Solvatochromism and pH effect on the emission of a triphenylimidazole-phenylacrylonitrile derivative: experimental and DFT studies.

In this work, a study of the photophysical properties in different solvents and at different pH values of a luminogenic compound with a donor-π-acceptor (D-π-A) structure was carried out. The compound (Z)-3-(4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-2-phenylacrylonitrile (2) was synthesized and characterized by SCXRD, FT-IR, 1H NMR, 13C NMR, EIMS, UV-Vis absorption and fluorescence. The SCXRD characterization reveals a monoclinic system, P21/c, with Z = 4 and an imidazole core having hydrogen bonding with respect to water molecules present in the asymmetric unit. It leads to a strong π-π-interaction in the solid state. The fluorescence λ max emission of the powder and thin film was observed at 563 nm and 540 nm respectively. Several degrees of positive solvatochromic fluorescence were observed due to different molecular conformations in various solvents. When the pH of the compound was changed with HCl or NaOH, a shift in the wavelength of emission was observed in a reversible manner. At pH 2, the λ max of emission was at 541 nm whereas at pH 14 there were two emissions at 561 nm and 671 nm. Due to their good emission in the solid state, compound 2 was tested as an emitting layer in OLEDs; the devices showed an acceptable performance with a luminance average of 450 cd m-2. The band gap was analyzed by optical absorption, cyclic voltammetry measurement and DFT calculations.

A low molecular weight OLED material: 2-(4-((2-hydroxyethyl)(methyl)amino)benzylidene)malononitrile. Synthesis, crystal structure, thin film morphology, spectroscopic characterization and DFT calculations.

2-(4-((2-Hydroxyethyl)(methyl)amino)benzylidene)malononitrile (HEMABM) was synthesized from 4-[hydroxymethyl(methyl)amino]benzaldehyde and propanedinitrile to obtain a low molecular weight fluorescent material with an efficient solid-state emission and electroluminescence properties comparable to the well-known poly(2-methoxy-5(2'-ethyl)hexoxyphenylenevinylene) (MEH-PPV). The HEMABM was used to prepare an organic light-emitting diode by a solution process. Despite the title compound being a small molecule, it showed optical properties and notable capacity to form a film with smooth morphology (10.81 nm) closer to that of polymer MEH-PPV (10.63 nm). The preparation of the device was by spin coating, the electrical properties such as threshold voltage were about 1.0 V for both HEMABM and MEH-PPV, and the luminance 1300 cd m-2 for HEMABM and 2600 cd m-2 for MEH-PPV. This low molecular weight compound was characterized by SCXRD, IR, NMR, and EI. Besides a quantitative analysis of the intermolecular interactions by PIXEL, density functional theory (DFT) calculations are reported.

Orally available stilbene derivatives as potent HDAC inhibitors with antiproliferative activities and antitumor effects in human tumor xenografts.

Herein we report the synthesis and activity of a novel class of HDAC inhibitors based on 2, 3-diphenyl acrylic acid derivatives. The compounds in this series have shown to be potent HDAC inhibitors possessing significant antiproliferative activity. Further compounds in this series were subjected to metabolic stability in human liver microsomes (HLM), mouse liver microsomes (MLM), and exhibits promising stability in both. These efforts culminated with the identification of a developmental candidate (5a), which displayed desirable PK/PD relationships, significant efficacy in the xenograft models and attractive ADME profiles.