Inclusion compounds history

The history of inclusion compounds (1,2) dates back to 1823 when Michael Faraday reported the preparation of the clathrate hydrate of chlorine. Other early observations include the preparation of graphite intercalates in 1841, the 3-hydroquinone H2S clathrate in 1849, the choleic acids in 1885, the cyclodextrin inclusion compounds in 1891, and the Hofmann s clathrate in 1897. Later milestones of the development of inclusion compounds refer to the tri-o-thymotide benzene inclusion compound in 1914, phenol clathrates in 1935, and urea adducts in 1940. 

Much interest has centred on the branch of cyclophanes known as calixarenes. They are polyphenol systems that can act as hosts in the formation of inclusion compounds, where a small guest molecule resides completely in a cavity within a single host they are cone-shaped cavitands . Several accounts have appeared of their history. The discovery by Baeyer of a formaldehyde/phenol resin led to Bakelite and to the work of A. Zincke and E. Ziegler, who gave to the first oligomer a tetrameric structure of a calix[4]arene. Later syntheses by Gutsche (1978) led to calixarenes with 4, 6 or 8 phenol residues.107-109... 

The cyclodextrins (cycloamyloses) are torus-shaped molecules that can form crystalline inclusion compounds, recently attracting much attention as enzyme-site models. Their history has been seen in three phases. From 1891 to 1935 they were known as natural products, but with no recognition of their exact chemical structure. This recognition emerged in the second period, to about 1970, when most of their characteristics were also elucidated. The period from 1970 to the present has seen considerable research into their industrial use and production.239 Their inclusion compounds or complexes have found employment in such diverse fields as explosives, insecticides, pharmaceutical products, rust-prevention agents, and even baking powder. 

The chemistry of inclusion compounds has a long history Confirmed accounts on the preparation of such chemical species date back to the beginning of the nineteenth century. At that early time Davy, and shortly afterwards Faraday, reported of a chlorine clathrate hydrate... 

The chemistry of inclusion compounds also looks back on a lively history There are many events of significance in the area of inclusion chemistry till the middle of the twentieth century including the discovery of new inclusion compounds and hosts (Fig. 1), among them the graphite intercalates, the P-quinol and cyclodextrin inclusion compounds, the Hofmann-type clathrates as well as the inclusion compounds of tri-o-thymotide, Dianin s compound, the choleic acids, of phenols, of urea and others specified in comprehensive monographs... 

This article reviews the history and synthesis of tetraphenylene (tetrabenzo[n, c, e, g] cyclooctatetraene), its ability to enclathrate a wide range of guest species, the structural characteristics of the resulting class of clathrate inclusion compounds, and synthetic approaches to the preparation of tetraphenylene derivatives which may serve as potential host systems. 

The history of inclusion compounds dates back to the early nineteenth century, with Humphrey Davy s discovery of chlorine hydrate, but the field of inclusion phenomena, or host-guest chemistry, a subfield of su-pramolecular chemistry, is growing dramatically, particularly in the last 10 years. This can be seen at a glance in Fig. 1, which shows the number of abstracts appearing in Chemical Abstracts under the term clathrate" and inclusion compound (Fig. la) and supramolecular chemistry (Fig. lb). 

DTU contains two component moieties which have a famous history in the field of inclusion compounds, urea [6] and triphenylme thane [7]. It is perhaps therefore somewhat surprising that the capacity of DTU to function as a host has not been previously studied. As described below, however, the complexes formed by DTU are unique and entirely different from those formed by either of its component moieties. 

The history of crystalline gas adsorbents is old and starts with the mineral zeolite. Nowadays, there are successful synthetic techniques for the production of zeolites and zeotypes with controlled diameter pores. Moreover, processes able to produce porosity in pure organic and metal-organic skeletons have been developed. Typical compounds suitable for the topics of this chapter are shown in Fig. 3.4.6. They possess inner accessible spaces for gaseous guests to generate a gas inclusion state... 

Studies on starch demonstrate that starch will include aroma compounds the extent of inclusion will depend upon the starch (proportion of amylose to amylopectin), its processing history, and the aroma compound. Hau et al. [19] have presented a view of the extent of interactions one observes via static methods (measure of chemical interactions) between selected aroma compounds and starch (Figure 6.6). It is clear that the amount of interaction is quite significant for some compounds (nearly 80% of the hexanol is bound). The interaction is both compound and time dependent (although most compounds reached a plateau in binding after only 1 hr). It is postulated that free amylose forms a helical structure that has hydrophobic areas that will include certain aroma compounds. It should be noted that this research... 

European museums, particularly in herbaria. The use of arsenic and mercury compounds in natural history technology and taxidermy has actually been actively encouraged over the past century with the inclusion of countless recipes for fixatives based on mercuric chloride, arsenious oxide and other compounds. 

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