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A novel mononuclear Cu(I) complex was synthesized via coordination with a benzoquinoxalin‐2'‐one‐1,2,3‐triazole chelating diimine and the bis[(2‐diphenylphosphino)phenyl] ether (DPEPhos), to target a new and efficient photosensitizer for photocatalytic CO2 reduction. The Cu(I) complex absorbs in the blue‐green region of the visible spectrum, with a broad band having a maximum at 475 nm (ϵ =4500 M−1 cm−1), which is assigned to the metal‐to‐ligand charge transfer (MLCT) transition from the Cu(I) to the benzoquinoxalin‐2'‐one moiety of the diimine. Surprisingly, photo‐driven experiments for the CO2 reduction showed that this complex can undergo a photoinduced electron transfer with a sacrificial electron donor and accumulate electrons on the diimine backbone. Photo‐driven experiments in a CO2 atmosphere revealed that this complex can not only act as a photosensitizer, when combined with an Fe(III)‐porphyrin, but can also selectively produce CO from CO2. Thus, owing to its charge‐accumulation properties, the non‐innocent benzoquinoxalin‐2‐one based ligand enabled the development of the first copper(I)‐based photocatalyst for CO2 reduction. [ABSTRACT FROM AUTHOR]

The article titled "Cover Feature: Dual Role of a Novel Heteroleptic Cu(I) Complex in Visible-Light-Driven CO2 Reduction" explores the use of a CuI complex in the photocatalytic reduction of CO2. The complex serves as both a photosensitizer, transferring electrons to an iron porphyrin that reduces CO2, and a photocatalyst, directly converting CO2 to carbon monoxide. The research article provides more detailed information on this topic. The article also includes artwork by C. Bizzarri and V. Pani. [Extracted from the article]

Reaction of [Si(3,5-Me2pz)4] (1) with [Cu(MeCN)4][BF4] (2) gave the mono- and dinuclear copper complexes [Cu2(FTp*)2] (3) and [Cu(FTp*)2] (4). Both complexes contain the so-far unprecedented boron-fluorinated FTp* ligand ([FB(3,5-Me2pz)3]- with pz=pyrazolyl) originating from 1, acting as a pyrazolyl transfer reagent, and the [BF4]- counter anion of 2, serving as the source of the {BF} entity. The solid-state structures as well as the NMR and EPR spectroscopic characteristics of the complexes were elaborated. Pulsed gradient spin echo (PGSE) experiments revealed that 3 retains (almost entirely) its dimeric structure in benzene, whereas dimer cleavage and formation of acetonitrile adducts, presumably [Cu(FTp*)(MeCN)], is observed in acetonitrile. The short Cu⋯Cu distance of 269.16 pm in the solid-state is predicted by DFT calculations to be dictated by dispersion interactions between all atoms in the complex (the Cu-Cu dispersion contribution itself is only very small). As revealed by cyclic voltammetry studies, 3 shows an irreversible (almost quasi-reversible at higher scan rates) oxidation process centred at Epa=-0.23 V (E01/2=-0.27 V) (vs. Fc/Fc+). Oxidation reactions on a preparative scale with one equivalent of the ferrocenium salt [Fc][BF4] (very slow reaction) or air (fast reaction) furnished blue crystals of the mononuclear copper(II) complex [Cu(FTp*)2] (4). As expected for a Jahn-Teller-active system, the coordination sphere around copper(II) is strongly distorted towards a stretched octahedron, in accordance with EPR spectroscopic findings. [ABSTRACT FROM AUTHOR]

Reactions of the tris(3,5-dimethylpyrazolyl)methanide amido complexes [M′{C(3,5-Me2pz)3}{N(SiMe3)2}] (M′=Mg ( 1 a), Zn ( 1 b), Cd ( 1 c); 3,5-Me2pz=3,5-dimethylpyrazolyl) with two equivalents of the acidic Group 6 cyclopentadienyl (Cp) tricarbonyl hydrides [MCp(CO)3H] (M=Cr ( 2 a), Mo ( 2 b)) gave different types of heterobimetallic complex. In each case, two reactions took place, namely the conversion of the tris(3,5-dimethylpyrazolyl)methanide ligand (Tpmd*) into the -methane derivative (Tpm*) and the reaction of the acidic hydride MH bond with the M′N(SiMe3)2 moiety. The latter produces HN(SiMe3)2 as a byproduct. The Group 2 representatives [Mg(Tpm*){MCp(CO)3}2(thf)] ( 3 a/ b) form isocarbonyl bridges between the magnesium and chromium/molybdenum centres, whereas direct metal-metal bonds are formed in the case of the ions [Zn(Tpm*){MCp(CO)3}]+ ( 4 a/ b; [MCp(CO)3]− as the counteranion) and [Cd(Tpm*){MCp(CO)3}(thf)]+ ( 5 a/ b; [Cd{MCp(CO)3}3]− as the counteranion). Complexes 4 a and 5 a/ b are the first complexes that contain ZnCr, CdCr, and CdMo bonds (bond lengths 251.6, 269.8, and 278.9 pm, respectively). Quantum chemical calculations on 4 a/ b* (and also on 5 a/ b*) provide evidence for an interaction between the metal atoms. [ABSTRACT FROM AUTHOR]

Keywords: density functional theory; EPR spectroscopy; heteroacenes; UV spectroscopy; radicals EN density functional theory EPR spectroscopy heteroacenes UV spectroscopy radicals 1 1 1 04/26/22 20220422 NES 220422 B The cover feature picture shows b the successive expansion of a quinoid imidazolylidene-substituted central sulfur-containing heterocyclic core, which is accompanied by a continuous decrease in the HOMO/LUMO gap. Density functional theory, EPR spectroscopy, heteroacenes, UV spectroscopy, radicals. [Extracted from the article]

Highlights from the article: Keywords: charge transfer; hydride ligands; mass spectrometry; metal-metal interactions; photochemistry; silver The unique [Ag SB 3 sb ( SB 3 sb -H)] SP 2+ sp scaffold, featuring argentophilic interaction, was unequivocally verified by SP 1 sp H NMR spectroscopy in concert with X-ray structural analysis and DFT. Photochemistry, mass spectrometry, silver, charge transfer, hydride ligands, metal-metal interactions.