scholarly journals Elimination Processes of Guest Molecules from the Inclusion Compounds of Deoxycholic Acid.

2003 ◽  
Vol 51 (1) ◽  
pp. 242-246 ◽  
Author(s):  
Takayoshi KIMURA ◽  
Yuichi KASAI ◽  
Tomohide TSUJIMOTO ◽  
Emi KAWAMURA ◽  
Tadashi KAMIYAMA ◽  
...  
Keyword(s):  
Inclusion Compounds ◽  
Deoxycholic Acid ◽  
Guest Molecules

Structural properties of the guest species in diacyl peroxide/urea inclusion compounds: an X-ray diffraction investigation

1990 ◽  
Vol 431 (1882) ◽  
pp. 245-269 ◽  
Keyword(s):  
Single Crystal ◽  
Structural Properties ◽  
Inclusion Compounds ◽  
X Ray Diffraction ◽  
Channel Axis ◽  
Guest Molecules ◽  
X Ray ◽  
Urea Inclusion Compounds ◽  
Diacyl Peroxide ◽  
Urea Inclusion

In this paper we report single crystal X-ray diffraction studies of urea inclusion compounds containing diacyl peroxides (dioctanoyl peroxide (OP), diundecanoyl peroxide (UP), lauroyl peroxide (LP)) as the guest component. In these inclusion compounds, the host (urea) molecules crystallize in a hexagonal structure that contains linear, parallel, non-intersecting channels (tunnels). The guest (diacyl peroxide) molecules are closely packed inside these channels with a periodic repeat distance that is incommensurate with the period of the host structure along the channel axis. Furthermore, there is pronounced inhomogeneity within the guest structure: within each single crystal, there are regions in which the guest molecules are three-dimensionally ordered, and other regions in which they are only one-dimensionally ordered (along the channel axis). Although it has not proven possible to ‘determine’ the guest structures in the conventional sense, substantial information concerning their average periodicities and their orientational relationships with respect to the host has been deduced from single crystal X-ray diffraction photographs recorded at room temperature. For OP/urea, UP/urea and LP/urea, the guest structure in the three-dimensionally ordered regions is monoclinic, and six types of domain of this monoclinic structure can be identified within each single crystal. The relative packing of diacyl peroxide molecules is the same in each domain, and the different domains are related by 60° rotation about the channel axis. For each of these inclusion compounds, the offset between the ‘heights’ of the guest molecules in adjacent channels is the same ( ca . 4.6 Å (4.6 x 10 -10 m)) within experimental error, suggesting that the relative interchannel packing of the guest molecules is controlled by a property of the diacyl peroxide group. In addition to revealing these novel structural properties, the work discussed in this paper has more general relevance concerning the measurement and interpretation of single crystal X-ray diffraction patterns that are based on more than one three-dimensionally periodic reciprocal lattice. Seven separate reciprocal lattices are required to rationalize the complete X-ray diffraction pattern from each diacyl peroxide/urea crystal studied here.

(Deoxycholic acid)2:Ferrocene:  A Phase Transition Determined by the Dynamic Behavior of the Included Guest Molecules

2000 ◽  
Vol 12 (5) ◽  
pp. 1314-1322 ◽  
Author(s):  
Matthias Müller ◽  
Alison J. Edwards ◽  
Keith Prout ◽  
W. Mark Simpson ◽  
Stephen J. Heyes
Keyword(s):  
Phase Transition ◽  
Dynamic Behavior ◽  
Deoxycholic Acid ◽  
Guest Molecules

Introducing new half-integer quadrupolar nuclei for solid state NMR of inclusion compounds

2015 ◽  
Vol 93 (9) ◽  
pp. 1014-1024
Author(s):  
Igor L. Moudrakovski ◽  
Christopher I. Ratcliffe ◽  
John A. Ripmeester
Keyword(s):  
Solid State ◽  
Gas Hydrates ◽  
Inclusion Compounds ◽  
Chemical Shift Anisotropy ◽  
Natural Abundance ◽  
Quadrupolar Nuclei ◽  
Guest Molecules ◽  
Quadrupolar Coupling ◽  
Nmr Techniques ◽  
The Impact

Broad developments in experimental NMR techniques have opened new and exciting opportunities for application of solid state nuclear magnetic resonance (SS NMR) in studies of gas hydrates and inclusion compounds in general. Perhaps the most important advance of the last 10 years was the extension into very high magnetic fields beyond 20 T. This progress is especially significant in studies concerned with low-γ, low natural abundance, and quadrupolar nuclei. This work reports our recent exploration of clathrate hydrates and other inclusion compounds (β-quinol, tert-Bu-Calix[4], and dodecasil-3C) with SS NMR of nuclei that were not so long ago completely out of reach for NMR, namely 131Xe, 83Kr, and 33S. Although 129Xe is a widely used NMR probe, applications of the low-γ isotope 131Xe were very scarce. Being a quadrupolar spin 3/2 nucleus, 131Xe provides an additional probe for sampling the electric field gradients in inclusion compounds. Another nucleus that has been seriously under-explored is 83Kr, with its very low γ being the main obstacle, and along with quadrupolar coupling we report the first detection of the chemical shift anisotropy in krypton. The relative values of the Sternheimer antishielding factors for 131Xe and 83Kr, obtained by comparison of the spectra of the two in identical cage environments, are also discussed. Though 33S NMR of solids is notoriously difficult due to its low γ, low natural abundance, and relatively large quadrupolar moment, working at the field of 21.1 T it was possible to acquire, in a reasonable time, natural abundance 33S SS NMR spectra of various H2S and SO2 gas hydrates and inclusion compounds. In most cases the spectra are dominated by the quadrupolar interactions, providing information on the symmetry of the cages encapsulating the guest molecules, and also show the effects of very rapid reorientation of the encaged H2S and SO2. The impact of the introduction of new NMR nuclei on hydrate research is discussed.

Solvent–guest control of two extremely similar tetrahydrofuran inclusion structures

2014 ◽  
Vol 70 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Jiabin Gao ◽  
Mohan M. Bhadbhade ◽  
Roger Bishop
Keyword(s):  
Crystal Structures ◽  
Inclusion Compounds ◽  
Crystal Form ◽  
Solvent Free ◽  
Guest Molecules ◽  
Crystal Forms ◽  
X Ray

Racemic 2,4,6,8-tetracarbomethoxybicyclo[3.3.0]octa-2,6-diene-3,7-diol, C16H18O10(1), was known previously to yield two solvent-free polymorphs and also a clathrate inclusion crystal form. Crystallization of (1) yields two inclusion compounds containing tetrahydrofuran (THF): (1)4·THF is obtained from a mixture of THF and methanol, whereas (1)2·THF is obtained from pure THF. The X-ray crystal structures reveal that the two compounds are extremely similar and that their host arrangements are essentially identical. They differ, however, in the proportion, orientation and host–guest interaction of the included THF molecules. The disordered guest molecules in (1)4·THF are oriented along the guest channel direction, whereas in (1)2·THF they lie across the channel. This unusual solvent–guest control of inclusion structures has implications relating to the formation of polymorphic structures and other competing crystal forms.

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