Crystal structure and Hirshfeld surface analysis of 3-cyano-phenyl-boronic acid.

In the title compound, C7H6BNO2, the mean plane of the -B(OH)2 group is twisted by 21.28 (6)° relative to the cyano-phenyl ring mean plane. In the crystal, mol-ecules are linked by O-H⋯O and O-H⋯N hydrogen bonds, forming chains propagating along the [101] direction. Offset π-π and B⋯π stacking inter-actions link the chains, forming a three-dimensional network. Hirshfeld surface analysis shows that van der Waals inter-actions constitute a further major contribution to the inter-molecular inter-actions, with H⋯H contacts accounting for 25.8% of the surface.

Supramolecular arrangement and photophysical properties of a dinuclear cyanophenylboronic acid ester.

Boronic esters are useful building blocks for crystal engineering and the generation of supramolecular architectures, including macrocycles, cages and polymers (one-, two- and three-dimensional), with potential utility in diverse fields such as separation, storage and luminescent materials. The novel dinuclear cyanophenylboronic ester described herein, namely 4,4'-(2,4,8,10-tetraoxa-3,9-diboraspiro[5.5]undecane-3,9-diyl)dibenzonitrile, C19H16B2N2O4, was prepared by condensation of 4-cyanophenylboronic acid and pentaerythritol and fully characterized by elemental analysis, IR and NMR (1H and 11B) spectroscopy, single-crystal X-ray diffraction analysis and TG-DSC (thermogravimetry-differential scanning calorimetry) studies. In addition, the photophysical properties were examined in solution and in the solid state by UV-Vis and fluorescence spectroscopies. Density functional theory (DFT) calculations with ethanol as solvent reproduced reasonably well the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) of the title compound. Hirshfeld surface and fingerprint plot analyses are presented to illustrate the supramolecular connectivity in the solid state.