TY  - JOUR
A1  - Schäfer, Natalie
A1  - Bühler, Michael
A1  - Heyer, Lisa
A1  - Röhr, Merle I. S.
A1  - Beuerle, Florian
T1  - Endohedral Hydrogen Bonding Templates the Formation of a Highly Strained Covalent Organic Cage Compound
JF  - Chemistry—A European Journal
N2  - A highly strained covalent organic cage compound was synthesized from hexahydroxy tribenzotriquinacene (TBTQ) and a meta-terphenyl-based diboronic acid with an additional benzoic acid substituent in 2’-position. Usually, a 120° bite angle in the unsubstituted ditopic linker favors the formation of a [4+6] cage assembly. Here, the introduction of the benzoic acid group is shown to lead to a perfectly preorganized circular hydrogen-bonding array in the cavity of a trigonal-bipyramidal [2+3] cage, which energetically overcompensates the additional strain energy caused by the larger mismatch in bite angles for the smaller assembly. The strained cage compound was analyzed by mass spectrometry and \(^{1}\)H, \(^{13}\)C and DOSY NMR spectroscopy. DFT calculations revealed the energetic contribution of the hydrogen-bonding template to the cage stability. Furthermore, molecular dynamics simulations on early intermediates indicate an additional kinetic effect, as hydrogen bonding also preorganizes and rigidifies small oligomers to facilitate the exclusive formation of smaller and more strained macrocycles and cages.
KW  - boronate esters
KW  - hydrogen bonding
KW  - dynamic covalent chemistry
KW  - density functional calculations
KW  - cage compounds
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256762
VL  - 27
IS  - 19
ER  -