Nonlinear effect of two remembered guests in their mixtures on the host memory for guest inclusion and release
Selective memory for volatile guests after their inclusion and removal is a smart property of calixarenes, which are capable to form metastable polymorphs. This property is practically unpredictable, particularly for guest mixtures. In the present work, the mutual influence of the two guests in their binary mixture on this effect for tert-butylcalixarene was studied. The first example was found for an ability of two guests, benzene and tetrachloromethane, which can be remembered separately in binary host–guest systems, to erase the host memory to each of them forming a ternary clathrate with a much higher thermal stability than corresponding binary clathrates. Prepared mixed inclusion compounds perform a unique ability for fractional guest release on the separate steps of clathrate decomposition, which may be used for separation of pure volatile compounds from their mixtures. The clathrates were characterized by TG–DSC method combined with mass-spectrometric analysis of the evolved guest vapors and by X-ray powder diffractometry.
KeywordsCalixarene Inclusion compounds Clathrate Simultaneous thermal analysis Thermogravimetry Host memory
The work was supported by the Russian Government Program of Competitive Growth of Kazan Federal University (KFU) and by RFBR, Grant No. 14-03-01007. Equipment of the Federal Center of Shared Equipment of KFU was used in this work.
- 5.Safina GD, Gavrilova OM, Ziganshin MA, Stoikov II, Antipin IS, Gorbatchuk VV. Molecular recognition of chloroform by divergent polymorphic transitions in tert-butylthiacalixarene tetrasubstituted with N-(2-hydroxyethyl)carbamoylmethoxy groups in a lower rim. Mendeleev Commun. 2011;21:291–2.CrossRefGoogle Scholar
- 9.Barbour LJ. Crystal porosity and the burden of proof. Chem Commun. 2006;1163–68.Google Scholar
- 10.Atwood JL, Barbour LJ, Jerga A. Polymorphism of pure p-tert-butylcalixarene: conclusive identification of the phase obtained by desolvation. Chem Commun (Camb). 2002;2952–3.Google Scholar
- 12.Bernstein J. Polymorphism in molecular crystals. Oxford: Clarendon press; 2002.Google Scholar
- 15.Armarego WLF, Chai CLL. Purification of laboratory chemicals. Boston: Butterworth-Heinemann; 2009.Google Scholar
- 18.Hirata M, Ohe S, Nagahama K. Computer aided data book of vapor-liquid equilibria. New York: Elsevier; 1975.Google Scholar