Solid-State Photodimerization of Guest Molecules in Inclusion Compounds

2006 ◽  
Vol 2006 (18) ◽  
pp. 4164-4169 ◽  
Author(s):  
Irena Zouev ◽  
Tali Lavy ◽  
Menahem Kaftory
Keyword(s):  
Solid State ◽  
Inclusion Compounds ◽  
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.

Dynamics of guest molecules in PHTP inclusion compounds as probed by solid-state NMR and fluorescence spectroscopy

2009 ◽  
Vol 11 (25) ◽  
pp. 4996 ◽  
Author(s):  
G. Srinivasan ◽  
J. A. Villanueva-Garibay ◽  
K. Müller ◽  
D. Oelkrug ◽  
B. Milian Medina ◽  
...  
Keyword(s):  
Solid State ◽  
Fluorescence Spectroscopy ◽  
Inclusion Compounds ◽  
Solid State Nmr ◽  
Guest Molecules

Tuning the configuration of the flexible metal–alkene-framework affords pure cycloisomers in solid state photodimerization

2021 ◽  
Author(s):  
Yong Wang ◽  
Meng-Fan Wang ◽  
David James Young ◽  
Hua Zhu ◽  
Fei-Long Hu ◽  
...  
Keyword(s):  
Solid State ◽  
Cycloaddition Reaction ◽  
Guest Molecules ◽  
Flexible Metal

The bulkiness of the guest molecules influences the conformations of the ligand and the final outcomes of the cycloaddition reaction.

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.

Solid-state NMR studies of non-ionic surfactants confined in mesoporous silica

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gerd Buntkowsky ◽  
Sonja Döller ◽  
Nadia Haro-Mares ◽  
Torsten Gutmann ◽  
Markus Hoffmann
Keyword(s):  
Solid State ◽  
Mesoporous Silica ◽  
Solid State Nmr ◽  
Role Models ◽  
Nmr Studies ◽  
Guest Molecules ◽  
Host Interactions ◽  
Functionalized Mesoporous Silica ◽  
Current Trends ◽  
Silica Materials

Abstract This review gives an overview of current trends in the investigation of confined molecules such as higher alcohols, ethylene glycol and polyethylene glycol as guest molecules in neat and functionalized mesoporous silica materials. All these molecules have both hydrophobic and hydrophilic parts. They are characteristic role-models for the investigation of confined surfactants. Their properties are studied by a combination of solid-state NMR and relaxometry with other physicochemical techniques and molecular dynamics techniques. It is shown that this combination delivers unique insights into the structure, arrangement, dynamical properties and the guest-host interactions inside the confinement.

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