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7952233 
Journal Article 
Synthesis and assessment of compounds trans-N,N-bis(9-phenyl-9-xanthenyl)cyclohexane-1,4-diamine and trans-N,N-bis(9-phenyl-9-thioxanthenyl)cyclohexane-1,4-diamine as hosts for potential xylene and ethylbenzene guests 
Barton, B; Jooste, DV; Hosten, EC 
2019 
Yes 
Journal of Inclusion Phenomena and Macrocyclic Chemistry
ISSN: 1388-3127
EISSN: 1573-1111 
93 
3-4 
333-346 
English 
WOS:000461386000019 
In this work, two novel compounds, trans-N,N′-bis(9-phenyl-9-xanthenyl)cyclohexane-1,4-diamine 1 and trans-N,N′-bis(9-phenyl-9-thioxanthenyl)cyclohexane-1,4-diamine 2, were designed and successfully synthesized in our laboratories, and assessed for their host potential in the presence of potential xylene (Xy) isomer and ethylbenzene (EB) guests. Host 1 successfully formed complexes with all four of o-Xy, m-Xy, p-Xy and EB, while 2 only clathrated p-Xy and EB. Equimolar guest/guest competition experiments showed that hosts 1 and 2 possess very similar selectivities for these guests [p-Xy (73.9%) > EB (13.0%) > m-Xy (8.1%) > o-Xy (5.0%) and p-Xy (71.3%) > EB (20.2%) > m-Xy (6.0%) > o-Xy (2.5%) for 1 and 2, respectively]. Single crystal diffraction analyses revealed striking geometry changes for the sulfur host analogue: while the tricyclic fused ring system of the oxygen host remained planar when guest was absent or present, this fused system of the sulfur analogue experienced a dramatic geometry change from buckled (in the absence of guest) to planar (in guest presence). This observation explained the selectivity similarities of both hosts in the presence of these guests. Additionally, the relative thermal stabilities of the four complexes with host 1 were assessed by employing thermal analyses, and the results of these correlated exactly with the selectivity order, since the onset temperature of the guest release processes (T on ) was in the order p-Xy (88.0 °C) > EB (70.9 °C) > m-Xy (59.7 °C) > o-Xy (46.2 °C). T on values also explained the significant preference of host 2 for p-Xy (115.5 °C) relative to EB (76.6 °C), respectively. 2019, Springer Nature B.V. 
Xylene; Ethylbenzene; Host-guest chemistry; Supramolecular chemistry; Xanthenyl systems