Guest toluene xylenes

Many calixarenes form complexes in the solid state, this property having been observed even before the structure of compounds was established. Among the simple ca-lix[n]arenes, for example, / >-rer/-butylcalix[4]arene forms complexes with chloroform, benzene, toluene, xylene, nitrobenzene, nitromethane, acetonitrile, and many others, while /r-rer/-butylcalix[5]arene complexes were studied with lower alcohols, ethyl acetate, toluene, and tetraline. More flexible / -terr-butylcalix[6]arene was found to form complexes with acetonitrile and / -rerr-butylcalix[8]arene with chloroform. The tenacity with which the guest molecule is held by the calixarene hosts varies widely with the size of macrocycle. Whereas tetramers to hex-... 

Figure 12 Cross-sections of CA host channels sliced parallel to the direction of the channel (carbon and hydrogen atoms are represented by gray and white, respectively) with arrays of included guest molecules (hydrogen atoms are omitted for clarity, and carbon and oxygen atoms are represented by open and filled circles, respectively), (a) toluene, (b) w-propylbenzene, (c) n-butylbenzene, (d) w-hexylbenzene, (e) p-xylene, and (f) methyl methacrylate.

Trithiocyanuric acid (TCA) and 4,4 -bipyridyl (BP) form hydrogen-bonded co-crystals with aromatic compounds such as benzene, toluene, /7-xylene and anthracene. The TCA-BP co-crystal is composed of cavities formed by the N-H - N hydrogen bonds between the two molecules, and the three-dimensional structure contains channels of approximately 10 A where aromatic molecules are accommodated. The molar ratios of TCA, BP and the aromatic compound in the co-crystals are 2 1 1 or 2 1 0.5. Benzene, toluene and /7-xylene are removed from the channels around 190, 183 and 170 °C respectively, and these aromatic guests can be reintroduced into the empty channels of the apo-hosts. The apo-hosts with empty channels have reasonable thermal stability and exhibit shape selectivity in that the empty channels accommodate /7-xylene but not m- or o-xylene or mesitylene. 

TGA of the toluene co-crystal 2 showed a mass loss of 14.8% at 183 °C. The host crystals with the empty channels were soaked in toluene for 36 hours and then subjected to TGA. These crystals showed a mass loss of 9.2% at 166 °C, a behaviour similar to that of the benzene co-crystal, 1. TGA of the /7-xylene cocrystal, 5, showed a mass loss (12.2%) due to the removal of the aromatic guest around 167 °C. After reintroduction of /7-xylene in the channels, the mass loss occurred around 139 °C, but the magnitude of mass loss was smaller... 

Earlier, we had reported the exchange of benzene with benzene-dg in the channels of 6 without the destraction of crystallinity. We have extended this study to other guests like toluene, m-xylene, undecane, benzyl alcohol, 2,6-di-ten-butylphenol and ( )-l-phenylethanol."" Cell constants determined by X-ray powder diffraction after exchange were close to the original cell constants. Optical micrographs showed that there was no dissolution and reformation of the crystals during the period of exchange. 

Out of the five solvents tested (CD2CI2, CDCI3, C6Dg, toluene-[Pg.122]

The host Ni(4-mepy)4(NCS)2 If forms isomorphous 1 1 inclusion compounds with many monocyclic aromatic guests. In continuing attempts to determine the basis for the selectivity shown by towards pairs of such guests, distribution data between solid and liquid phases were reported for seven ternary systems at room temperature. These consist of -xylene, and each of the following in turn -bromotoluene, -chlorotoluene, -fluorotoluene, -dichlorobenzene, 4-meth-ylpyridine and benzene, as well as the system I — -chloro-toluene— -dichlorobenzene, The results, as well as those already published, were reviewed. 

Recently three-dimensional metal complex hosts have been developed from the two-dimensional Hofmann type host lattices, M(NH3)2Ni(CN)4, by replacing the ammonia groups by bidentate ligands, with the aim of enlarging the range of guest molecules which can be accommodated in the host lattices [1-5]. In a previous study Mathey et al. reported the preparation of the Ni(4,4 -bipyridyl)Ni(CN)4 host lattice and its benzene, xylene, naphthalene and anthracene clathrates [5]. We have extended this study and prepared M(4,4 -bipyridyl)Ni(CN)4-2G (M = Ni or Cd G = dioxane, toluene, aniline or iV,AT-dimethylaniline) clathrates for the first time. In this study an IR spectroscopic study of the M(4,4 -bipy)Ni(CN)4 -MG compounds (where M = Ni or Cd, G = dioxane, benzene, toluene, aniline or iV,AT-dimethylaniline, n=0-2) (abbreviated henceforth as M-Ni-bipy-G) are reported. Additional information is obtained from the laser-Raman spectrum of the Cd-Ni-bipy complex. We also recorded the powder X-ray diffraction patterns of the M-Ni-bipy complexes. 

Template effect of guest solvent molecules such as benzene, toluene, and para-xylene has... 

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