13C-Nuclear Magnetic Resonance-Spectral Studies of the Interactions of Metal Ions with Carbohydrates: use of Relaxation Probes

Ring-Opening Polymerization of a Benzylated 1,6-Anhydro-β-d-talopyranose and Synthesis of a New Polysaccharide, (1→6)-α-d-Talopyranan

“…There is much evidence that this type of oxygenic sequence can form relatively stable and reversible complexes with metal ions and/or other Lewis acids. [28][29][30] We examined the coordination behavior of PF 5 based on the fact that unexpected large amounts of PF 5 were necessary for the polymerization of 1. Figure 4 shows the 200 MHz 31 P NMR spectrum of the reaction mixture of 1 and PF 5 (10:2) in CD 2 Cl 2 at -60°C, which was measured ∼24 h after the polymerization had started.…”

“…The talopyranosidic residue in polymer 2 adopts a 4 C 1 conformation, resulting in the formation of the same “axial−equatorial−axial” sequence among the three benzyloxy groups as in the All monomer (Figure B). There is much evidence that this type of oxygenic sequence can form relatively stable and reversible complexes with metal ions and/or other Lewis acids. − We examined the coordination behavior of PF 5 based on the fact that unexpected large amounts of PF 5 were necessary for the polymerization of 1 . Figure shows the 200 MHz 31 P NMR spectrum of the reaction mixture of 1 and PF 5 (10:2) in CD 2 Cl 2 at −60 °C, which was measured ∼24 h after the polymerization had started.…”

“…There is much evidence that this type of oxygenic sequence can form relatively stable and reversible complexes with metal ions and/or other Lewis acids. [28][29][30] We examined the A narrow quartet at -37 ppm was attributed to POF 3 produced by the reaction of PF 5 with an NMR sample tube made of Pyrex glass. 31 The medium and broad resonances of a quintet at -78 ppm and a septet at -146 ppm were respectively assigned to the -PFO 4 group incorporated in the beginning of the polymer chains and the counter anions PF 6…”