Isoretikuläre Kristallisation von hochporösen kubischen kovalentorganischen Käfigverbindungen**

Abstract

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 1.82 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. File list (8) download file view on ChemRxiv 2021_02_Ivanova_manuscript_ChemRxiv.pdf (3.17 MiB) download file view on ChemRxiv 2021_02_Ivanova_SI_ChemRxiv.pdf (9.00 MiB) download file view on ChemRxiv ek20_sq-finalcif.cif (3.79 MiB) download file view on ChemRxiv ek27_sq-finalcif.cif (2.93 MiB) download file view on ChemRxiv si30_sq-finalcif.cif (1.64 MiB) download file view on ChemRxiv 2Me_channel.mp4 (2.20 MiB) download file view on ChemRxiv 2Et_channel.mp4 (2.33 MiB) download file view on ChemRxiv 2nBu_channel.mp4 (2.64 MiB)

Solvent‐Controlled Quadruple Catenation of Giant Chiral [8+12] Salicylimine Cubes Driven by Weak Hydrogen Bonding

“…This packing motif leads to a highly porous structure with two distinct pores in the solid state (Figure 4g) and a calculated virtual porosity of 3867 m 2 g −1 (program CrystalExplorer, isovalue: 0.0003 au) [29] . However, it has recently been shown, that during desolvation of such crystals, the very weak and non‐directing interactions leads to a dramatic loss of crystallinity and thus porosity, which can be prevented by having smaller alkyl chains in the cage peripheries [30] . Creating highly porous molecular cages [31] was not the objectives of this study rather than getting a deeper insight in chiral self‐sorting [23, 32] …”

Porous Organic Compounds – Small Pores on the Rise

“…The bulk of work so far described imine condensation reactions for POC self‐assembly but boronate ester formation, among others, is also a powerful tool to generate porous organic materials [9,21b] . The group of Beuerle contributed several giant molecular cubes, assembled from catechol‐functionalized tribenzotriquinacenes and 1,4‐phenylene diboronic acids, which were synthesized in one‐pot procedures by crosslinking 20 individual components through a dynamic covalent approach [4a,6a,21c] . Investigations on the self‐sorting of ternary mixtures containing two competitive boronic acids were reported later [21b] .…”

Controlled Formation of Porous 2D Lattices from C3‐symmetric Ph6−Me‐Tribenzotriquinacene‐OAc3

“…Tribenzotriquinacenes (TBTQs) have recently come into focus as model compounds for highly curved, defective graphene structures [16] and are also being investigated as building blocks for highly porous 3D organic frameworks. [17,18] TBTQs can be functionalized in different positions leading to derivatives with functional moieties for sensing, covalent assembly, or molecular recognition. [19][20][21][22] The assembly of simple TBTQs has been studied both in crystals [23][24][25] and on surfaces.…”