TY  - JOUR
A1  - Riad, Noura M.
A1  - Zlotos, Darius P.
A1  - Holzgrabe, Ulrike
T1  - Crystal structure of 5,11-dihydropyrido[2,3-b][1,4]benzodiazepin-6-one.
JF  - Acta Crystallographica Section E Crystallographic Communications
N2  - The title compound, C\(_{12}\)H\(_{9}\)N\(_{3}\)O, is an inter­mediate in the synthesis of the muscarinic M2 receptor antagonist AFDX-384. The seven-membered ring adopts a boat conformation and the dihedral angle between the planes of the aromatic rings is 41.51 (9)°. In the crystal, mol­ecules are linked into [001] chains of alternating inversion dimers formed by pairs of N-H・・・O hydrogen bonds and pairs of N-H・・・N hydrogen bonds. In both cases, R\(_{2}\)\(^{2}\)(8) loops are generated.
KW  - crystal structure
KW  - pyridobenzodiazepine
KW  - boat conformation
KW  - hydrogen bonding
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149627
VL  - E71
ER  - 
TY  - JOUR
A1  - Verma, Pramod Kumar
A1  - Steinbacher, Andreas
A1  - Schmiedel, Alexander
A1  - Nuernberger, Patrick
A1  - Brixner, Tobias
T1  - Excited-state intramolecular proton transfer of 2-acetylindan-1,3-dione studied by ultrafast absorption and fluorescence spectroscopy
JF  - Structural Dynamics
N2  - We employ transient absorption from the deep-UV to the visible region and fluorescence upconversion to investigate the photoinduced excited-state intramolecular proton-transfer dynamics in a biologically relevant drug molecule, 2-acetylindan-1,3-dione. The molecule is a ß-diketone which in the electronic ground state exists as exocyclic enol with an intramolecular H-bond. Upon electronic excitation at 300 nm, the first excited state of the exocyclic enol is initially populated, followed by ultrafast proton transfer (≈160 fs) to form the vibrationally hot endocyclic enol. Subsequently, solvent-induced vibrational relaxation takes place (≈10 ps) followed by decay (≈390 ps) to the corresponding ground state.
KW  - time resolved spectroscopy
KW  - ground states
KW  - fluorescence spectra
KW  - absorption spectra
KW  - ultraviolet light
KW  - hydrogen bonding
KW  - excited states
KW  - reaction mechanisms
KW  - fluorescence
KW  - solvents
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181301
VL  - 3
ER  - 
TY  - JOUR
A1  - Kraft, Andreas
A1  - Stangl, Johannes
A1  - Krause, Ana-Maria
A1  - Müller-Buschbaum, Klaus
A1  - Beuerle, Florian
T1  - Supramolecular frameworks based on [60]fullerene hexakisadducts
JF  - Beilstein Journal of Organic Chemistry
N2  - [60]Fullerene hexakisadducts possessing 12 carboxylic acid side chains form crystalline hydrogen-bonding frameworks in the solid state. Depending on the length of the linker between the reactive sites and the malonate units, the distance of the [60]fullerene nodes and thereby the spacing of the frameworks can be controlled and for the most elongated derivative, continuous channels are obtained within the structure. Stability, structural integrity and porosity of the material were investigated by powder X-ray diffraction, thermogravimetry and sorption measurements.
KW  - chemistry
KW  - fullerenes
KW  - hexakisadducts
KW  - hydrogen bonding
KW  - porous materials
KW  - structure elucidation
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171996
VL  - 13
ER  - 
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  -