Two Different Emissions of (2Z)-2-(4-Bromopheny1)-3-[4-(dimethylannino)phenyllprop-2-enenitrile Due to Crystal Habit and Size: Synthesis, Optical, and Supramolecular Characterization

Optical and X-ray diffraction characterizations of crystals I and II of (2Z)-244-bromopheny1)-3-[4-(dimethylamino)phenyl]prop2-enenitrile (Z-4-BrPhDMAPhACN) are reported. I and II belong to the same monoclinic space group and have nearly identical unit-cell dimensions [I: a = 11.0169(2); b = 6.02041(11); c = 21.8541(4); (6) 98.4082(18). II: a 7)1.0475(6); b = 6.0273(3); c = 21.8533(11); (beta) 98.315(5)]. Crystals I and II were formed under different conditions and have different crystal habits and colors: crystals I are yellow blocks, whereas crystals II are small, orange needles. I and II show absorption maxima (tabs) in solution at 404 rum and emission (2) maxima at 501 nm (I) and at 502 Inn (II). However, their emission maxima are different in the solid state: I shows an emission at 512 nm and a shoulder at 534 nm, whereas II exhibits a lambda(em) maximum at 582 nm. The differences in solid-state photoluminescence were attributed to variations in the crystal morphology and to the crystal habit and size. Both I and II were characterized.by nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, UV-vis spectroscopy, fluorescence, cyclic voltammetry, single-crystal and powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and density functional theory calculations.