Cyclodextrins (CDs) have been found to form inclusion complexes with poly(ε-caprolactone)
(PEC) to give crystalline compounds. α- and γ-CD formed complexes with these polyesters in high yields,
although β-CD gave complexes in moderate yields. The yields of the complexes decreased with increasing
molecular weight of the polymer. α-CD−PEC complexes are stoichiometric one-to-one (cyclodextrin:monomer unit) compounds, and γ-CD−PEC complexes are one-to-two compounds when the molecular
weights of PEC are low. The complexes were isolated and characterized by 1H NMR, 13C CP/MAS NMR,
and X-ray diffraction studies. The inclusion modes are discussed.
Cyclodextrins (CDs) were found to form inclusion complexes with aliphatic polyesters [-O(CH2)xOCO(CH2)4CO]n (where x ) 2, 3, or 4) to give crystalline compounds. R-and γ-CD formed complexes with these polyesters in high yields, although β-CD gave complexes in moderate yields. Although the yields of the complexes of R-CD with poly(trimethylene adipate) (PTA) (x ) 3) and poly-(1,4-butylene adipate) (PBA) (x ) 4) decreased with increasing molecular weight, R-CD formed complexes with poly(ethylene adipate) (PEA) (x ) 2) in high yields even at higher molecular weights. The yields of the complexes of γ-CD with these polyesters showed a maximum at the molecular weight of 1000. The complexes were isolated and characterized by FTIR, 1 H NMR, 13 C CP/MAS NMR spectra, and X-ray diffraction studies. The inclusion modes are discussed.
A significant fraction of superfluid helium nanodroplets produced in a free-jet expansion has been observed to gain high angular momentum resulting in large centrifugal deformation. We measured single-shot diffraction patterns of individual rotating helium nanodroplets up to large scattering angles using intense extreme ultraviolet light pulses from the FERMI free-electron laser. Distinct asymmetric features in the wide-angle diffraction patterns enable the unique and systematic identification of the three-dimensional droplet shapes. The analysis of a large data set allows us to follow the evolution from axisymmetric oblate to triaxial prolate and two-lobed droplets. We find that the shapes of spinning superfluid helium droplets exhibit the same stages as classical rotating droplets while the previously reported metastable, oblate shapes of quantum droplets are not observed. Our three-dimensional analysis represents a valuable landmark for clarifying the interrelation between morphology and superfluidity on the nanometer scale.
Poly(c-caprolactone) was found to form inclusion complexes with a-cyclodextrin to give crystalline compounds. The complexes are stoichiometric one-to-one (cyclodextrin : monomer unit) compounds. The yields of the complexes decreased with increasing the molecular weight of the polymer. They were characterized by IR, 'H NMR, 13C CP/MAS NMR, and X-ray diffraction. The inclusion modes are discussed.
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