| Abstract: | A variety of nmr transient techniques demonstrate the absence of domain structures in powders of α- and β-cyclodextrins, dextran B512F, and their “deuterated” analogs where deuterium replaces exchangeable protons. Cyclodextrins and dextran are inferred to be homogeneously ordered and disordered one-phase systems, respectively. We show how erroneous results concerning the presence and sizes of rigid and mobile domains can be reached from the interpretations of two-component free induction decays and spin–lattice relaxation behavior of polysaccharides. In our approach, we have measured 1H free induction decays and lineshapes, and 1H spin–lattice and dipolar relaxation times, in addition to using Goldman–Shen experiments and 13C cross-polarization magic-angel sample spinning. Self-consistent nmr results are suggested as essential means to corroborate conclusions concerning domain structures in biopolymers. |
