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The title racemate-to-conglomerate transformation which occurs in the solid state on heating or contact with MeOH vapour has been studied by IR and DTA spectral measurements, microscopic observation, and by X-ray structural and X-ray powder diffraction analysis. 相似文献
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Shinji Inagaki Yoshiaki Fukushima Kazuo Kuroda Kazuyuki Kuroda 《Journal of colloid and interface science》1996,180(2):623
The first and second adsorption–desorption isotherms of water vapor on a new mesoporous material derived from kanemite have been measured. The isotherms show unusual type V isotherms and large hysteresis. The type V isotherms, which have never been observed for the other adsorbates, suggest that the mesoporous material has a hydrophobic surface, although the hydrophobicity decreased after treatment with water vapor because of rehydration of the surface. The significantly large hysteresis could be explained by the difference in contact angle between adsorption and desorption. 相似文献
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The title sterically crowded di-9-anthrylethyne derivative with 3,5-iPr2-phenyl groups at 1-position showed a barrier to rotation about the acetylenic axis of 18.0 kcal mol−1 based on a dynamic NMR study, which is an extremely high value for acyclic diarylethynes. The mechanism of the dynamic stereochemistry and the substituent effect on the rotational barrier are discussed. 相似文献
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Stability of porphyrin-calix[4]arene complexes analyzed by electrospray ionization mass spectrometry
Arai S Ishihara S Takeoka S Ohkawa H Shibue T Nishide H 《Rapid communications in mass spectrometry : RCM》2004,18(18):2065-2068
The stability of some porphyrin-calix[4]arene sodium-ion complexes were determined by a collision-activated decomposition (CAD) method utilizing electrospray ionization mass spectrometry (ESI-MS). Comparing the values of E(1/2), the collision energy at which the relative intensity of the complex ion is 0.5, we found that the porphyrin-calix[4]arene complex with the higher value of E(1/2) corresponded to that with the larger association constant (Kass), as measured by 1H-NMR in CDCl3. Both our ESI-MS and NMR studies proved that the number of hydrogen bonds and the rigidity of the calix[4]arene stabilized the complex. The ESI-MS technique could be successful in screening the binding affinity in host-guest systems with a small amount of sample. 相似文献