TY  - JOUR
A1  - Ivanova, Svetlana
A1  - Köster, Eva
A1  - Holstein, Julian J.
A1  - Keller, Niklas
A1  - Clever, Guido H.
A1  - Bein, Thomas
A1  - Beuerle, Florian
T1  - Isoreticular crystallization of highly porous cubic covalent organic cage compounds
JF  - Angewandte Chemie International Edition
N2  - Modular frameworks featuring well-defined pore structures in microscale domains establish tailor-made porous materials. For open molecular solids however, maintaining long-range order after desolvation is inherently challenging, since packing is usually governed by only a few supramolecular interactions. Here we report on two series of nanocubes obtained by co-condensation of two different hexahydroxy tribenzotriquinacenes (TBTQs) and benzene-1,4-diboronic acids (BDBAs) with varying linear alkyl chains in 2,5-position. n-Butyl groups at the apical position of the TBTQ vertices yielded soluble model compounds, which were analyzed by mass spectrometry and NMR spectroscopy. In contrast, methyl-substituted cages spontaneously crystallized as isostructural and highly porous solids with BET surface areas and pore volumes of up to 3426 m\(^2\) g\(^{-1}\) and 1.84 cm\(^3\) g\(^{-1}\). Single crystal X-ray diffraction and sorption measurements revealed an intricate cubic arrangement of alternating micro- and mesopores in the range of 0.97–2.2 nm that are fine-tuned by the alkyl substituents at the BDBA linker.
KW  - organic chemistry
KW  - structure elucidation
KW  - boronateesters
KW  - cage compounds
KW  - dynamic covalent chemistry
KW  - porousmaterials
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256462
VL  - 60
IS  - 32
ER  - 
TY  - JOUR
A1  - Kirchner, Philipp H.
A1  - Schramm, Louis
A1  - Ivanova, Svetlana
A1  - Shoyama, Kazutaka
A1  - Würthner, Frank
A1  - Beuerle, Florian
T1  - A water-stable boronate ester cage
JF  - Journal of the American Chemical Society
N2  - The reversible condensation of catechols and boronic acids to boronate esters is a paradigm reaction in dynamic covalent chemistry. However, facile backward hydrolysis is detrimental for stability and has so far prevented applications for boronate-based materials. Here, we introduce cubic boronate ester cages 6 derived from hexahydroxy tribenzotriquinacenes and phenylene diboronic acids with ortho-t-butyl substituents. Due to steric shielding, dynamic exchange at the Lewis acidic boron sites is feasible only under acid or base catalysis but fully prevented at neutral conditions. For the first time, boronate ester cages 6 tolerate substantial amounts of water or alcohols both in solution and solid state. The unprecedented applicability of these materials under ambient and aqueous conditions is showcased by efficient encapsulation and on-demand release of β-carotene dyes and heterogeneous water oxidation catalysis after the encapsulation of ruthenium catalysts.
KW  - absorption
KW  - hydrocarbons
KW  - materials
KW  - organic compounds
KW  - stability
KW  - boronate esters
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-361245
SN  - 0002-7863
VL  - 146
IS  - 8
ER  -