2-Phenylnaphtho[1,8-de][1,3,2]diazaborinane

The title compound, C16H13BN2, is one compound in a series of diazaborinanes featuring substitution at the 1, 2 and 3 positions in the nitrogen–boron heterocycle. The title compound is slightly distorted from planarity, with a dihedral angle of 9.0 (5)° between the mean planes of the naphthalene system and the benzene ring. The m-carbon atom of the benzene ring exhibits the greatest deviation of 0.164 (2) Å from the 19-atom mean plane defined by all non-H atoms. The two N—B—C—C torsion angles are 6.0 (3) and 5.6 (3)°. In the crystal, molecules are linked by π–π interactions into columns, with a distance of 3.92 (3) Å between the naphthalene ring centroids. Adjacent π-stacked columns, co-linear with the b-axis, are linked by C—H⋯π interactions.

The structure shows the molecules to be packed into infinite one-dimensional columns, supported by π···π interactions.

Experimental
To a solution of 1,8-diaminonaphthalene in toluene (4.11 mmol in 50 ml, 0.82M) (Letsinger, 1958, Slabber, 2011 was added the phenylboronic acid (4.11 mmol) in one portion. The round-bottomed flask was equipped with a Dean and Stark trap, and the solution was stirred and heated at 110°C for 3 h. The solvent was removed in vacuo and column chromatography of the crude solid on silica eluting with CH2Cl2 yielded pale green crystalline material in a yield of 77%. Crystals suitable for X-ray diffraction analysis were grown from CH 2 Cl 2 at room temperature.

Refinement
In the absence of significant anomalous scattering, Friedel pairs were merged.
The absolute configuration was arbitrarily assigned.
The relatively large ratio of minimum to maximum corrections applied in the multiscan process (1:nnn) reflect changes in the illuminated volume of the crystal.
Changes in illuminated volume were kept to a minimum, and were taken into account (Görbitz, 1999) by the multi-scan inter-frame scaling (DENZO/SCALEPACK, Otwinowski & Minor, 1997).
The H atoms were all located in a difference map, but those attached to carbon atoms were repositioned geometrically.