Water guest molecules

Fig. 14. Choleic acid inclusion chemistry (a) crystal stmcture of DCA inclusion compound with phenanthrene (b) view along a DCA inclusion helix accommodating DMSO and water guest molecules (oxygen and sulfur atoms and methyl groups are represented by open circles and large and small black...

A 1 1 aquo complex was prepared with the chiral crown 1,3 1, 3 4,6 4, 6 -tetra-0-methylene-2,2 5,5 -bis-0-oxydiethylene-di-D-mannitol (9). In the crystal the host molecule has C2 symmetry, and the hydrogen bonded water guest molecule lies on the twofold axis. The oxygen atom of the water sits above the crown and is hydrogen bonded (H -O = 1.96 A) to two ether linkages adjacent to the six-membered rings. 

Herein we wish to report another approach, namely the use of the coordination complexes and bulky organosulfonate counter anions as building blocks, to generate porous ionic network which intercalates 1,10-phenanthroline or water guest molecules. The structures of adduct [Co(trien)(phen)](l,5NDS), 5 (phen)2 (H20)8 (1) and... 

Although 3b was not obtained as single crystals, the stmcture was easily estimated by XRPD measurement. For 3b, the intense peak observed at 7.6° for fresh sample shifted to 10.0°, meaning that the initial layer-layer distance was shortened about 2.7 A (Figure 2b). This value is consistent with that of effective space in 3a estimated from the X-ray structure. These results show that the dried complex 3b retains the two-dimensional framework. Exposure of solid sample of 3b to water vapor for three days reproduced 3a as confirmed by XRPD pattern measurement. That is, the dried complex 3b reversibly reincluded water molecules to reconstitute 3a. This structural conversion is classified as Type 1 since the nonporous and porous structures are reversibly obtained by forced release and contact of water guest molecules. 

Matsui and Mochida24) have determined the thermodynamic stabilities (log 1 /Kd) for a- and P-cyclodextrin complexes with a variety of alcohols (Table 2) and analyzed the results in connection with the physicochemical properties of the guest molecules by the multivariate technique. The log 1/Kd values were plotted against log Pe, where Pe is the partition coefficient of alcohol in a diethyl ether-water system. The plots for the a- and P-cyclodextrin complexes with eight 1-alkanols gave approximately straight lines with slopes of around one. 

Two helices are packed antiparallel in the orthorhombic unit cell. Association of the helices occurs through a series of periodic carboxylate potassium water - carboxylate interactions. An axial projection of the unit-cell contents (Fig. 23b) shows that the helices and guest molecules are closely packed. This is the first crystal structure of a polysaccharide in which all the guest molecules in the unit cell, consistent with the measured fiber density, have been experimentally located from difference electron-density maps. The final / -value is 0.26 for 54 reflections, of which 43 are observed, and it is based on normal scattering factors.15... 

Fic. 29. (continued)—(b) An axial projection of the unit cell shows that there is sufficient room for guest molecules in the middle along the short diagonal, such as the water molecule (open circle) bridging both chains. 

Three welan helices pass through the unit cell, as shown in Fig. 37b. Two of them, I and II, at (2A A0) and ( A2A0), are antiparallel as in gellan. A third helix, III, at (000) is new and parallel to the first. They are equilaterally 12.0 A apart from each other, 2.9 A farther than in 41. The unit cell contains a total of nine pentasaccharides surrounded by ordered guest molecules, which are accounted by six calcium ions and 75 water molecules. The two up and down helices interact via side chains, calcium ions, and/or water molecules. Specifically, helices I and II are linked only by side chain side chain hydrogen bonds... 

A carboxylate derivative of a fully aromatic, water-soluble, hyperbranched polyphenylene is considered as a unimolecular micelle due to its ability to complex and solubilize non-polar guest molecules [23]. The carboxylic acid derivative of hyperbranched polyphenylene polymer (HBP) (My,=5750-7077, Mn=3810-3910) consists of 40-60 phenyl units that branch outward from a central point forming a roughly spherical molecule with carboxylates on the outer surface. The free acid form of HBP was suspended in distilled water and dissolved by adding a minimum quantity of NaOH. The solution was adjusted to pH 6.2 with aqueous HCl. Calcium carbonate crystals were growth from supersaturated calcium hydrogencarbonate solution at room temperature. HBP gave... 

Inspection of Table 13-1 shows that the number of water molecules required to form the hydrate increases with the size of the guest molecule to be captured. Hydrates are classified into simple and mixed hydrates depending on whether one or more host or guest molecules compose the compound. They also exhibit different structures. 

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