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Synthesis and Dimerization Properties of Cup‐ and Bowl‐shaped Cyclic Trilactams
Author(s) -
Sartyoungkul Sitanan,
Yakiyama Yumi,
Sakurai Hidehiro
Publication year - 2020
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202000140
Subject(s) - chemistry , dimer , hydrogen bond , crystallography , solvent , amide , solubility , proton nmr , crystal structure , polymer chemistry , stereochemistry , molecule , organic chemistry
Two chiral trilactams, cup‐shaped (−)‐ 1 and bowl‐shaped (−)‐ 2 , were synthesized. Single crystal X‐ray analysis revealed that (−)‐ 1 formed dimer structure by the formation of three NH⋅⋅⋅O type complementary hydrogen bonds at three amide moieties. The equilibrium constant ( K eq ) and kinetic parameters ▵ H ° and ▵ S ° of the dimer formation phenomenon of (−)‐ 1 were determined by variable temperature proton NMR. Further binding energy calculation on both (−)‐ 1 and (−)‐ 2 dimers confirmed the more favourable formation of (−)‐ 1 dimer than (−)‐ 2 dimer, explaining the significant solubility difference of the two against the less polar solvent, such as CHCl 3 . Trilactam (−)‐ 1 afforded coordination polymer by complexation with Zn 2+ , keeping the capsule‐like structure.