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Halogen Bonding Molecular Capsules
Author(s) -
Dumele Oliver,
Trapp Nils,
Diederich François
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201502960
Subject(s) - chemistry , supramolecular chemistry , halogen bond , halogen , solvent , denticity , calixarene , crystallography , benzene , hydrogen bond , molecule , crystal structure , organic chemistry , alkyl
Molecular capsules based solely on the interaction of halogen bonding (XB) are presented along with their host–guest binding properties in solution. The first example of a well‐defined four‐point XB supramolecular system is realized by decorating resorcin[4]arene cavitands with polarized halogen atoms for dimerization with tetra(4‐pyridyl) resorcin[4]arene cavitands. NMR binding data for the F, Cl, Br, and I cavitands as the XB donor show association constants ( K a ) of up to 5370 M −1 (Δ G 283 K =−4.85 kcal mol −1 , for I), even in XB‐competitive solvent, such as deuterated benzene/acetone/methanol (70:30:1) at 283 K, where comparable monodentate model systems show no association. The XB capsular geometry is evidenced by two‐dimensional HOESY NMR, and the thermodynamic profile shows that capsule formation is enthalpically driven. Either 1,4‐dioxane or 1,4‐dithiane are encapsulated within each of the two separate cavities within the XB capsule, with of up to K a =9.0 10 8 M −2 (Δ G 283 K =−11.6 kcal mol −1 ).