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  - 
TY  - JOUR
A1  - Röhr, Merle I. S.
T1  - New theoretical methods for the exploration of functional landscapes
JF  - International Journal of Quantum Chemistry
N2  - Molecular functionality can be often directly attributed to given properties of the electronic wavefunction. Analogous to the potential energy surface, these properties can be represented as a function of the nuclear coordinates, giving rise to molecular “functional landscapes.” However, so far there has been no possibility for their systematic investigation. This perspective aims to discuss the development of new theoretical methods based on the multistate extension of the metadynamics approach, employing electronic collective variables. This emerging methodology allows to explore functional landscapes and to gain a deeper understanding of the structure–function relation in molecules and complex molecular systems in the ground and excited electronic state.
KW  - structure–function relation
KW  - electronic collective variables
KW  - electronic wavefunction
KW  - metadynamics
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257682
VL  - 121
IS  - 24
ER  -