Solvent effects on the electronic and optical properties of Ni(II), Zn(II), and Fe(II) complexes of a Schiff base derived from 5-bromo-2-hydroxybenzaldehyde

In this article, the electronic, optical, and charge transfer properties of a Schiff base ligand prepared using 5-bromo-2-hydroxybenzaldehyde and ethyl 6-acetyl-2-amino-4,5,6,7-tetrahydrothieno[2,3- c]pyridine-3-carboxylate (C19H19BrN2O4S) and its Fe(II) (C19H30BrN2O10SClFe), Ni(II) (C19H28BrN2O9SClNi), and Zn(II) (C19H28BrN2O9SClZn) complexes are described based on different solvents environments and supported by theoretical calculations. Theoretical calculations are carried out using density functional theory (DFT/UB3LYP/LANL2DZ). The optical densities, optical band gaps, and refractive indices of the ligand and its Fe(II), Ni(II), and Zn(II) complexes in different solvent environments are obtained. The reorganization energies are calculated to determine the charge transfer rate of the studied compounds using both experimental and theoretical data. These experimental and theoretical results show that the ligand and its metal complexes can be used for optoelectronic applications and charge transfer materials in organic light-emitting diode applications.

Pure and mixed ordered monolayers of tetracyano-2,6-naphthoquinodimethane and hexathiapentacene on the Ag(100) surface

We report on mixed ordered monolayers of the electron acceptor-type molecule tetracyano-2,6-naphthoquinodimethane (TNAP) and the electron donor-type molecule hexathiapentacene (HTPEN). This investigation was motivated by the general question which type of mixed stoichiometric structures are formed on a surface by molecules that are otherwise typically used for the synthesis of bulk charge-transfer materials. The layers were obtained by vacuum deposition on the Ag(100) surface and analyzed by low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). The formation of the mixed structure occurs spontaneously. An important motif for the structure formation is given by hydrogen bonds between the TNAP molecules. Both molecules, TNAP and HTPEN also form well-ordered monolayers on the Ag(100) surface on their own. In all structures, the molecules are adsorbed in a planar orientation on the surface. We discuss the influence of intermolecular charge transfer on the ordering in the mixed structure.

Towards the rational design of novel charge-transfer materials: biaryls with a dihedral angle-independent hole delocalization mechanism

Herein, we demonstrate a rational design of novel materials using FMO analysis on the example of biaryls with dihedral angle independent mechanism of hole delocalization.

Organic Functionalization and Properties of ZnO Nanosheets with Polymer Containing N-Vinyl Carbazole

To make full use of the visible light more effectively, many studies are focuses on ZnO baesd nanocomposites. To modify the surface of ZnO with functional polymer is a very simple and effective approach. PVK (N-vinyl carbazole polymer) is one of typical organic functional materials, which is generally used as charge transfer materials for the applications of several organic electronic devices. Surface modification of ZnO nanosheets with polymer containing –COOH and N-vinyl carbazole group was performed with self-assembly process for improving the adsorption to visible light and properties of charge transfer in nanoscale. A series of characterizations were carried out by SEM (scanning electron microscopy), Fourier-Transform Infrared (FTIR) spectra, UV-Vis (Ultra-violet visible spectroscopy), et al. The adsorption of the nanocomposite was extended to the region of visible light. The photoconductivity response to weak visible light was studied based on interdigital electrodes of Au on flexible PET (polyethylene terephthalate) film substrate with casting method. The photocurrent of ZnO nanosheets modified with the polymer containing N-vinyl carbazole to weak visible light was changed greatly. The organic-inorganic nanocomposite showed good activities to visible light, with which it can be easily produced photo-induced charges, avoiding the recombination of charges produced by visible light. Photocatalytic efficiency was examined by selecting typical organic pollutants and some good results were obtained, showing much prospect in the fields of photocatalysts, nanoreactors, self-cleaning films, coatings, and organic pollutants treatment of environmental.