Recent Advances in Immobilizing and Benchmarking Molecular Catalysts for Artificial Photosynthesis

Transition metal complexes have been widely used as catalysts or chromophores in artificial photosynthesis. Traditionally, they are employed in homogeneous settings. Despite their functional versatility and structural tunability, broad industrial applications of these catalysts are impeded by the limitations of homogeneous catalysis such as poor catalyst recyclability, solvent constraints (mostly organic solvents), and catalyst durability. Over the past few decades, researchers have developed various methods for molecular catalyst heterogenization to overcome these limitations. In this review, we summarize recent developments in heterogenization strategies, with a focus on describing methods employed in the heterogenization process and their effects on catalytic performances. Alongside the in-depth discussion of heterogenization strategies, this review aims to provide a concise overview of the key metrics associated with heterogenized systems. We hope this review will aid researchers who are new to this research field in gaining a better understanding.

Functional Materials from Biomass-Derived Terpyridines: State of the Art and Few Possible Perspectives

This review focuses on functional materials that contain terpyridine (terpy) units, which can be synthesized from biomass-derived platform chemicals. The latter are obtained by the chemical conversion of raw biopolymers such as cellulose (e.g., 2-furaldehyde) or lignin (e.g., syringaldehyde). These biomass-derived platform chemicals serve as starting reagents for the preparation of many different terpyridine derivatives using various synthetic strategies (e.g., Kröhnke reaction, cross-coupling reactions). Chemical transformations of these terpyridines provide a broad range of different ligands with various functionalities to be used for the modification or construction of various materials. Either inorganic materials (such as oxides) or organic ones (such as polymers) can be combined with terpyridines to provide functional materials. Different strategies are presented for grafting terpy to materials, such as covalent grafting through a carboxylic acid or silanization. Furthermore, terpy can be used directly for the elaboration of functional materials via complexation with metals. The so-obtained functional materials find various applications, such as photovoltaic devices, heterogeneous catalysts, metal-organic frameworks (MOF), and metallopolymers. Finally, some possible developments are presented.

Unveiling the potential of graphene and S-doped graphene nanostructures for toxic gas sensing and solar sensitizer cell devices: insights from DFT calculations

CONTEXT

In this work, we explore the potential of 2D materials, particularly graphene and its derivatives, for eco-friendly electricity generation and air pollution reduction. Leveraging the significant surface area of graphene nanomaterials, the susceptibility of these graphene-based nanostructures to hazardous substances and their applicability in clean solar cell (SSC) devices were systematically investigated using density functional theory (DFT), as implemented within Gaussian 5.0 code. Time-dependent DFT (TD-DFT) was employed to characterize the UV-visible spectrum of unstrained nanostructures. Herein, we considered three potentially harmful gases-CO, NH3, and Br2. Adsorption calculations revealed a notable interaction between the pure graphene nanostructure and Br2 gas, while the S-doped counterpart exhibited reduced interaction. Saturated S-doped nanostructures demonstrated an enhanced affinity for NH3 and CO gases compared to their pure S-doped counterparts, attributed to the sulfur (S) atom facilitating gas molecule binding to the nanostructure's surface. Furthermore, simulations of the SSC device architecture indicated the superior performance of the pure graphene nanostructure in terms of light-harvesting efficiency, injection energy, and electron injection into the lower conduction band of CBM titanium dioxide (TiO2). These findings suggest a potential avenue for developing nanostructures tailored for SSC devices and gas sensors, offering a dual solution to address air pollution concerns.

METHODS

Density function theory was used to compute the ground and excited state properties for pure and sulfur-doped graphene nanostructures. The hybrid function B3LYP with a 6-31G* basis set was utilized to describe the exchange correlation. Gauss Sum 2.2 software is used to estimate the density of state (DOS) for all structures under investigation.

A New Unnatural Amino Acid Derived from the Modification of 4′-(p-tolyl)-2,2′:6′,2″-terpyridine and Its Mixed-Ligand Complexes with Ruthenium: Synthesis, Characterization, and Photophysical Properties

The modification of the methyl group of 4′-(p-tolyl)-2,2′:6′,2″-terpyridine produced the novel unnatural amino acid 3-(4-([2,2′:6′,2″-terpyridin]-4′-yl)phenyl)-2-aminopropanoic acid (phet). Mononuclear heteroleptic ruthenium complexes of the general formulae [Ru(L1)(L2)](PF6)2 (L1 = 2-acetylamino-2-(4-[2,2′:6′,2″]terpyridine-4′-yl-benzyl)-malonic acid diethyl ester, (phem), 3-(4-([2,2′:6′,2″-terpyridin]-4′-yl)phenyl)-2-aminopropanoic acid, (phet), and L2 = 2,2′:6′,2″-terpyridine (tpy), 4′-phenyl-2,2′:6′,2″-terpyridine (ptpy), 4′-(p-tolyl)-2,2′:6′,2″-terpyridine (mptpy)), as well as the homoleptic [Ru(phem)2](PF6)2 and [Ru(phet)2](PF6)2, were synthesized and characterized by means of NMR spectroscopic techniques, elemental analysis, and high-resolution mass spectrometry. The photophysical properties of the synthesized complexes were also studied.