N,N′-Bis(9-phenyl-9-thioxanthenyl)ethylenediamine: Highly Selective Host Behavior in the Presence of Xylene and Ethylbenzene Guest Mixtures

Abstract

Host compound N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine formed 1:1 host:guest complexes with o- and p-xylene, and ethylbenzene, when recrystallized from them. The meta-isomer was not included. Competition experiments using equimolar binary and ternary mixtures of the three xylenes demonstrated that this host is markedly selective for p-xylene (≥94% on both a milligram- and gram-scale), while 68% of this guest was extracted from an equimolar quaternary mixture of the three xylenes and ethylbenzene. This selectivity was also evident when guest ratios in binary mixtures containing p-xylene were varied. The observed high affinity for the para-isomer was explained using single crystal X-ray diffraction, Hirshfeld surface analysis and thermoanalytical experiments. Furthermore, the host was subjected to gas phase guests in order to establish whether the ability existed for complexation of these guests from the solid state.