Clathrate related compounds

Gnaim, J. M., Green, B. S., Aradyellin, R., Keehn, P. M., Improved preparation of the clathrate host compound triortho-thymotide and related trisalicylide derivatives. J. Org. Chem. 1991, 56, 4525-4529. 

Structural analysis of the 1 1 cocrystal, as well as [69] the structures of several related compounds Structures of the 2 1 piperazine and 1 1 piperidine [70] cocrystals, and comparison of these with the known clathrate structures Structures of 11 new cocrystals, and elucidation [71] of the amide-acid and amide-amide hydrogen bonding in relation to synthon assembly... 

Nishikiori. S. Ratcliffe, C.I. Ripmeester, J.A. " Cd NMR studies of Hofmann type clathrates and related compounds ... 

High Pressure Synthesis of Superconducting Silicon Clathrates and Related Compounds... 

Table 7.4 Superconductivity of silicon clathrates and related compounds...

Fig. 2. Classification/nomenclature of host—guest type inclusion compounds, definitions and relations (/) coordinative interaction, (2) lattice barrier interaction, (J) monomolecular shielding interaction (I) coordination-type inclusion compound (inclusion complex), (II) lattice-type inclusion compound (multimolecular/extramolecular inclusion compound, clathrate), (III) cavitate-type inclusion compound (monomolecular/intramolecular inclusion...

Not only hydroquinone, but also phenol and a number of related substances have been reported20,21 33,44 to form clathrate compounds of a similar type. But this class of substances proves to be... 

Nevertheless, as in many previous observations, the clathrate formation by dipolar host compounds could not have been predicted in advance. In fact, there are no channels in the crystal structures of hydrated moxnidazole hydrochloride (closely related species to furaltadone hydrochloride) and of hydrated furaltadone base (Fig. 13)37). Rather, the latter two structures are best described as solvates with the H20 molecules contained in local voids between adjacent moieties of the host. 

In contrast to carbon, which forms structures derived from both sp2 and sp3 bonds, silicon is unable to form sp2 related structures. Since one out of four sp3 bonds of a given atom is pointing out of the cage, the most stable fullerene-like structure in this case is a network of connected cages. This kind of network is realized in alkali metal doped silicon clathrate (19), which were identified to have a connected fullerene-like structure (20). In these compounds, Si polyhe-dra of 12 five-fold rings and 2 or 4 more six-fold rings share faces, and form a network of hollow cage structures, which can accommodate endohedral metal atoms. Recently, the clathrate compound (Na,Ba), has been synthesized and demonstrated a transition into a superconductor at 4 K (21). The electronic structure of these compounds is drastically different from that of sp3 Si solid (22). 

The compounds M(NH3)2Ni(CN)4 (M = Zn or Cd), which consist of two-dimensional polymeric sheets of tetracyanonickelate ions bridged by coordinating diamminemetal(II) cations, function as host lattices for clathration of small aromatic molecules such as thiophene, furan, pyrrole or pyridine IR studies indicate the presence of hydrogen bonding between the host lattice ammonia and the aromatic guest molecules.132,133 A crystal structure determination of the related clathrate Cd(en)Ni(CN)4(pyrrole)2 has been reported.134 Similarly, the complex Cd(py)2Ni(CN)4 consists of polymeric [Cd—Ni(CN)4] layers held together by Cd-bound pyridine.135... 

Some derivatives of 56 have been investigated because they are related to the widely used pyrethroid insecticides. Pure cyhalothric acid (70) forms H-bonded centrosymmetric dimers in the crystal125. Newly discovered clathrates with aromatic molecules may facilitate the separation of isomers126. The structures of the acid 71 and of its 2/1 inclusion compound with benzene have been determined126. 

The fact that liquid clathrates are thus liquids based on ionic compounds means that they are somewhat related in terms of their properties to ionic liquids (Section 13.4), but they are fundamentally a two or more component phase instead of a pure compound. A recent report has shown, however, that bmim... 

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