Engineering MOF/carbon nitride heterojunctions for effective dual photocatalytic CO conversion and oxygen evolution reactions.

Photocatalysis appears as one of the most promising avenues to shift towards sustainable sources of energy, owing to its ability to transform solar light into chemical energy, production of chemical fuels oxygen evolution (OER) and CO reduction (CORR) reactions. Ti metal-organic frameworks (MOFs) and graphitic carbon nitride derivatives, poly-heptazine imides (PHI) are appealing CORR and OER photo-catalysts respectively. Engineering of an innovative Z-scheme heterojunction by assembling a Ti-MOF and PHI offers an unparalleled opportunity to mimick an artificial photosynthesis device for dual CORR/OER catalysis.

Exploring structural and optical properties of iodine-doped TiO nanoparticles in Rhodamine-B dye degradation: Experimental and theoretical investigation.

Energy conversion and pollutant degradation are critical for advancing sustainable technologies, yet they often encounter challenges related to charge recombination and efficiency limitations. This study explores iodine-doped TiO nanoparticles as a potential solution for enhancing both energy conversion and pollutant degradation. The nanoparticles were synthesized via the sol-gel method with varying iodine precursor concentrations (0.

Electronic, optical and charge transport properties of Zn-porphyrin-C MOFs: a combined periodic and cluster modeling.

Density functional theory (DFT) calculations were performed on the 5,15 meso-positions of nine porphyrin-containing MOFs; Zn(TCPB)-(NMe-ZnP); (HTCPB = 1,2,4,5-tetrakis(4-carboxyphenyl)benzene), (NMe-ZnP = [5,15-bis[(4-pyridyl)-ethynyl]-10,20-bis-(dimethylamine) porphinato]zinc(II)) functionalized with nitrogen-, oxygen-, and sulfur-containing groups to study their effects on the electronic, optical and transport properties of the materials. The properties of these materials have also been investigated by encapsulating fullerene (C) in their pores (C@MOFs). The results indicate that the guest C in the MOF generates high photoconductivity through efficient porphyrin/fullerene donor-acceptor (D-A) interactions, which are facilitated by oxygen and sulfur functionalities.

Correction: Computational demonstration of isomer- and spin-state-dependent charge transport in molecular junctions composed of charge-neutral iron(II) spin-crossover complexes.

Correction for 'Computational demonstration of isomer- and spin-state-dependent charge transport in molecular junctions composed of charge-neutral iron(II) spin-crossover complexes' by Nicolás Montenegro-Pohlhammer, , , 2023, , 1229-1240, https://doi.org/10.1039/D2DT02598A.

Toward the search for new photosensitizers for DSSCs: theoretical study of both substituted Zn(II) and Si(IV) phthalocyanines.

We report a density functional theory (DFT) study performed for a set of 66 compounds based on zinc(II) and silicon(IV) phthalocyanines (Pcs) with potential applications in dye-sensitized solar cells (DSSCs). The effect of the metal center (Zn, Si), periplanar and axial substituents, and anchor groups like anhydrous, carboxyl, and catechol on the electronic, optical, photovoltaics, and adsorption properties is investigated. Using the TD-DFT methodology and M06 and CAM-B3LYP functionals, we calculated the absorption spectra on optimized structures and in the solution phase but not on structures relaxed in the solvent.

Deciphering the origin of the first steps in the degradation of azo dyes: a computational study.

Azo dyes find applications across various sectors including food, pharmaceuticals, cosmetics, printing, and textiles. The contaminating effects of dyes on aquatic environments arise from toxic effects caused by their long-term presence in the environment, buildup in sediments, particularly in aquatic species, degradation of pollutants into mutagenic or mutagenic compounds, and low aerobic biodegradability. Therefore, we theoretically propose the first steps of the degradation of azo dyes based on the interaction of hydroperoxyl radical (•OOH) with the dye.

Computational demonstration of isomer- and spin-state-dependent charge transport in molecular junctions composed of charge-neutral iron(II) spin-crossover complexes.

Chemistry offers a multitude of opportunities towards harnessing functional molecular materials with application propensity. One emerging area of interest is molecular spintronics, in which charge and spin degrees of freedom have been used to achieve power-efficient device architectures. Herein, we show that, with the aid of state-of-the-art quantum chemical calculations on designer molecular junctions, the conductance and spin filtering capabilities are molecular structure-dependent.

Anisotropic Band-Edge Absorption of Millimeter-Sized Zn(3-ptz) Single-Crystal Metal-Organic Frameworks.

Metal-organic frameworks (MOFs) have emerged as promising tailor-designed materials for developing next-generation solid-state devices with applications in linear and nonlinear coherent optics. However, the implementation of functional devices is challenged by the notoriously difficult process of growing large MOF single crystals of high optical quality. By controlling the solvothermal synthesis conditions, we succeeded in producing large individual single crystals of the noncentrosymmetric MOF Zn(3-ptz) (MIRO-101) with a deformed octahedron habit and surface areas of up to 37 mm.

Fullerene binding effects in Al(III)/Zn(II) Porphyrin/Phthalocyanine photophysical properties and charge transport.

We evaluate the fullerene C binding effect; through the metal (Al) and through the ligand (Pc,TPP), on the photophysical and charge transport properties of M-porphyrin(TPP)/phthalocyanine(Pc) (M = Al(III), Zn(II)). We perform density functional theory (DFT) and time-dependent DFT calculations for the macrocycle-C dyads, showing that all systems studied are thermodynamically favorable. The C binding effect on the absorption spectrum is a red-shift of the Q and Soret (B) bands of TPPs and Pcs.

A photo-induced spin crossover based molecular switch and spin filter operating at room temperature.

Since Venkataramani et al. (Science, 2011, 331(6016), 445-448) reported reversible, room-temperature light-induced spin crossover in Ni-porphyrin functionalized with a phenylazopyridine ligand (NiTPP-PAPy), this complex has attracted the attention of many researchers due to its potential applications in molecular-based devices. In this work, we perform a detailed study, by means of DFT and WFT methodologies, focused on the deposition of NiTP-PAPy over an Au(111) surface, followed by DFT-NEGF calculations employing a gold surface and the tip of an STM as electrodes, in order to probe the deposited complex's transport properties.

Assessment of New Expanded Porpholactones as UV/Vis/NIR Chromophores for Dye-Sensitized Solar Cell Applications.

Expanded porphyrins arise as an alternative for potential application as chromophores in dye-sensitized solar cells. (DSSCs). The modification of the core of these compounds provides remarkable changes in the photoelectronic behavior.

Local and macrocyclic (anti)aromaticity of porphyrinoids revealed by the topology of the induced magnetic field.

The aromaticity in porphyrinoids results from the π conjugation through two different annular perimeters: the macrocyclic ring and the local heterocyclic rings appended to it. Analyses, based on aromatic stabilization energies (ASE), indicate that the local circuits (6π) are responsible for the significant aromatic stabilization of these systems. This local aromaticity can be coupled with the one from 4n + 2π macrocyclic circuit.

Orbital-Weighted Dual Descriptor for the Study of Local Reactivity of Systems with (Quasi-) Degenerate States.

An alternative response function, based on the dual descriptor in terms of Koopmans' approximation, is hereby proposed for the description of chemical reactivity in systems with (quasi-) degenerate frontier molecular orbitals. This descriptor is constructed from Fukui functions that include contributions from different orbitals, i.e.

Spin-filter transport and magnetic properties in a binuclear Cu(ii) expanded porphyrin based molecular junction.

Although the magnetic and transport properties of molecular junction systems composed of metalled porphyrins or phthalocyanines have been broadly studied in recent years, to date no studies have been devoted to evaluate the aforementioned properties in junction systems featuring metalled expanded porphyrins as active elements. The present work reports a detailed theoretical study of the magnetic and electronic transport properties of the recently synthesized dinuclear Cu(ii)-naphthoisoamethyrin complex (PyCu). This is the first work on performing these kinds of studies using a magnetically coupled metallic expanded porphyrin as a molecular kernel.

The influence of antenna and anchoring moieties on the improvement of photoelectronic properties in Zn(ii)-porphyrin-TiO as potential dye-sensitized solar cells.

A systematic study for the rational design of porphyrins (P4 spider-shaped derivatives) with potential application in dye-sensitized solar cells is presented. Using density functional theory (DFT) (B3LYP/6-31G*) and time-dependent DFT (M06/6-31G*) we show that the UV-vis absorption properties of a spider-shaped Zn(ii) porphyrin, previously synthesized by Stangel et al., may be greatly improved by applying some push-pull strategies in meso positions.

Theoretical rationalisation of the photophysics of a TICT excited state of cinnamoyl-coumarin derivatives in homogeneous and biological membrane models.

A new hybrid cinnamoyl-coumarin probe was synthesised to study the formation and dynamics of a twisted internal charge transfer (TICT) excited state in homogeneous and biological membrane models. This probe showed a large bathochromic shift of the fluorescence band with the solvent polarity, which is associated with the decrease in the fluorescence intensity due to fast non-radiative deactivation pathways, ascribed to TICT excited state formation in polar solvents. The calculated potential energy surfaces using density functional theory (DFT) and time dependent-DFT (TD-DFT) along with the energetic barriers calculated using the ABF methodology established the energy requirements for a rotational twisting of the cinnamoyl-coumarin bond for TICT excited state formation.

Atypical antioxidant activity of non-phenolic amino-coumarins.

Coumarin compounds have been described as anti-inflammatories, and chemotherapeutic agents as well as antioxidants. However, the origin of the antioxidant activity of non phenolic coumarins remains obscure. In the present report, we demonstrate that non-phenolic 7-dialkyl-aminocoumarins may also have significant antioxidant properties against free radicals derived from 2,2'-azobis(2-amidinopropane) dihydrochloride under aerobic conditions.

Reaction Kinetics of Phenolic Antioxidants toward Photoinduced Pyranine Free Radicals in Biological Models.

8-Hydroxy-1,3,6-pyrenetrisulfonic acid (pyranine, PyOH) free radicals were induced by laser excitation at visible wavelengths (470 nm). The photochemical process involves photoelectron ejection from PyO- to produce PyO• and PyO•- with maxima absorption at 450 and 510 nm, respectively. The kinetic rate constants for phenolic antioxidants with PyO•, determined by nanosecond time-resolved spectroscopy, were largely reliant on the ionic strength depending on the antioxidant phenol/phenolate dissociation constant.

Insights on the Reactivity of Terminal Phosphanido Metal Complexes toward Activated Alkynes from Theoretical Computations.

Herein we present a theoretical study on the reaction of [Re(PPh) (CO)(phen)] (phen = 1,10-phenanthroline) and [Re(PPh) (CO)(bipy)] (bipy = 2,2'-bipyridine) toward methyl propiolate. In agreement with experimental results for the phen ligand, the coupling of the substituted acetylenic carbon with the nonsubstituted ortho carbon of the phen ligand is the preferred route from both kinetic and thermodynamic viewpoints with a Gibbs energy barrier of 18.8 kcal/mol and an exoergicity of 11.