Inclusion compounds stoichiometry

Formation of Inclusion Compounds, Host-Guest Stoichiometries 56... 

Table 1. Clathrate inclusion compounds of I stoichiometries and thermal stability characterization...

On the other hand, since the angular derivative 19, whose constitution is characterized by two quasi-isolated hydroxynaphthalenecarboxylic acid subunits and whose structural analogy to a pair of scissors is removed for the most part, also yields an inclusion compound with dimethylformamide with strict stoichiometry of 1 237), and only and exclusively this one (Table 3), it is obvious that the free salicylic acid unit might be the decisive factor for the preferred binding of dimethylformamide of this class of compounds. 

Considering this variety of crystalline inclusion compounds, 26 is close to 1 (cf. Table 1) and like 1, the stoichiometries (host guest) found for the different aggregates of 26 largely correspond to the expected ratios. Thermal stabilities in most cases are relatively high. 

Examination of the steric relations in these complexes (cf. Fig. 30) suggests that the more voluminous branched alcohols cannot follow the same principle. Indeed, in the 2-butanol and also in the t-butanol inclusion compound, a different ring system is built (Fig. 17b and type I in Fig. 19). While the short-chain alcohols form twelve-membered H-bond loops, the branched butyl alcohols are embedded into a ten-membered asymmetric loop. The stoichiometry of the asymmetric unit also changes from 1 2 (host guest) ratio to 1 1. The so-built ring system of homodromic H-bonds still contains a mirror-related pair of hosts 1, but comprises only one guest molecule. 

A more deviating stoichiometry is found in the case of the inclusion compound of / with /-propanol 77 >. Here the assistance of two independent host molecules is required and results in a 2 1 stoichiometry. Nevertheless, even this unusual host guest ratio gives rise to a similar H-bond pattern (Fig. 18a and type lib in Fig. 19) as found for the inclusions of 1 with simpler alcohols (cf. Fig. 17a), namely the 12-membered ring system. Now, another interesting fact arises, signalling the flexibility of host 1 in its inclusion behavior. This is the formation of host dimers through H-bonds to ensure clathration. 

In 1979 the bieyclic diol exo-2,ejco-6-dihydroxy-2,6-dimethylbicyclo[3.3.1]nonane (i) was prepared and observed to co-crystallise with various solvents, including ethyl acetate, chloroform, toluene, dioxane, and acetone. A crystal structure determination of the ethyl acetate compound revealed the occurrence of a helical canal host structure, containing ethyl acetate as guest (with 3 1 diol ethyl acetate stoichiometry), and that spontaneous resolution had occurred on crystallisation of the multimolecular inclusion compound 6>. 

There are many other types of inclusion compounds of undefined stoichiometry in which the guest molecules are confined in tunnels and cages... 

MacNicol and Wilson 15) synthesized a series of compounds (20) called hexa-hosts . Such hexa-substituted benzenes can, on crystallization from suitable solvents, from a wide range of inclusion compounds. When Y = SPh, for example, a crystalline complex with CC14 was isolated having a host-guest stoichiometry of 1 2. The CC14 is... 

Inclusion compounds are crystalline hosts that have channels in which a guest molecule may reside, e.g., templated urea. Non-stoichiometric ICs are typically formed. Clathrates, or cage compounds, are a special type of inclusion compound that possess fully enclosed voids. Integral stoichiometries for their ICs are expected. For example, hydroquinone (1) forms a hydrogen-bonded trimer that can confine a... 

The spectroscopic studies and elemental analysis revealed that stoichiometry of the inclusion compound in water is identical to its stoichiometry in solid state. The mono[6-deoxy-6-(2-butenedinitrile-2,3-dimercapto sodium salt)]-/3-CD can also be encapsulated [(77 -CsHs)Mn(CO)3]. Upon irradiation of the inclusion compound in DMF solution, an interesting intramolecular photosubstitution resulting in the formation of a very stable self-included compound was observed (Figure 11). 

Recently, a clathrate system was announced in which the host entraps mixed guests, and the stoichiometry is controlled by the relative concentrations of the guests in the starting mixture. The host, rra i.v-9,10-dihydroxy-9,10-Z /.s (/ ferr-butylphenyl)-9,10-dihydroanthracene (N) forms inclusion compounds with dimethylformanide (A) and dimethylsulfoxide (B) of the type H nA (4-n)B, such that n varies from 0 to The results of competition experiments are given in Fig. 2, which shows that the stoichiometry of the inclusion compounds varies in discrete steps, giving rise to five distinct compounds H 4A, H 3A B, H 2A 2B, H A 3B, and H 4B. 

The CD -ferrocene complexes were characterized by elemental analysis, IR, UV, and H-NMR spectra. Stoichiometries were determined by elemental analysis, and especially the iron content measured by atomic absorption analysis and from the H-NMR spectra, which show all the complexes obtained here are stoichiometric compounds and have definite ratios of CD/guest depending on the combinations of host and guest. Table I shows the results of the preparation of inclusion compounds of CDs with ferrocene. 3 CD formed 1 1 inclusion compounds with ferrocene. 

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