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.