Molecular inclusion complexes

Figure 1 shows the crystal structure of the 5,10 12,17 19,24 26,3-tetrakis (dimethyl-siladioxa)-l, 8,15,22-tetramethyl[l4]metacyclophane cavitand (7) which has an enforced cavity appropriately sized to include only slim linear guests 12b). This cavitand forms crystals of a 1 1 molecular inclusion complex with CS2, the guest species being almost entirely encapsulated within the host cavity 27). The crystal structure of the complexed... 

Itraconazole oral solution contains 10 mg of itraconazole per milliliter, solubilized by hydroxypropyl-(beta)-cyclo-dextrin (400 mg/mL) as a molecular inclusion complex. The solution is clear and yellowish in color with a target... 

A simple possibility for the synthesis of esters, the reaction of an acid chloride with an alcohol, was used by Schrage and Vogtle [58] for a two-step synthesis of the macrocycle 63 from the alcohol 61 and the acid chloride 62. Compound 63, an example from the field of host/guest chemistry, forms a cavity, as studied with CPK-models, which could include planar, aromatic guests. Crystals obtained from benzene/ -heptane point to a 1 2 stoichiometry of 63 and benzene according to NMR-spectroscopic data. However, whether this is a molecular inclusion complex or just a clathrate is not yet known. 

Itraconazole (Sporanox , Janssen) is solubilized as a molecular inclusion complex using hydro-xypropyl- p-cyclodextrin. 

Regiospecific and Stereospecific Reactions in Molecular Inclusion Complexes of Steroids... 

Nonionic food grade emuslifiers/ water/ limonene/ethanol/ propyleneglycol Molecular inclusion complexes Starch... 

Accurate determination of the structures of molecular inclusion complexes and molecular assemblies has gained in importance in supramolecular chemistry and recently in crystal engineering. Detailed information about the nature of these weak intermolecular interactions is crucial in order to understand and further develop supramolecular systems and understand crystal growth and the properties of crystalline materials. Particularly accurate structural information can be gained in the solid state by single crystal X-ray crystallography. 

General cyclodextrin structure (e.g. for a-cyclodextrin, n=7) the glucose units form a bucket-like structure suitable for molecular inclusion complexation. 

This molecular inclusion complex now crystallizes as a unity in a known crystal lattice. 

Reineccius, T.A., Reineccius, G.A., Peppard, T.L., 2005. The effect of solvent interactions on alpha-, beta-, and gamma-cyclodextrin flavor molecular inclusion complexes. J. Agric. Food Chem. 53,388-392. 

For example, at molecular levels, micellization and molecular inclusion complexation represent some of the simplest approaches to fabricate matrix-type systems. 

However, when products were subjected to sensory evaluation, results indicate that the benefits of enhanced flavor retention achieved by the flavor/CD complexation could be mitigated by poor release from molecular-inclusion complexes during consumption (Reineccius et al., 2004). 

Determination of the accurate structures of molecular inclusion complexes and molecular assemblies gained a lot of importance in supramolecular chemistry. 

The neutral molecular inclusion complexes of the naturally occurring cyclodextrins (121) and the synthetic macrocyclic polyethers have been comprehensively reviewed recently (122) and are not reported. 

H. Rachmawati, C.A. Edityaningrum, and R. Mauludin, Molecular inclusion complex of curcumin-P-cyclodextrin nanoparticle to enhance curcumin skin permeability from hydrophilic matrix gel, AAPS PharmSaTech, 14 (4), 1303-1312,2013. 

Solid state investigations are of great importance in particular in case of studying calixarene and calix-type compounds due to their great ability to form molecular inclusion complexes, co-crystals and supramolecular assemblies. In CSD (Cambridge Structural Database [1]) over 6000 structures of calix-type compounds are deposited so far. Approximately one-third of the entries are organometallic compounds and two-thirds are classified as organic compounds. 

In 1,3-alternate conformation the benzene rings of calix[4]arene are perpendicular or almost perpendicular to the main plane of the molecule defined by the four methylene bridges. As a consequence, the inclusion of guest molecules into the host cavity is much more difficult compared to the cone conformation and as general rather co-crystals than molecular inclusion complexes are observed. One of the exceptions is an inclusion/additive complex of para-bromomethyl-dodecamethylcalix[4]arene with 1,2-dichloroethane where one molecule of guest is included in shallow cavity on one side of the host molecule while the second guest molecule forms an additive complex (Fig. 38.13a) [28]. 

Complex formation Formation of different types of complexes, such as charge transfer complex due to interaction between the analytes and the modified stationary phase or the formation of complexes between a metal ion and the donor molecule, having at least one pair of electrons or formation of molecular inclusion complex due to steric interactions have also been considered. There are no reports on TLC resolution of enantiomers of NSAIDs using this approach. 

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