Crown partially filling with

Polar O—H bonds are found in molecules such as water and alcohols. Crystal structures of several crown ether complexes have indicated that the cavity need only be partially filled by water.260-262 Several host-guest complexes of alcohols with the pyridino crown (83) have been reported.263 Longer chain and branched alcohols do not in general form crystalline adducts with this ligand. 

Tanaka, Y. Otsuka, K. Terabe, S. Separation of enantiomers by capillary electrophoresis-mass spectrometry employing a partial filling technique with a chiral crown ether. J. Chromatogr., A 2000, 875, 323-330. 

Xia S, Zhang L, Lu M, Qiu B, Chi Y, Chen G. Enantiomeric separation of chiral dipeptides hy CE-ESI-MS employing a partial filling technique with chiral crown ether. Electrophoresis 2009 30 2837-2844. 

PMMA and other methacrylate and acrylate polymers are widely used in dentistry. PMMA is used for dentures and root canal sealants. Polymers of 2,2-bis[4-(2-hydroxy-3-methacry-loyolxypropoxy)phenyl]propane (BisGMA), triethyleneglycol dimethacrylate (TEGDMA), and urethane dimethacrylate (UDMA) are used in dental composite resins, most commonly with a silica filler. Such composite resins are used for filling cavities, reshaping, and restoring teeth and for full and partial crowns. 

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