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The document is the contents list for the journal "Chemical Communications" published on September 14, 2024. It includes highlights, feature articles, and communications on various topics in chemistry. Some of the topics covered include transition metal complexes, electrochemical biosensors, and photochemical catalysis. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

Chemical reduction of a vertically expanded pentacene, TIPS-peri-pentacenopentacene (TIPS-PPP), with sodium metal in THF readily afforded a doubly-reduced product isolated as [{Na+(THF)3}2(TIPS-PPP2−)]. Single-crystal X-ray diffraction revealed the formation of a π-complex of TIPS-PPP2− with two {Na+(THF)3} moieties. The sodium ion is coordinated to three C-atoms at the most negatively charged edge sites and at the lateral ethynyl group. The delocalisation of the charge on the ethynyl function is accompanied by its notable elongation (Δ = 0.015 Å) coupled with the contraction of the adjacent single C–C bond (Δ = 0.033 Å). Bond length analysis supported by Harmonic Aromaticity Oscillator Model (HOMA) shows that the dianion can be written with four aromatic sextets in agreement with the Clar representation. Although TIPS-PPP2− has 36 π-electrons (4n), it does not show a global magnetic paratropic response. The rings with the most negative charge density have a very low paratropic response, while the other rings have a low diatropic response. Overall, the dianion is a non-aromatic molecule. [ABSTRACT FROM AUTHOR]

Electrocatalytic carbon dioxide (CO2) reduction to valuable chemical compounds is a sustainable technology with enormous potential to facilitate carbon neutrality by transforming intermittent energy sources into stable fuels. Among various electrocatalysts, metal--organic frameworks (MOFs) have garnered increasing attention for the electrochemical CO2 reduction reaction (CO2RR) owing to their structural diversity, large surface area, high porosity and tunable chemical properties. Ligands play a vital role in MOFs, which can regulate the electronic structure and chemical environment of metal centers of MOFs, thereby influencing the activity and selectivity of products. This feature article discusses the strategies for the rational design of ligands and their impact on the CO2RR performance of MOFs to establish a structure--performance relationship. Finally, critical challenges and potential opportunities for MOFs with different ligand types in the CO2RR are mentioned with the aim to inspire the targeted design of advanced MOF catalysts in the future to achieve efficient electrocatalytic CO2 conversion. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction into value-added chemicals represents an attractive and promising approach to capitalize on the abundant CO2 present in the atmosphere. This reaction, however, is hampered by low energy efficiency and selectivity owing to competition from hydrogen evolution reaction and multiple-electron transfer processes. Therefore, there is a pressing need to develop efficient yet cost-effective electrocatalysts to facilitate practical applications. Sn-based electrocatalysts have gained increasing attention in this active field due to their outstanding merits such as abundance, non-toxicity, and environmental friendliness. This review provides a comprehensive overview of recent advances in Sn-based catalysts for the CO2 reduction reaction (CO2RR), beginning with a brief introduction to the CO2RR mechanism. Subsequently, the CO2RR performance of various Sn-based catalysts with different structures is discussed. The article concludes by addressing the existing challenges and offering personal perspectives on the future prospects in this exciting research area. [ABSTRACT FROM AUTHOR]

A highly rigid amine-linked 3D COF was constructed from two orthogonal building blocks (spirobifluorene and bicarbazole) through a post-synthetic chemical reduction. The rigid 3D framework decreased the conformational flexibility of the amine linkages, and thus showed a fully preserved crystallinity and porosity. The amine moieties in the 3D COF afforded abundant chemisorptive sites for selectively capturing CO2. [ABSTRACT FROM AUTHOR]

Reduction of the heteroleptic Ln(III) precursors [Ln(Tp)2(OTf)] (Tp = hydrotris(1-pyrazolyl)borate; OTf = triflate) with either an aluminyl(I) anion or KC8 yielded the adduct-free homoleptic Ln(II) complexes dimeric 1-Eu [{Eu(Tp)(μ-κ1:η5-Tp)}2] and monomeric 1-Yb [Yb(Tp)2]. Complexes 1-Ln have good solubility and stability in both non-coordinating and coordinating solvents. Reaction of 1-Ln with 2 Ph3PO yielded 1-Ln(OPPh3)2. All complexes are intensely coloured and 1-Eu is photoluminescent. The electronic absorption data show the 4f–5d electronic transitions in Ln(II). Single-crystal X-ray diffraction data reveal first μ-κ1:η5-coordination mode of the unsubstituted Tp ligand to lanthanides in 1-Eu. [ABSTRACT FROM AUTHOR]

Pillar[5]arene-functionalized rhodium nanoparticles (Rh@CPA NPs) are first synthesized via a facile one-pot chemical reduction method. Rh@CPA NPs with good reusability and biocompatibility show excellent catalytic activities in reducing toxic nitrophenols and azo dyes, and also exhibit superior photothermal ablation capability towards Staphylococcus aureus under 808 nm laser irradiation. This work suggests that the supramolecular capping strategy could be used to construct novel hybrid materials for various applications. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction reaction (NitRR) is an energy-saving and environmentally benign approach to synthesizing ammonia under ambient conditions. However, the development of noble metal-free catalysts with high activity and selectivity is still a significant challenge. In this study, uniformly dispersed amorphous CoBx nanoparticles supported on carbon paper were synthesized VIA a simple wet chemical reduction method. As an efficient nitrate reduction electrocatalyst, CoBx exhibited a maximum faradaic efficiency of 94.00 ± 1.67% and a yield rate of up to 0.787 ± 0.028 mmol h−1 cm−2 for ammonia production. The enhanced NitRR performance could be attributed to a partial electron transfer from B to Co, which is necessary for optimizing the adsorption energies of the reaction intermediates and facilitating electron transport. Thus, selective and cost-effective electroreduction of nitrates to ammonia can be achieved using CoBx nanoparticles. [ABSTRACT FROM AUTHOR]

A novel redox-active fluorene monomer is synthesized and copolymerized with 9,9-dioctylfluorene and benzo[c][1,2,5]thiadiazole via Suzuki cross-coupling to produce alternating and tertiary copolymers. Electrochemical and chemical reduction of the copolymers generates organic polymeric radical anions. Electrochemical, spectroscopic, and photophysical characterization grant insight into the structure–property relationship for open-shell conjugated polymers. [ABSTRACT FROM AUTHOR]

The chemical reduction of a corannulene-based molecular nanographene, C76H64 (1), with Na metal in the presence of 18-crown-6 afforded the doubly-reduced state of 1. This reduction provokes a distortion of the helicene core and has a significant impact on the aromaticity of the system. [ABSTRACT FROM AUTHOR]

The chemical reduction of a π-expanded COT derivative, octaphenyltetrabenzocyclooctatetraene (1), with lithium or sodium metals in the presence of secondary ligands affords a new doubly-reduced product (1TR2−). The X-ray diffraction study revealed a reductive core rearrangement accompanied by the formation of a single C–C bond and severe twist of the central tetraphenylene core. The reversibility of two-electron reduction and core transformation is further confirmed by NMR spectroscopy and DFT calculations. [ABSTRACT FROM AUTHOR]

Preliminary chemical reduction of naphthalenediimide (NDI)-based organic ligands was applied to the synthesis of a porous molecular conductor (PMC) with neutral metal nodes (cobalt(II) acetylacetonate). The obtained semiconductive PMC (PMC-2) was stable due to the neutral metal nodes, providing an advantage over electrochemical reduction. [ABSTRACT FROM AUTHOR]

A flexible coordination polymer with a naphthalenediimide core exhibited reversible desorption–adsorption of solvent molecules and an enhancement of electrical conductivity (∼10−7 S cm−1) upon chemical reduction using hydrazine. [ABSTRACT FROM AUTHOR]

Successive chemical reductions of the heteroleptic complex [(tpy)CrIII(tphz)]3+ (tpy = terpyridine; tphz = tetrapyridophenazine) give rise to the mono- and di-radical redox isomers, [(tpy)CrIII(tphz˙−)]2+ and [(tpy˙−)CrIII(tphz˙−)]+, respectively. As designed, the optimized overlap of the involved magnetic orbitals leads to extremely strong magnetic interactions between the S = 3/2 metal ion and S = 1/2 radical spins, affording well isolated ST = 1 and ST = 1/2 ground states at room temperature. [ABSTRACT FROM AUTHOR]

We present the preparation of a nitrogen-based bidentate ligand featuring an appended boron Lewis acid as well as its tetrahedral Fe2+ and Zn2+ complexes. These complexes act as platforms for hydrazine and hydroxylamine capture and reduction chemistry. [ABSTRACT FROM AUTHOR]

Selective reduction of 1,5-diazacyclooctatetraenes with potassium or a Co(i) complex was achieved to provide the first structurally well-defined aromatic 1,5-diazacyclooctatetraenyl dianion or a novel dinuclear Co(ii) complex bridged by a bipyrrolinyl dianion, respectively. [ABSTRACT FROM AUTHOR]

H2S is considered to be an important reductant in abiotic CO2 reduction to organics, however, almost no experimental support has been reported. Herein, the first observation of CO2 reduction to formate with H2S under alkaline hydrothermal conditions is reported, and water is found to act as a hydrogen donor. [ABSTRACT FROM AUTHOR]

A novel and efficient method is demonstrated to improve the electrochemical performance of Li4Ti5O12 and metal-oxide anodes. In contrast to other methods, inexpensive red phosphorus powder is used as a reducing reagent, and the reduction is conducted at a relatively low temperature of 400 °C. This method offers a low cost and effective way for Li4Ti5O12 and metal-oxide anode applications. [ABSTRACT FROM AUTHOR]

A spiro-fused hexa-peri-hexabenzocoronene dimer was synthesized, and its physicochemical properties were studied by UV-Vis absorption and emission spectroscopy as well as cyclic voltammetry. Chemical oxidation of SB-HBC afforded its radical cation and dication derivatives, which could be reversibly reduced to the neutral state. [ABSTRACT FROM AUTHOR]

The two electron reduction of iron complexes [(PRP2Cy)Fe(Cl)2] (R = Ph or tBu) 2a–b afforded complexes [(PRP2Cy)Fe(N2)2] 4a–b. Protonation of 4a at the metal center and subsequent reduction to Fe(i)–H species lead to complex [(PPhP2Cy)Fe(N2)(H)2] 6avia a spontaneous disproportionation reaction. Complex 4a behaves as one of the most efficient monometallic Fe-catalysts reported to date for N2-to-N(SiMe3)3 functionalization under atmospheric pressure. [ABSTRACT FROM AUTHOR]

In this work, we decorated the surface of MSNs by a one-pot Passerini reaction using near-infrared fluorescence BODIPY and poly(ethylene glycol) with an aldehyde group (PEG-CHO) for the first time. Doxorubicin (Dox) was loaded to demonstrate the reduction response. The formed MSNs neatly integrate chemotherapy, photothermal therapy and near-infrared fluorescence (NIRF) imaging. [ABSTRACT FROM AUTHOR]

In this communication, a novel reductive dl-mandelic acid loading approach for moisture-stable Mn4+ doped fluorides is reported. After loading dl-mandelic acid, the characteristic luminescence properties of the treated Mn4+ doped potassium hexafluorogermanate remained unchanged, while the moisture-resistance property was significantly enhanced. [ABSTRACT FROM AUTHOR]

Lead halide perovskites (LHPs) have been investigated for photoelectrochemical hydrogen generation from water splitting. However, the harsh requirements in preparing the environment, i.e. isolating water and oxygen, hinder the wide applications of lead halide perovskites. Herein, an all-inorganic perovskite, i.e. a CsPbBr3-based photocathode, has been prepared to generate hydrogen. It is notable that as a valuable trial for a potential large-scale production, the whole preparation process was completed in an open-air environment. The LHP photocathode achieved the highest photocurrent of about 1.2 mA cm−2 at 0 VRHE. And the photocurrent remains around 94% after continuous illumination for 1 h with the Faradaic efficiency of 90%, illustrating a good photoelectrochemical stability. The all-inorganic LHP photocathodes are facile to prepare with a relatively good performance, and can be improved via band engineering and structure optimization, of which large-scale applications can be expected. [ABSTRACT FROM AUTHOR]

We succeeded in controlling the crystal structure of osmium (Os) nanoparticles (NPs). Although Os adopts only a hexagonal close-packed (hcp) structure in the bulk state, a face-centred cubic (fcc) Os was synthesized by a chemical reduction method using an Os acetylacetonate complex as a precursor. [ABSTRACT FROM AUTHOR]

Oxo group activation with reduction of neptunyl(vi) and plutonyl(vi) to tetravalent hydroxo species by the hydroxypyridinone siderophore derivative 3,4,3-LI-(1,2-HOPO) was investigated in the gas-phase via electrospray ionization mass spectrometry, in solution via Raman spectroscopy, and computationally via density functional theory. Dissociation of the gas-phase tetravalent complexes resulted in actinide–hydroxo bond cleavage. [ABSTRACT FROM AUTHOR]

The dinuclear SmII complex, [Sm2L4(dme)] (L = OSi(OtBu)3), is easily obtained from the protonolysis reaction of [Sm{N(SiMe3)2}(thf)2] with HOSi(OtBu)3. This complex reacts slowly with toluene, resulting in the isolation of the triple-decker arene-bridged SmII complex, [{Sm2L3}2(μ-η6:η6-C7H8)], in 44% yield. This reactivity provides the first example of unambiguous arene reduction by an isolated SmII species. In contrast, reduction of [SmL3]2 afforded the inverse sandwich complex, [{KSmL3}2(μ-η6:η6-C7H8)]. [ABSTRACT FROM AUTHOR]

A carbene-stabilised neutral boryl radical and a boryl anion are isolated via selective one- and two-electron reduction of a diamidocarbene (DAC) adduct of dibromo(pentafluorophenyl)borane. Both the radical and the anion have been characterised by various spectroscopic techniques in solution, while the structures have been ascertained by single-crystal X-ray diffraction. In contrast, the reduction of the analogous cyclic (alkyl)(amino) carbene (CAAC) adduct yields a C–H activation product. [ABSTRACT FROM AUTHOR]

A reduction of quinolines to synthetically versatile tetrahydroquinoline molecules with I2 and HBpin is described. In the presence of iodine (20 mol%) as a catalyst, reduction of quinolines and other N-heteroarenes proceeded readily with hydroboranes as the reducing reagents. The broad functional-group tolerance, good yields and mild reaction conditions imply high practical utility. [ABSTRACT FROM AUTHOR]

Well-dispersed nanostructured catalysts along mesoporous materials have been systematically prepared via a novel multistep approach involving either the pyrolysis under nitrogen, the calcination under oxygen or the reduction under hydrogen of MOF nanocrystals decorated with transition metal complexes and previously confined within the mesoporous cavities via novel solid state synthesis. The resulting supported nanostructured catalysts can be composed of metals, metal oxides, heteroatom-doped carbons and combinations thereof depending on the transformation conditions. The pioneering concept of Fluidized-Nanoreactor Hydrogen Carriers has been proposed for the first time by using the resulting nanostructured catalysts within fluidized mesoporous silica. [ABSTRACT FROM AUTHOR]

Here, we report a synthesis of Cu nanocubes by photoreduction of CuSO4. Because synthetic saponite (one of the layered clay minerals) was used as the adsorbent, the nanocubes contained no capping agents or protectants, and the disproportionation reaction of Cu2O with H2SO4 was found to be the key for morphological control. [ABSTRACT FROM AUTHOR]

An X-ray diffraction study of [6]cycloparaphenylene (1), crystallized under solvent-free conditions, revealed a unique solid state structure with tight packing of individual molecules that minimizes empty internal space. The controlled chemical reduction of this highly strained nanohoop with Group 1 metals resulted in the first isolation and structural characterization of its mono- and dianions, allowing for the evaluation of core transformations for the series ranging from 10 to 11− and 12−. [ABSTRACT FROM AUTHOR]

At least two distinct processes occur during heating of the copper-exchanged mordenite in oxygen-free environment depending on the sample synthesis procedure. The first process corresponds to the reaction of Cu(ii) sites with the residual traces of carbonaceous impurities left in the sample after the synthesis without calcination in an oxidant-containing environment, yielding Cu(i) and carbon dioxide. The second relates to autoreduction of Cu(ii) into Cu(i) species accompanied with the release of molecular oxygen. The results show that to completely remove all traces of carbonaceous impurities and to avoid the loss of the active Cu(ii) sites during the activation, copper-exchanged zeolite samples should be calcined in oxidative gases at elevated temperature and, preferentially, prior to the experiments to avoid the adsorption of organic compounds from air. [ABSTRACT FROM AUTHOR]

We report in situ atomic-scale transmission electron microscopy observations of the surface dynamics during Cu2O reduction. We show inhomogeneous oxide reduction caused by the preferential adsorption of hydrogen at step edges that induces oxygen loss and destabilizes Cu atoms within the step edge, thereby resulting in the retraction motion of atomic steps at the oxide surface. [ABSTRACT FROM AUTHOR]

Herein we report a straightforward synthesis of an ultrathin protein-iron(ii) carbonate nanorods (FeCO3-NRs) heterogeneous bionanohybrid at room temperature and in aqueous media. The enzyme induced the in situ formation of well-dispersed FeCO3 NRs on a protein network. The addition of NaBH4 as a reducing agent allowed us to obtain nanorods (5 × 40 nm) with superparamagnetic properties. This bionanohybrid showed excellent catalytic results in reduction, oxidation and C–C bond reactions. [ABSTRACT FROM AUTHOR]

Photoredox cycling during UV irradiation of ferrocyanide ([FeII(CN)6]4−) in the presence of stoichiometric sulfite (SO32−) is shown to be an extremely effective way to drive the reductive homologation of hydrogen cyanide (HCN) to simple sugars and precursors of hydroxy acids and amino acids. [ABSTRACT FROM AUTHOR]

Reduction of a variety of organo halides was examined by using amines as a sacrificial hydrogen source. UV light-induced reduction of vinyl and aryl halides with triethylamine proceeded smoothly to give the corresponding reduced products. High temperature heating also caused the reduction and DABCO (1,4-diazabicyclo[2.2.2]octane) also served as a good reducing reagent. [ABSTRACT FROM AUTHOR]

A novel gel electrolyte approach has been implemented to enable the electrochemical reduction of nitrogen to ammonia at low temperature and pressure. [ABSTRACT FROM AUTHOR]

A copper(i)-catalysed asymmetric allylic reduction enables a regio- and stereoselective transfer of a hydride nucleophile in an SN2′-fashion onto allylic bromides. This transformation represents a conceptually orthogonal approach to allylic substitution reactions with carbon nucleophiles. A copper(i) complex based upon a chiral N-heterocyclic carbene (NHC) ligand allows for stereoselectivity reaching 99% ee. The catalyst enables a stereoconvergent reaction irrespective of the double bond configuration of the starting materials. [ABSTRACT FROM AUTHOR]

A simple chemical process was developed in a scalable manner, to reduce trap states in perovskite absorbers from the very beginning. The obvious decrease of I2 in methylammonium iodide and the decrease of trap density in the resultant films were identified, which led to the power conversion efficiency (PCE) of perovskite solar cells (PSCs) increase from 16.5% to 18.5%. [ABSTRACT FROM AUTHOR]

An elegant synthetic route to a ladder-type di-borate compound 2a was reported based on the reduction, radical-cyclization, and oxidative-dehydrogenation reaction of 1. The existence of the biradical intermediate [1ṖṖ]2− was supported by both EPR measurements and DFT calculations. [ABSTRACT FROM AUTHOR]

SiCl4 can be directly reduced to nano-Si with commercial Na metal under solvent-free conditions by mechanical milling. Crystalline nano-Si with an average size of 25 nm and quite uniform size distribution can be obtained, which shows excellent lithium storage performance, for a high reversible capacity of 1600 mA h g−1 after 500 cycles at 2.1 A g−1. [ABSTRACT FROM AUTHOR]

The pyridine-rich complex [NiII(LN2Py3)(MeCN)](ClO4)2 (1) acts as an efficient electro- and photocatalyst in the generation of H2 from water. Observed TONs reach 1050 for electrocatalysis and a remarkable 3500 for photocatalysis. Experimental and DFT data support the ligand-reduced [NiILṖ] as the catalytically active species, contrasting with the [CoIL] observed for cobalt catalysts. [ABSTRACT FROM AUTHOR]

Magnesium bis(hydridotriphenylborate), isolated as a solvent-separated ion pair [Mg(thf)6][HBPh3]2, effectively catalyzed the hydroboration of several unsaturated substrates including CO2. [ABSTRACT FROM AUTHOR]

The radical anion and dianion of tridecacyclene (C48H24, 1) have been prepared by reduction with potassium metal. Analysis of the solid-state structure of the dipotassium salt of the dianion (3) reveals evidence of increased aromatic character within the structure's central 8-membered ring despite preservation of the tub-like shape inherent to its neutral parent. [ABSTRACT FROM AUTHOR]

Herein, we report a one-step synthesis method for octahedral Pt–Ni–Co ternary catalysts with tunable compositions and fixed shapes. Impressively, the composition optimized octahedral PtNi0.55Co0.1/C demonstrated a significant improvement in ORR activity compared to those of previously reported Pt–Ni–Co alloy octahedra, showing an outstanding specific activity of 5.05 mA cm−2 and a mass activity of 2.80 mA μgPt−1, which are around 20.2 times and 14.7 times higher than those of the commercial Pt/C catalyst (0.25 mA cm−2 and 0.19 mA μgPt−1). [ABSTRACT FROM AUTHOR]

We report a one-step procedure for the preparation of N-(2-pyrrole)-sulfonamides from sulfonamides and pyrroles. The reaction uses visible light, an acridinium dye as photocatalyst and oxygen as the terminal oxidant for the oxidative C–N bond formation; structures of several reaction products were confirmed by X-ray structure analysis. The reaction is selective for pyrroles, due to the available oxidation power of the photocatalyst and the required stability of the carbocation intermediate under the reaction conditions. [ABSTRACT FROM AUTHOR]

3D multi-stacked hyperporous silicon flakes (MHSFs) are prepared via a selective chemical reduction of natural clay minerals bearing MgO negative catalyst layers. The resultant MHSFs are used as a photocatalyst for solar-driven hydrogen evolution and exhibit the highest photocatalytic acitivty (1031 μmol H2 h−1 g−1 Si) coupled with a Pt cocatalyst. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate that Zn-MOF-74 enables the ultrafast and one-step generation of the Fe2O3@MOF composite once Zn-MOF-74 contacts with FeSO4 solution. This unique reaction can be further applied in catalysis of U(vi) reduction by Fe(ii) under ambient conditions. The results provide a highly renovated strategy for U(vi) reduction by Fe(ii) just under ambient conditions, which completely subvert all established methods about U(vi) reduction by Fe(ii) in which O2- and CO2-free conditions are absolutely required. [ABSTRACT FROM AUTHOR]