Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer.

A series of novel soluble nature-inspired flavin derivatives substituted with short butyl and bulky ethyl-adamantyl alkyl groups was prepared via simple and straightforward synthetic approach with moderate to good yields. The comprehensive characterization of the materials, to assess their application potential, has demonstrated that the modification of the conjugated flavin core enables delicate tuning of the absorption and emission properties, optical bandgap, frontier molecular orbital energies, melting points, and thermal stability. Moreover, the thin films prepared thereof exhibit smooth and homogeneous morphology with generally high stability over time.

Natural or nature-inspired molecules play a key role in many modern applications as they may imitate nature in the efficiency with which it works in a different spectrum of biological processes. One of the biggest challenges today is to make efficient use of renewable energy sources, that are lagging behind conventional technologies on a global scale. One form of this renewable energy is solar energy which can be garnered by organic photovoltaics (OPV). The golden wave of OPV can be observed with the advent of non-fullerene acceptors (NFAs). Chemical derivatizations, low band gap, broad absorption and sufficient stability, predetermine them for the successful construction of functional devices. The review summarizes some important aspects of the use of natural and nature-inspired materials, their design, and use for NFAs, and light power conversion efficiency. We also discuss some photocatalytic applications as a contribution to green renewable energy and solar-fuels production.

No abstract

No abstract

No abstract

The synthesis, experimental and theoretical study of the novel air-stable four adamantane-bearing dyes based on the transepindolidione (EPI) and trans-quinacridone (QA) cores are presented. Compared to the parent EPI and QA, the methyl-/ ethyladamantyl substitution ensures that their structural stability in crystals is preserved due to the self-organizing properties of adamantyl groups. The investigated materials are solutionprocessable in common organic solvents and possess excellent thermal stability. The very good solubility was achieved by a one-step short and easy synthesis, which resulted in moderate yields of a new family of synthesized dyes. The ethyladamantyl EPI derivative (3) exhibits a unique rise in thermal stability reaching 412 °C. The resulting electrochemical band gap carried out on thin-film evaporated on ITO-coated glass electrodes was in the range of 2.4-2.5 eV. The experimental HOMO energies range from À 6.2 to À 6.0 eV, and LUMO energies lay between À 3.7 and À 3.5 eV. The prepared compounds are characterized by strong fluorescence in solutions and in powder, suggesting a decrease in the extent of non-radiative relaxation processes.

A systematic study of (7,8-dimethylated) alloxazine, isoalloxazine, and their derivatives with substituted N(1) and N(10) positions was conducted using the density functional theory. The main aim of this work was the direct investigation of substituent effect on the molecular structure. Furthermore, HOMED aromaticity indices were calculated to describe the scope of the geometry changes. Frontier molecular orbitals of reference alloxazine, isoalloxazine and lumichrome derivatives were discussed by means of changes in their shape and energy levels. Photophysical properties were analyzed by determination of optical transition energies using the TD-DFT method. Obtained results were compared with previously published experimental data.