Polymorphism and White Light Emission of 1‐Bromo‐3,5,7‐triphenyladamantane Compared with 1,3,5,7‐Tetraphenyladamantane

Here we report our investigation of 1‐bromo‐3,5,7‐triphenyladamantane ( 1 ) and the elucidation of polymorphic crystals ( 1 A and 1 B ) using single crystal X‐ray diffraction. In the monoclinic crystal system of 1 A ( P 2 1 / n ), we observed CH–π interactions, while Br⋅⋅⋅Br interactions are absent. Conversely, the Br⋅⋅⋅Br interactions are an apparent factor in the formation of the monoclinic crystal system of 1 B ( R ). We compare our findings with 1,3,5,7‐tetraphenyladamantane ( 2 ), characterized by numerous CH–π interactions in the solid. Computational analyses were employed to investigate the interactions within the characteristic dimers present in the unit cells of 1 A and 1 B , including visualization of noncovalent interactions and the use of the atoms‐in‐molecules approach as well as MO analyses. These support the notion of London dispersion (LD) dimer‐dimer interactions in 1 A between the phenyl moieties, whereas 1 B exhibits additional dimer‐dimer Br⋅⋅⋅Br contacts. In contrast, the crystals of 2 are exclusively held together by CH–π stacking LD interactions, a feature absent in the polymorphs of 1 . Both polymorphic forms of 1 emit white light when subjected to 900 nm continuous wave laser irradiation, displaying a subtle blue shift compared to 2 . The absence of CH–π stacking interactions between the dimers of 1 causes a small red‐shift in the emission spectrum.