Routes to synthesis of porphyrins covalently bound to poly(carbazole)s and poly(fluorene)s: Structural and computational studies on oligomers

Fluorene-Based Donor-Acceptor Copolymers Containing Functionalized Benzotriazole Units: Tunable Emission and their Electrical Properties

Monomers 4,7-dibromo-2H-benzo[d]1,2,3-triazole (m1) and 4,7-(bis(4-bromophenyl)ethynyl)-2H-benzo[d]1,2,3-triazole (m2) have been synthesized in good yields using different procedures. Monomers m1 and m2 have been employed for building new copolymers of fluorene derivatives by a Suzuki reaction under microwave irradiation using the same conditions. In each case different chain lengths have been achieved, while m1 gives rise to polymers for m2 oligomers have been obtained (with a number of monomer units lower than 7). Special interest has been paid to their photophysical properties due to excited state properties of these D-A units alternates, which have been investigated by density functional theory (DFT) calculations using two methods: (i) An oligomer approach and (ii) by periodic boundary conditions (PBC). It is highly remarkable the tunability of the photophysical properties as a function of the different monomer functionalization derived from 2H-benzo[d]1,2,3-triazole units. In fact, a strong modulation of the absorption and emission properties have been found by functionalizing the nitrogen N-2 of the benzotriazole units or by elongation of the π-conjugated core with the introduction of alkynylphenyl groups. Furthermore, the charge transport properties of these newly synthesized macromolecules have been approached by their implementation in organic field-effect transistors (OFETs) in order to assess their potential as active materials in organic optoelectronics.

Synthetic aspects of carbazole containing porphyrins and porphyrinoids

Porphyrins are tetrapyrrolic aromatic macrocycles and ubiquitous in nature. They are excellent dyes with strong absorption in the visible region (400–700 nm) and they exhibit decent fluorescence in the red region (620–900 nm). Carbazole is a nitrogen-containing electron rich aromatic heterocycle which can be linked to porphyrins and other chromophores. This review provides an overview of the different synthetic strategies that have been employed to prepare carbazole-substituted porphyrins and carbazole-fused porphyrinoids and similar systems. It also shows that how the substitution of carbazole occurs on the porphyrin core can alter its optical and electronic features. Introduction of carbazole moieties in the porphyrin ring resulted in fused porphyrinoids with changed aromaticity and significantly altered electronic features of the molecules.

Theoretical and experimental analysis of porphyrin derivatives with suitable anchoring groups for DSSC applications

In this contribution, different porphyrin derivatives were experimentally synthesized and theoretically analyzed using several electronic structure methods to study the geometrical and electronic properties of A4, trans-A2B[Formula: see text]and A3B porphyrins bearing several functional groups (–OH, –COOH, -3,5-di-[Formula: see text]Bu, –OCH2CH2CH2COOEt and –OMe) suitable to be employed as dyes in Dye Sensitized Solar Cells (DSSC). A4 (R [Formula: see text] -H, -OMe, -OH, -3,5-di-tert-butyl, –OCH2CH2CH2COOEt) and A3B (R[Formula: see text][Formula: see text]R[Formula: see text][Formula: see text]R[Formula: see text][Formula: see text]–H; R[Formula: see text][Formula: see text]–OH and R[Formula: see text][Formula: see text]-3,5-di-[Formula: see text]Bu) porphyrins were synthesized and characterized by UV-vis and 1H NMR spectroscopies for comparison. The geometrical parameters were analyzed in the ground state and gas phase using the semiempirical method PM6 and the DFT functionals M06-2X and B3LYP, in combination with the 6-31G(d), DZVP and TZVP basis set. For calculations of the electronic and excited state properties, CAM-B3LYP, M06-2X and HSE06, using SMD as solvation model, were applied. This study revealed that HSE06/DZVP protocol is the best methodology to simulate electronic spectra in these porphyrin derivatives. Indeed, whereas substituent groups did not significantly affect the geometrical structure of the porphyrin derivatives studied, they do influence their electronic structures, mainly in the LUMO (lowest unoccupied molecular orbital) energy levels.

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation

The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the function of optical power limiting. All known mechanisms of optical limiting have been analyzed and discussed for the different types of materials.

Cost-efficient method for unsymmetrical meso-aryl porphyrins and iron oxide-porphyrin hybrids prepared thereof

Synthesis, characterisation and photophysical properties of magnetic iron oxide-porphyrin hybrids starting from unsymmetrical porphyrins, which are prepared by a cost-efficient methodology.

Ecofriendly porphyrin synthesis by using water under microwave irradiation

Water, under microwave irradiation and at a temperature of 473 K, reaches pressures above 16 bar, being capable to act as catalyst, without the use of organic solvents and oxidants, for meso-substituted porphyrin synthesis. Sustainability of the reaction is proved by E Factor=35 and EcoScale value of 50.5, the highest so far obtained for porphyrin synthesis. Methodology's wide versatility is clearly demonstrated by the good yields obtained for both aryl and alkyl substituted porphyrins. These reaction conditions represent a huge development, not only by using very high concentrations, minimizing organic solvent usage, but also by eradicating toxic expensive solvents and oxidants.