Host Ability of (+)-(2R,3R)‑1,1,4,4-Tetraphenylbutane-1,2,3,4-tetraol (TETROL) in the Presence of γ‑Butyrolactone‑, 2‑Pyrrolidone‑, and N‑Alkyl-substituted 2‑Pyrrolidones

In the present work, (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (TETROL) was assessed for its host ability in γ-butyrolactone (GBL), 2-pyrrolidone (NP), N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), and mixtures of these. These compounds are often present as mixtures in the synthesis of NMP and NEP. TETROL formed crystalline inclusion compounds with each compound, with the exception of GBL, which was not enclathrated. In mixed guests, TETROL was revealed to behave extremely selectively, especially when these mixtures were binary and equimolar in nature and had present GBL; GBL/NP, GBL/NMP and GBL/NEP furnished crystals with 93.8%, 84.8%, and 93.2% NP, NMP, and NEP, respectively. The ternary equimolar mixture, GBL/NP/NEP, also saw TETROL absorb significant amounts of NEP (89.9%). In these particular cases, TETROL may therefore serve as an ideal separatory agent for such mixtures. Data from single crystal X-ray diffraction (SCXRD) analyses revealed the H-bonding motifs present in all of these crystal structures . Hirshfeld surfaces and guest packing in the voids of the complexes were, furthermore, analyzed, and thermal experiments were also carried out; the peak temperature of the endotherm for the guest release process for the NMP-containing complex (the favored guest) was greater than those in the remaining two complexes.