Photonics of boron(III) and zinc(II) dipyrromethenates as active media for modern optical devices

XPS and quantum chemical analysis of 4Me-BODIPY derivatives

The results of a X-ray photoelectron spectroscopy (XPS) and steady-state absorption spectroscopy study of the electronic structure, and cationic and excited states of a series of 1,3,5,7-tetramethyl-substituted BODIPYs (4Me,2R-BODIPYs) are presented. The experimental data were interpreted using high-level ab initio quantum chemical computations, including the algebraic diagrammatic construction method for the polarization propagator of the second order (ADC(2)), the outer-valence Green's function (OVGF) method, the density functional (DFT) approach, and the time-dependent DFT (TD-DFT) approach. Substitution effects on the XPS and absorption spectra were determined for 2,6-positions of 4Me,2R-BODIPY pyrrole nuclei (R = H, Br, Bu, benzyl). A very satisfactory performance of the DFT Koopmans theorem analogue was demonstrated with respect to the energy intervals between the electronic levels of 4Me,2R-BODIPY above 13 eV (BHHLYP functional) and the values of the HOMO-LUMO energy gap (ωB97X functional).

Stability of Dibromo-Dipyrromethene Complexes Coordinated with B, Zn, and Cd in Solutions of Various Acidities

The spectral luminescent properties of dipyrromethenates halogenated with bromine on both ends of the long axis and coordinated using boron fluoride, zinc, or cadmium in neutral ethanol and acidified with hydrochloric acid solutions were studied. The constants of the acid-base equilibrium of the complexes in the proton-donor solvents in the ground and excited states was determined. The mechanisms of complex protonation were discussed, depending on the structure of the compounds. The electronic structures of the neutral and protonated compounds were modeled and analyzed based on the quantum-chemical method. The structures and spectral-luminescence properties were calculated using the SMD model of ethanol solvent using the TD-DFT theory with the B3LYP functional and the composite def2-SVP/def2-TZVP/def2-TZVPP_ECP basis sets, depending on the atomic number of the elements.

Can machine learning methods accurately predict the molar absorption coefficient of different classes of dyes?

In this article, we provide a convenient tool for all researchers to predict the value of the molar absorption coefficient for a wide number of dyes without any computer costs. The new model is based on RFR method (ALogPS, OEstate + Fragmentor + QNPR) and is able to predict the molar absorption coefficient with an accuracy (5-fold cross-validation RMSE) of 0.26 log unit. This accuracy was achieved due to the fact that the model was trained on data for more than 20,000 unique dye molecules. To our knowledge, this is the first model for predicting the molar absorption coefficient trained on such a large and diverse set of dyes. The model is available at https://ochem.eu/article/145413. We hope that the new model will allow researchers to predict dyes with practically significant spectral characteristics and verify existing experimental data.

Synthesis and characterization of a mononuclear zinc(ii) Schiff base complex: on the importance of C-H⋯π interactions

A zinc(ii) complex, [ZnL(H₂O)]·H₂O {H₂L = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(nitrilomethylidyne)]bis[6-ethoxyphenol]} has been synthesized and characterized by UV-vis and IR spectroscopy. The structure of the complex has been confirmed by X-ray crystallography and the noncovalent interactions characterized using Hirshfeld surface analysis. In addition to the conventional H-bonds involving the Zn-coordinated and non-coordinated water molecules, interesting C–H⋯π interactions between the H-atoms belonging to aliphatic part of the ligand (2,2-dimethyl-1,3-propanediyl) and the Zn-coordinated aromatic rings are established. These interactions have been studied using DFT calculations (PBE0-D3/def2-TZVP) and characterized using molecular electrostatic potential (MEP) surfaces and the noncovalent interaction (NCI) plot index analyses.

The strength of the C–H⋯π interaction in the solid state of [ZnL(H₂O)]·H₂O has been evaluated using DFT calculations and also analysed using the MEP surface and NCI plot index computational tool.

BODIPY-Based Molecules, a Platform for Photonic and Solar Cells

The 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based molecules have emerged as interesting material for optoelectronic applications. The facile structural modification of BODIPY core provides an opportunity to fine-tune its photophysical and optoelectronic properties thanks to the presence of eight reactive sites which allows for the developing of a large number of functionalized derivatives for various applications. This review will focus on BODIPY application as solid-state active material in solar cells and in photonic devices. It has been divided into two sections dedicated to the two different applications. This review provides a concise and precise description of the experimental results, their interpretation as well as the conclusions that can be drawn. The main current research outcomes are summarized to guide the readers towards the full exploitation of the use of this material in optoelectronic applications.