Host Behavior of N,N′-Bis(9-phenyl-9-thioxanthenyl)ethylenediamine in the Presence of Aromatic and Aliphatic Five-Membered Heterocyclic Guests: Selectivity Correlations with Hirshfeld Surface Analyses

The crystalline compound N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine (1) was assessed for its host ability in the presence of eight five-membered ring heterocyclics, namely, saturated tetrahydrofuran, tetrahydrothiophene, and pyrrolidine, and aromatic equivalents furan, thiophene, and pyrrole and, additionally, imidazole and pyrazole. Host 1 clathrated all six mono-heteroatomic guests, while complexes were not formed with imidazole and pyrazole. Specifically designed guest/guest competition experiments revealed that 1 preferred both the saturated heterocyclics (relative to the aromatics) and the sulfur-containing guests (in both saturated and aromatic series) followed by oxygen and nitrogen (S > O > N). The affinity of the host for the saturated guests was explained by means of a consideration of the applicable host···guest interactions, obtained from single crystal diffraction analyses, where these guests were observed to experience a greater variety and number of these interaction types relative t...