Crystal structure and luminescence of 2,7-dimethylnaphthalene-1-carbonitrile

The title compound crystallizes in the monoclinic space group P2(1)/c: M-r = 181.2; a = 7.119(1), b = 18.389(4), c = 7.5385(6) Angstrom; beta = 91.661 (7)degrees; V = 986.4(5) Angstrom(3); and Z = 4. The purified material show s fluorescence similar to other naphthalene derivatives: monomer fluorescen ce (lambda(max) 350-370 nm) in the solid state and in dilute solutions, and excimer fluorescence (lambda(max) 421 nm) in concentrated solutions. Inten se blue-green luminescence (lambda(max) 490 nm) is observed in some partial ly purified crystalline samples. This is attributed to phosphorescence from two isomeric bromodimethylnaphthalenecarbonitrile impurities detected by G C-MS analysis.