Self-Assembly and Exfoliation of a Molecular Solid Based on Cooperative B–N and Hydrogen Bonds

Abstract

Herein we report that 4-pyridinylboronic acid (1) in the solid state self-assembles into tetrameric macrocycles via B–N bond formation. The tetramers are linked via O–H···O bonds resulting in a material that can be exfoliated via sonication to give thinner sheets as we demonstrate via Fourier transform infrared spectroscopy, transmission electron microscopy, selected area electron diffraction, and atomic force microscopy experiments. For comparison, the structure of the related compound 4-(pyridin-4-yl) phenylboronic acid (2) is also discussed.

Semiconductor Cocrystals Based on Boron: Generated Electrical Response with π-Rich Aromatic Molecules

“…The cocrystal approach allows establishing persistent face-to-face and face-to-edge π-stacking. We envisage the future design of boron-based semiconductor cocrystals with included π-rich guests in related noncovalent framework materials. − …”

Adaptisorption of Nonporous Polymer Crystals

“…Herein, we report a model system that establishes adaptisorption for nonporous polymers, which is based on the combination of two components: the making and breaking of dative B−N bonds and the host‐guest (H−G) binding between naphthalene diimide ( NDI , Figure 1a) and 1,5‐dinaphtho[38]crown‐10 ( DN38C10 , Figure 1b). On the one hand, dative B−N bonds, capable of (1) being highly dynamic in solution, (2) exhibiting high stability in the solid state, and (3) featuring tunable bonding free energy (Δ G° ), [21–28] have been utilized (Figure 1c) as linkages to form the polymer BNP‐1 , prepared from the bispyridyl NDIN 2 and bisboronate BB 2 , as the sorbent [29] . On the other hand, the H−G binding units have been chosen as the recognition components because of (1) their high binding free energy that allows them to capture molecules, (2) the stimulus‐responsive binding free energy for trapping and releasing molecules, and (3) the high stability of the isolated crystals associated with mechanically interlocked components [30–39] .…”

Zwitterionic Systems Obtained by Condensation of Heteroaryl‐Boronic Acids and Rhodizonic Acid

“…[32] This is also in keeping with our investigation of the supramolecular assembly and solid-state properties of 4pyridinylboronic and of 4-(pyridine-4-yl)phenylboronic acid. [33] The initial purpose was the exploration of the possibility of obtaining multi-component crystals with boronic acid derivatives and rhodizonic acid as parent compounds, also in view of the well-established stability and versatility in the formation of heterodimers of the kind boronic acid/carboxylic acid and boronic acid/carboxylate. [34,35] Unexpectedly, however, the cocrystallization attempts rather than yielding co-crystals opened the door to the preparation of four novel building blocks obtained through a condensation reaction between rhodizonic acid and 4-pyridinylboronic acid (4-pyBA) and pyrimidine-5-boronic (pyrBA) acid, respectively.…”