TY - JOUR A1 - Nirmalananthan-Budau, Nithiya A1 - Behnke, Thomas A1 - Hoffmann, Katrin A1 - Kage, Daniel A1 - Gers-Panther, Charlotte F. A1 - Frank, Walter A1 - Müller, Thomas J. J. A1 - Resch-Genger, Ute T1 - Crystallization and Aggregation-Induced Emission in a Series of Pyrrolidinylvinylquinoxaline Derivatives N2 - Aggregation-induced emission (AIE) has been meanwhile observed for many dye classes and particularly for fluorophores containing propeller-like groups. Herein, we report on the AIE characteristics of a series of four hydrophobic pyrrolidinylvinylquinoxaline (PVQ) derivatives with phenyl, pyrrolyl, indolyl, and methoxythienyl substituents used to systematically vary the torsion angle between this substituent at the quinoxaline C2 position and the planar PVQ moiety. These molecules, which are accessible via four- or five-component one-pot syntheses, were spectroscopically studied in organic solvents and solvent−water mixtures, as dye aggregates, solids, and entrapped in polystyrene particles (PSP). Steady-state and time-resolved fluorescence measurements revealed a strong fluorescence enhancement for all dyes in ethanol−water mixtures of high water content, accompanying the formation of dye aggregates with sizes of a few hundred nm, overcoming polarity and H-bonding-induced fluorescence quenching of the chargetransfer-type emission of these PVQ dyes. The size and shape of these dye aggregates and the size of the AIE effect are controlled by the water content and the substituent-dependent torsion angle that influences the nucleation process and the packing of the molecules during aggregation. Staining of 1 μm-sized carboxy-functionalized PSP with the PVQ dyes resulted also in a considerable increase in the fluorescence quantum yield and lifetime, reflecting the combined influence of the restricted molecular motion and the reduced polarity of the dye microenvironment. KW - Spectroscopy KW - AIE KW - Aggregates KW - Nanoparticle PY - 2018 U6 - https://doi.org/10.1021/acs.jpcc.8b01425 SN - 1932-7447 N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. VL - 122 IS - 20 SP - 11119 EP - 11127 PB - ACS Publications AN - OPUS4-45176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -