
4.72±0.03, respectively, and for those formed with
(R)- and (S)-phenylalaninate
log(K/dm3
mol–1) = 3.82±0.05 and
4.12±0.02, respectively, in aqueous solution at 298.2 K and
I = 0.10 mol dm–3
(NaClO4), where K is the stability
constant. The corresponding values for the analogous complexes formed by
6A-[bis(carboxylatomethyl)amino]-6A-deoxy-β-cyclodextrin
are 3.4±0.1, 3.3±0.1, 4.02±0.06 and 4.00±0.06,
respectively. Host–guest complexes are also formed by the monoprotonated
substituted β-cyclodextrins. 1H n.m.r. spectroscopy
(ROESY) indicates that the guests are complexed with their indole and phenyl
entities inside the annuli of the substituted β-cyclodextrin
hosts.</jats:p>