Structure and phosphorescence of meta-bromobenzophenone crystal

Solid state properties of meta-bromobenzophenone crystals were studied, including X-ray diffraction, integrated phosphorescence spectrometry, and ab initio calculations. The structure of meta-bromobenzophenone crystals has been determined by powder X-ray diffraction to be orthorhombic (space group Pbca) with a = 11.70461(15) Å, b = 7.70025(9) Å, c = 24.0055(2) Å, Z = 8. This structure includes a supramolecular network formed by weak hydrogen bonds of CH ⋯ O and CH ⋯ π short contacts. A tight π–π short contact between virtually parallel substituted and unsubstituted phenyl rings of neighbor molecules is another distinguishing feature of the crystal structure, which might be the cause of the unusual very broad lonely band in the room-temperature phosphorescence spectrum. The low-temperature (1.6 K) phosphorescence spectra are of monomeric character, revealing sharp lines superimposed on broad 0 → ν bands, which is a signature of emission from some traps.

► Crystal structure of meta-bromobenzophenone (3BrBP) determined at room temperature.
► Analysis of weak bonding in 3BrBP.
► Integral phosphorescence spectra measured at room and liquid-helium temperatures.