Search

A coumarin based Schiff base was found to be an excellent indicator of moisture, via rapid in situ hydrolysis. A structure-relationship examination of a small library of Schiff bases revealed the critical importance of hydrogen bond acceptors in close proximity to the imine bond, and this observation was further supported by theoretical calculations as well as the solid state structure analysis. The most sensitive compound demonstrated a limit of detection and quantification of 0.18% and 0.54% v/v water in DMSO, respectively.

Naphthoimidazolium groups can form unique ionic hydrogen bonds with anions as imidazolium moieties, and in addition, they are fluorescent, so no further elaborative synthesis is needed to introduce a fluorescent group. In this paper, three naphthoimidazolium derivatives were synthesized and studied for the recognition of nucleotides. Compound 1 composed of a single naphthoimidazolium group and quaternary ammonium group did not show any significant fluorescent changes with various anions and nucleotides, such as ATP, GTP, CTP, TTP, UTP, ADP and AMP. A tripodal compound 3 bearing three naphthoimidazolium groups and three quaternary ammonium groups, respectively, showed large fluorescence enhancements with UTP, CTP and TTP and moderate fluorescence enhancements with ATP and pyrophosphate and a fluorescence quenching effect with GTP. On the other hand, compound 2 bearing two naphthoimidazolium groups and two quaternary ammonium groups displayed a selective fluorescence enhancement with ATP and a selective fluorescence quenching effect with GTP in 100% aqueous solution.

Hydrogelation of a pyridine derivative (1) possessing tetrazole moieties as end groups, without long alkyl chain groups, results in the formation of a Mg(NO3)2coordination polymer gel. The polymer exhibits a strong fluorescence enhancement upon gel formation. 1can also be gelated with a variety of magnesium anions such as SO42−, NO3−, Cl−, Br−and I−, indicating that the coordination polymer gel formation of 1does not strongly depend on anions. The SEM and AFM images of Mg2+coordination polymer gel 1display a fibrillar network several micrometres long, with widths in the range of 60–70 nm and thicknesses of about 3 nm. In addition, photophysical studies show that the hydrogel exhibits a typical π–π* transition and gives rise to high fluorescence behavior. The coordination polymer hydrogel exhibits viscoelastic behavior as evidenced from the rheological studies. [ABSTRACT FROM AUTHOR]

A new tetranaphthoimidazolium receptor was synthesized and reported to be a selective fluorescent chemosensor for phytate, myo-inositol hexakisphosphate (IP6). In a 100% aqueous solution at pH 7.4, chemosensor 1 showed a selective fluorescence enhancement for IP6 over IP3, phosphates, pyrophosphates, AMP, ADP and ATP. An excimer emission at 465 nm linearly increases in the range of 300 nM to 1 μM with a detection limit of 2.28 × 10−7 M. In addition, first live cell imaging of IP6 has been demonstrated by using a synthetic receptor. [ABSTRACT FROM AUTHOR]

A rationally designed, coumarin-based fluorescent sensor imino-coumarin (IC) displays high selectivity for Cu2+over a variety of competing metal ions in aqueous solution with a significant fluorescence increase. DFT/TDDFT calculations support that the fluorescence ‘turn-on’ of ICoriginates from blocking the electron transfer of the nitrogen lone pair upon complexation with Cu2+. ICwas successfully applied to microscopic imaging for detection of Cu2+in LLC-MK2 cells (in vitro) and several living organs (in vivo). [ABSTRACT FROM AUTHOR]

An indole conjugated coumarin 1for KCN chemodosimeter has been prepared and displayed considerable dual changes in both absorption (blue-shift) and emission (turn-on) bands exclusively for KCN. DFT/TDDFT calculations support that the fluorescence enhancement of 1-KCN is mainly due to blocking of the ICT process. [ABSTRACT FROM AUTHOR]

A unique colorimetric change of 1, a pyrene based sensor, from light yellow to pink takes place only in the presence of lysine not other tested naturally occurring α-amino acids. [ABSTRACT FROM AUTHOR]

A new bis(pyridine-2-ylmethyl)amine derivative ( 1 ) was synthesized as a colorimetric and fluorescent chemosensor for metal ions. Experimental results indicate that 1 displays significant colorimetric and fluorescent changes upon binding of Cu 2+ . Since 1 has a high water solubility as well as good cell-permeability, it successfully applied to detect the presence of Cu 2+ ion in HepG2 cells in culture medium. Thus, 1 can be used as a potential Cu 2+ chemosensor in aqueous solution and mammalian cells. Further, the fluorescence behavior of 1 upon Cu 2+ binding was well explained by our quantum calculation based on electronic structure. [ABSTRACT FROM AUTHOR]

Abstract: A series of new blue-emitting materials: 2-(10-(naphthalen-2-yl)anthracen-9-yl)pyridine (1); 1-(10-(naphthalen-2-yl)anthracen-9-yl)isoquinoline (2); 9-(3-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-9H-carbazole (3); 9-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-9H-carbazole (4); 9-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)-9H-carbazole (5); 9-(4′-(10-(naphthalen-2-yl)anthracen-9-yl)biphenyl-4-yl)-9H-carbazole (6); and 9-(4′-(10-(naphthalen-1-yl)anthracen-9-yl)biphenyl-4-yl)-9H-carbazole (7) were designed and synthesized via the Suzuki cross-coupling reaction. To explore the electroluminescent properties of these materials, multilayer OLEDs were fabricated in the following sequence: ITO/4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) (50nm)/blue-emitting materials (1–7) (30nm) /4,7-diphenyl-1,10-phenanthroline (Bphen) (30nm)/lithium quinolate (Liq) (2nm)/Al (100nm). Among those, a device using 6 as an emitter exhibited a high external quantum efficiency of 3.83% (3.20% at 20mA/cm2) with CIE coordinates of (0.152,0.114). In order to improve EL efficiency, 1–7 were used as blue host materials for blue dopant materials 4′-[2-(2-diphenylamino-9,9-diethyl-9H-fluoren-7-yl)vinyl]-p-terphenyl (PFVtPh) and 3-(N-phenylcarbazol)vinyl-p-terphenyl (PCVtPh). Using 1 as a host material for blue dopant material PFVtPh, the resultant device showed high EL efficiencies with 10.35cd/A, 8.77lm/W, and 5.70% (10.24cd/A, 6.06lm/W, and 5.66% at 20mA/cm2). Furthermore, using 4 as a host for the PCVtPh blue dopant, device 4c exhibited efficient deep-blue emissions with a maximum external quantum efficiency of 2.96% and CIE coordinates of (0.154,0.087), very close to the NTSC blue standard of (0.14,0.08). [Copyright &y& Elsevier]