Unconventional Fluorescence Quenching in Naphthalimide-Capped CdSe/ZnS Nanoparticles
Core–shell (CS) CdSe/ZnS quantum dots (QD) capped with ligands that possess a mercapto or an amino group and a naphthalimide (NI) as chromophore unit, linked by a short ethylene chain (CS@S–NI and CS@H2N–NI, respectively), have been synthesized and fully characterized by infrared and nuclear magnetic resonance spectroscopies, high-resolution transmission electron microscopy, and voltammetry as well as by steady-state absorption and emission spectroscopies. The organic ligands HS–NI and H2N–NI act as bidentate ligands, thereby causing a drastic decrease in the QD emission. This was particularly evident in the case of CS@S–NI. This behavior has been compared with that of commercially availabl…
Electronic and Functional Scope of Boronic Acid Derived Salicylidenehydrazone (BASHY) Complexes as Fluorescent Dyes
[EN] A series of boronic acid derived salicylidenehydrazone (BASHY) complexes was prepared and photophysically characterized. The dye platform can be modified by (a) electronic tuning along the cyanine-type axis via modification of the donor-acceptor pair and (b) functional tuning via the boronic acid residue. On the one hand, approach (a) allows the control of photophysical parameters such as Stokes shift, emission color, and two-photon absorption (2PA) cross section. The resulting dyes show emission light-up behavior in nonpolar media and are characterized by high fluorescence quantum yields (ca. 0.5-0.7) and brightness (ca. 35000-40000 M-1 cm(-1)). Moreover, the 2PA cross sections reach …