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Exploration of the reduction chemistry of the 2,2'‐bipyridine (bipy) lanthanide metallocene complexes Cp*2LnCl(bipy) and Cp*2Ln(bipy) (Cp* = C5Me5) resulted in the isolation of a series of complexes with unusual composition and structure including complexes with a single Cp* ligand, multiple azide ligands, and bipy ligands with close parallel orientations. These results not only reveal new structural types, but they also show the diverse chemistry displayed by this redox‐active platform. Treatment of Cp*2NdCl(bipy) with excess KC8 resulted in the formation of the mono‐Cp* Nd(III) complex, [K(crypt)]2[Cp*Nd(bipy)2], 1, as well as [K(crypt)][Cp*2NdCl2], 2, and the previously reported [K(crypt)][Cp*2Nd(bipy)]. A mono‐Cp* Lu(III) complex, Cp*Lu(bipy)2, 3, was also found in an attempt to make Cp*2Lu(bipy) from LuCl3, 2 equiv. of KCp*, bipy, and K/KI. Surprisingly, the (bipy)1− ligands in neighboring molecules in the structure of 3 are oriented in a parallel fashion with intermolecular C⋅⋅⋅C distances of 3.289(4) Å, which are shorter than the sum of van der Waals radii of two carbon atoms, 3.4 Å. Another product with one Cp* ligand per lanthanide was isolated from the reaction of [K(crypt)][Cp*2Eu(bipy)] with azobenzene, which afforded the dimeric Eu(II) complex, [K(crypt)]2[Cp*Eu(THF)(PhNNPh)]2, 4. Attempts to make 4 from the reaction between Cp*2Eu(THF)2 and a reduced azobenzene anion generated instead the mixed‐valent Eu(III)/Eu(II) complex, [K(crypt)][Cp*Eu(THF)(PhNNPh)]2, 5, which allows direct comparison with the bimetallic Eu(II) complex 4. Mono‐Cp* complexes of Yb(III) are obtained from reactions of the Yb(II) complex, [K(crypt)][Cp*2Yb(bipy)], with trimethylsilylazide, which afforded the tetra‐azido [K(crypt)]2[Cp*Yb(N3)4], 6, or the di‐azido complex [K(crypt)]2[Cp*Yb(N3)2(bipy)], 7 a, depending on the reaction stoichiometry. A mono‐Cp* Yb(III) complex is also isolated from reaction of [K(crypt)][Cp*2Yb(bipy)] with elemental sulfur which forms the mixed polysulfido Yb(III) complex [K(crypt)]2[Cp*Yb(S4)(S5)], 8 a. In contrast to these reactions that form mono‐Cp* products, reduction of Cp*2Yb(bipy) with 1 equiv. of KC8 in the presence of 18‐crown‐6 resulted in the complete loss of Cp* ligands and the formation of [K(18‐c‐6)(THF)][Yb(bipy)4], 9. The (bipy)1− ligands of 9 are arranged in a parallel orientation, as observed in the structure of 3, except in this case this interaction is intramolecular and involves pairs of ligands bound to the same Yb atom. Attempts to reduce further the Sm(II) (bipy)1− complex, Cp*2Sm(bipy) with 2 equiv. of KC8 in the presence of excess 18‐crown‐6 led to the isolation of a Sm(III) salt of (bipy)2− with an inverse sandwich Cp* counter‐cation and a co‐crystallized K(18‐c‐6)Cp* unit, [K2(18‐c‐6)2Cp*]2[Cp*2Sm(bipy)]2 ⋅ [K(18‐c‐6)Cp*], 10. [ABSTRACT FROM AUTHOR]

This paper explores the interaction of divalent [Sm(DippForm)2(thf)2] with substrates containing azo linkages. Treatment of [Sm(DippForm)2(thf)2] with trans‐azobenzene results in formation of mononuclear [Smlll(DippForm)2(Ph2N2)(thf)] ⋅ 3THF (1) or dinuclear [Smlll(DippForm)(Ph2N2)(thf)]2 ⋅ 4THF (2) and [Sm(DippForm)3] depending on the reaction stoichiometry, where azobenzene has undergone either a one or two electron reduction. These reactions parallel the corresponding reactions of [Sm(C5Me5)2(thf)2], but the coordination of [N2Ph2]− in 1 differs significantly from that of {Sm(C5Me5)2(Ph2N2)(thf)}. On the other hand, the structure of 2 is similar to that of the pentamethylcyclopentadienyl analogue. The reaction of [Sm(DippForm)2(thf)2] with 1H‐1,2,3‐benzotriazole also yielded a trivalent samarium complex containing benzotriazolate (btz), [Smlll(DippForm)2(btz)(thf)] ⋅ THF (3), and suggests more utilization of 1H‐1,2,3‐benzotriazole in divalent lanthanoid reduction chemistry is possible. [ABSTRACT FROM AUTHOR]

The complex [Mn(bpy)(CO)3Br], has been previously studied as both an electrocatalyst and a photocatalyst, in conjugation with a photosensitizer, for CO2 reduction to CO. This study considers the relationship between this catalytic activity and the steric and electronic nature of the aromatic diimine ligand. To this end, the π‐system in the bidentate ligand is increased step‐wise from 2,2′‐bipyridine (bpy) to 2‐(2‐pyridyl)quinoline (pq) to 2,2′‐biquinoline (bqn) in a series of three fac‐[Mn(α‐diimine)(CO)3Br] complexes. It is found that the propensity of these complexes to photochemically dimerize trends with the energy of the α‐diimine π* energy. Electrochemically, it is observed that the second reduction event in these systems becomes increasingly thermodynamically favorable and approaches the potential of the first reduction event as the π‐system expands. In fac‐[Mn(bqn)(CO)3Br], the second reduction is more favorable than the first reduction, precluding the formation of a dimer intermediate; even though, chemical reduction of fac‐[Mn(bqn)(CO)3Br] confirms that the dimer, [Mn(bqn)(CO)3Br]2 is able to form and not prevented by steric considerations. Though the second reduction potential is more positive for bqn and pq than for bpy, the CO2 reduction mechanism changes such that the overpotential for carbon dioxide reduction occurs at more negative potentials, leading to a decrease in overall catalytic activity. [ABSTRACT FROM AUTHOR]

A novel nanocomposite (TNTs‐FeS) was developed by anchoring ferrous sulfide (FeS) nanoparticles immobilized on titanate nanotubes (TNTs) by hydrothermal method to remove U(VI) and Re(VII) from aqueous solution, and the removal mechanism and efficiency were examined. The experimental results showed that the TNTs can effectively improve the dispersibility and stability of FeS. The environmental conditions, including initial solution pH, initial concentration, equilibrium time, and dosage, played an important role in the remediation process, which can affect the immobilization efficiency significantly. The maximum quantity removal of U(VI) and Re(VII) was 291.67 and 226.23 mg/g at pH of 6.0 and 12.0. The adsorption kinetics and the equilibrium isotherms of U(VI) and Re(VII) all fitted well with the pseudo‐second‐order model (R2>0.99) and the Freundlich model (R2>0.99). The main mechanism of removal by TNTs‐FeS was electrostatic attraction, chemical reduction, and surface complexation. Thus, TNTs‐FeS composites exhibited a high potential to remove U(VI) and Re(VII) heavy metal ions from the surface and groundwater. [ABSTRACT FROM AUTHOR]

Technetium‐99 is a prevalent fission product from nuclear waste. The long half‐life (211,000 yr) and environmental mobility of pertechnetate (TcO4−) render Tc particularly challenging to isolate and stabilize. Here we present two approaches for development of potential wasteforms using titanium dioxide, TiO2. Approach 1 is a low temperature chemical synthesis of TiO2 doped with Tc(IV) from TcO4− intended to mimic the Tc waste stream from the UREX family of separations and removes 98.5 % of the Tc, mainly present as edge‐shared Tc(IV) pairs. Approach 2 utilizes TiO2 to photocatalytically reduce TcO4− to Tc(IV) stabilized on the surface of or within the TiO2 lattice. The %Tc removed from solution and adsorbed to TiO2 is pH dependent, with the maximum Tc(IV) adsorbed at pH 3–4 as either TcO2 or edge‐sharing Tc(IV) octahedra. The Tc(IV)‐TiO2 composites materials formed by both approaches are suitable for consolidation into a dense wasteform by Hot Isostatic Pressing (HIPing). [ABSTRACT FROM AUTHOR]

An iridium complex [H(dmso)2]2[IrCl6] (1) is synthesized via the reaction of H2IrCl6 with DMSO in an acetone solution. The substance is thoroughly characterized using UV‐Vis, ATR‐FTIR, NMR, and EPR spectroscopies, single‐crystal and powder X‐ray diffraction. Iridium undergoes a slow spontaneous reduction to the chemical state +3 when solutions of 1 in water, hydrochloric acid, or acetone (CIr=n ⋅ 10−2−n ⋅ 10−4 M) are allowed to age in ambience. In the case of acetone solutions, the reduction is accompanied by the incorporation of DMSO molecules into the coordination sphere of Ir giving rise to trans‐[IrIIICl4(dmso)2]−. In parallel, protonated DMSO shows reactivity towards acetone to afford dimethylacetonylsulfonium cations. Red crystals of [Me2SCH2C(O)Me]2[IrCl6] (2), orange crystals of [Me2SCH2C(O)Me][IrCl4(dmso)2] (3), and yellow crystals of [H(dmso)][IrCl4(dmso)2] (4) were isolated from aged acetone solutions of 1 and studied by X‐ray crystallography. In the crystal structures of 2 and 3, dimethylacetonylsulfonium act as the cationic parts of the complexes. Meanwhile, the protonated form of DMSO, hydroxy(dimethyl)sulfonium, is found in 4. A similar aging procedure applied to an acetone solution of Os‐based analogue [H(dmso)2]2[OsCl6] afforded a novel osmium complex [Me2SCH2C(O)Me]2[OsCl6] (5), which was proven to be isostructural to 2. [ABSTRACT FROM AUTHOR]

The splitting of N2 into well‐defined terminal nitride complexes is a key reaction for nitrogen fixation at ambient conditions. In continuation of our previous work on rhenium pincer mediated N2 splitting, nitrogen activation and cleavage upon (electro)chemical reduction of [ReCl2(L2)] {L2 = N(CHCHPtBu2)2–} is reported. The electrochemical characterization of [ReCl2(L2)] and comparison with our previously reported platform [ReCl2(L1)] {L1 = N(CH2CH2PtBu2)2–} provides mechanistic insight to rationalize the dependence of nitride yield on the reductant. Furthermore, the reactivity of N2 derived nitride complex [Re(N)Cl(L2)] with electrophiles is presented. [ABSTRACT FROM AUTHOR]

Front Cover: A Tetrapodal Penta-Carbene Ligand and Iron(III) Complex (Eur. J. Inorg. Keywords: Carbene ligands; Iron; Magnetic properties; Structure elucidation; Tetrapodal pentadentate complexes EN Carbene ligands Iron Magnetic properties Structure elucidation Tetrapodal pentadentate complexes 1 1 1 07/18/23 20230713 NES 230713 B The Front Cover b shows selected tetrapodal-pentadentate "butterflies" taking flight. Carbene ligands, Iron, Magnetic properties, Structure elucidation, Tetrapodal pentadentate complexes. [Extracted from the article]

A 1:1 complex of a 2,6‐bis‐tetrazinylpyridine pincer ligand, btzp, with ZnCl2 is characterized. The molecule is shown to be redox active by cyclic voltammetry and by chemical reduction. The resulting monoanion loses chloride to yield a radical species [Zn(btzp)Cl] whose EPR spectrum is observed. DFT studies show that the electron added upon reduction goes into an orbital primarily comprised of tetrazine nitrogen pπ character. The Zn–Cl bonds lengthen but the Zn–Ntz bonds shorten upon reduction, in response to taking on amide character. In an alternative approach to evaluating the electron accepting capacity of btzp, the molecule [Ru(btzp)Cl2(CO)] has been fully characterized and shows a CO stretching frequency 84 cm–1 higher than that of its terpyridine analog. This result indicates btzp is strongly electron withdrawing; the CO stretching frequency for [Ru(btzp)Cl2(CO)] is among the highest ever observed for a ruthenium(II) monocarbonyl complex. Computational experiments on [Ru(btzp)Cl2(L)] test the influence of L on π‐back donation to btzp. [ABSTRACT FROM AUTHOR]

The chemistry of diiron complexes has seen a recent renaissance, due to the prominent role played by the element iron in the development of sustainable synthetic processes and the cooperative effects provided by two metal centers working in concert, that is a concept amazingly exploited by Nature. Aminoalkylidyne derivatives of [Fe2Cp2(CO)4] are a convenient scaffold to grow organic fragments; in particular, the facile removal of one CO ligand opens the doors to the unconventional assembly of molecules/ions, affording unusual structural motifs. In particular, vinyliminium complexes result from carbyne–alkyne coupling and offers the opportunity for a great variety of selective derivatization pathways, including addition of nucleophiles, access to substituted ferrocenes, deprotonation and reduction processes, and trapping of small molecules. [ABSTRACT FROM AUTHOR]

This study reports that aquahydroxocobinamide [(H2O)(HO–)Cbi(III)], a nucleotide‐free analogue of cobalamin (vitamin B12; Cbl), is capable of catalyzing the reduction of the two‐electron oxidized form of vitamin C, dehydroascorbic acid (DHA), to ascorbic acid by glutathione (GSH), whereas catalytic quantities of aquacobalamin do not accelerate the reaction. This observation is explained by different reactions taking place with the CoIII‐species of these complexes and GSH: Cbl(III) forms a stable complex with GSH, but Cbi(III) is relatively rapidly reduced to Cbi(II). The reaction of Cbi(II) with DHA in the presence of GSH includes the coordination of GSH onto CoII, the reaction of GS––Cbi(II) with DHA produces GS––Cbi(III) and the ascorbyl radical, which rapidly disproportionates to a mixture of ascorbic and dehydroascorbic acids, and further regeneration of Cbi(II). [ABSTRACT FROM AUTHOR]

The reduction ability of a N→Sn coordinated distannyne {LSn}2, where L is [C6H3‐2,6‐(Me2NCH2)2]– is tested towards organic molecules ethylene and cyclooctatetraene. These reactions provide the compound [{LSn}3SnH] (2), as the result of a hydride abstraction. DFT calculations suggest that compound 2 can be interpreted as highly covalently bonded {HSnI} and {(SnIL)3} fragments. While the reduction of the C=C bond is not observed in the reaction of 1 with organic molecules, the reducing ability of 1 is observed in the reaction with inorganic SnO. Complex 1 is able to reduce SnO and the organotin(II) oxide {LSn}2O (3) is obtained. Moreover, compound 3 is able to coordinate an excess of SnO to yield the organotin(II)–tin(II)–oxo cluster L4Sn10O8 (4). [ABSTRACT FROM AUTHOR]

Two copper-based Cu3(btc)2 and Cu(Im)2 metal-organic frameworks are synthesized and annealed to form nanoporous Cu/Cu2O@C and Cu@N-C nanoparticles for utilization as catalysts in the reduction reaction of aromatic nitro compounds to aromatic amines. All synthesized MOF compounds and MOF-derived nanoparticles are characterized using XRD, Raman spectroscopy, TGA, SEM-EDX, and XPS methods. Also, the pore-size distribution and surface area of the MOF-derived Cu/Cu2O@C and Cu@N-C nanoparticles are characterized by the BJH and BET methods. After characterization, the catalysts Cu/Cu2O@C and Cu@N-C are catalytically tested for the reduction reactions of various aromatic nitro compounds chemically by monitoring with a UV/Vis spectrometer. Both catalysts exhibit remarkable results compared with those in the literature. Also, the Cu/Cu2O@C catalyst shows better results than the Cu@N-C catalyst. [ABSTRACT FROM AUTHOR]

Two new trinuclear compounds [{Ni(xbSmS)}2Ru-(phen)2](PF6)2 (1) and [{Ni(xbSmSe)}2Ru(phen)2](PF6)2 (2) were synthesized by the reaction of [Ni(xbSmS)] and [Ni(xbSmSe)], respectively, with cis-[Ru(phen)2(Cl)2][H2xbSmS = 1,2-bis(4-mercapto-3,3-dimethyl-2-thiabutyl)benzene; H2xbSmSe = 1,2-bis(2-thiabutyl-3,3-dimethyl-4-selenol)benzene; phen = phenanthroline]. The two [Ni2Ru] complexes were characterized by ESI-MS, NMR spectroscopy, elemental analysis, single-crystal X-ray crystallography, and electrochemical techniques. X-ray structure determinations showed that the trinuclear complex cations in 1 and 2 contain two square-planar nickel centers bound in cis positions to the octahedral ruthenium ion by a bridging thiolate or selenolate donor atom. Electrocatalytic proton reduction occurs for both complexes in acetonitrile with the addition of varying amounts of acetic acid at a potential of -2.1 V vs. Fc+/Fc with faradaic yields of around 65%. [ABSTRACT FROM AUTHOR]

An efficient, green, and reusable system comprising gold nanoparticles entrapped in an organically modified sol-gel silica matrix was found to catalyze the reduction of monobromo- and tribromoacetic acid by NaBH4. Interestingly, the reduction of tribromoacetic acid yielded succinic acid along with acetic acid, whereas monobromoacetic acid was reduced only to acetic acid. The relative yields of succinic acid and acetic acid depended on the rate of addition of BH4 -. Slow addition resulted in the formation of succinic acid as the major product. A variable product distribution was achieved as a result of the different pathways for dehalogenation. [ABSTRACT FROM AUTHOR]

For the first time, the potential of noble-metal-free iron-based photosensitizers for photocatalytic water reduction by using homo- and heteroleptic carbene complexes was proven. The development of a facile synthesis route for such carbene complexes was delineated. The complexes were investigated by UV/Vis and fluorescence spectroscopy, DFT calcula-tions, cyclic voltammetry, and X-ray absorption spectroscopy. Their catalytic performance was compared to that of established noble-metal-containing photosensitizers such as [Ir(ppy)2(bpy)][PF6] (Hppy = 2-phenylpyridine, bpy = 2,2'-bipyridine). [ABSTRACT FROM AUTHOR]

The α-phosphanylferrocenecarbaldehyde ( pS)- 1 was converted into the β-styryl derivative ( pS)- 4 by Wittig-Horner olefination. Subsequent hydroboration with Piers' borane [HB(C6F5)2] followed by H2 splitting and crystallization gave the phosphonium/hydridoborate product ( pS, R)- 5, which was used as a frustrated Lewis pair catalyst for the asymmetric hydrogenation of a series of imines (up to 69 % ee). [ABSTRACT FROM AUTHOR]

Mono- and bis(guanidine) ligands stabilise bis-µ-oxido dicopper(III) complexes. Here, the formation of these complexes has been investigated in detail by means of low-temperature stopped-flow techniques for the monoguanidine 2-[3-(dimethylamino)propyl]-1,1,3,3-tetramethylguanidine (TMGdmap) and the related bis(guanidine) 1,3-bis( N, N, N′, N′-tetramethylguanidino)propane (btmgp). Low-temperature IR studies in solution support the formation of bis-µ-oxido complexes. For both systems, no intermediates on the pathways to the bis-µ-oxido complexes could be detected; this has been explained through extensive DFT calculations. In the first step, the oxygen reduction during the binding to the copper(I) complex to form a superoxido species was studied. In the second step, the full path from superoxido through trans-µ-peroxido to side- on peroxido and finally bis-µ-oxido was modelled for singlet and triplet states. Hereby, a clear picture of the detailed reaction mechanism, which directly correlates with the observed activation enthalpies and reaction orders, was gained. The superoxido formation is rate-determining as pseudo-first order in copper(I) although the bis-µ-oxido formation is observed. The results illustrate the strength of density functional theory for the prediction of the reactivity of real-life systems. [ABSTRACT FROM AUTHOR]

A combined differential scanning calorimetry (DSC)/X-ray diffraction (XRD) methodology is used to search and identify compounds in the Cu/W/Cl system based on the successive reaction of WCl6 with copper powder. Thermal effects monitored by DSC are used to detect reaction pathways and phase formations of compounds. A series of five new and one already known compounds is discovered as crystalline phases in the Cu/W/Cl system and structurally characterized by XRD. The reaction of WCl6 with elemental copper begins at temperatures as low as 60 °C with the formation of crystalline powders of α-Cu xWCl6. Continuing reaction stages include the successive formation of crystalline phases β-Cu xWCl6, γ-Cu xWCl6, α-Cu2W2Cl10, β-Cu2W2Cl10, and Cu2[W6Cl14]. [ABSTRACT FROM AUTHOR]

The present study provides new experimental data on the reactivity of sulfur-based ligands connected to Re atoms. It was recently discovered that oxidation of µ-S ligands within the bioctahedral [Re12CS14(µ-S)3(CN)6]6- cluster anion using H2O2 led to the formation of µ-SO2 and µ-SO3 products. This work is focused on the investigation of the opposite process - reduction of the [Re12CS14(µ-SO2)3(CN)6]6- anion to [Re12CS14(µ-S)3(CN)6]6- by sulfide ions in an aqueous medium under mild conditions. The reduction results in a slow change of the solution colour, making it possible to investigate in detail the intermediate products. Analysis of the reaction mixture by ESI mass spectrometry revealed that a series of cluster anions [Re12CS17O n(CN)6]6- ( n = 0-5) was generated during the process. This indicates stepwise chemical reduction of bridging SO2 ligands proceeding through the formation of µ-SO ligands. In this way, twelve-nuclear rhenium clusters demonstrate a unique, fully reversible redox cycle of their µ-bridging ligands, keeping the cluster core unchanged. Two mixed-ligand cluster anions, [Re12CS14(µ-SO2)2(µ-S)(CN)6]6- and [Re12CS14(µ-SO2)(µ-S)2(CN)6]6-, were found to be the major reaction intermediates. The former was crystallised with [Cu(NH3)5]2+ and [Cd(NH3) n]2+ ammine cations and investigated by single-crystal X-ray diffraction. To understand the electronic structure and charge distribution in [Re12CS17O n(CN)6]6- cluster anions, DFT calculations were also carried out. [ABSTRACT FROM AUTHOR]

The oxidation of Pd particles and subsequent reduction of PdO were studied in 0.2-0.7 bar O2 and H2 gas at 20-650 °C by in-situ transmission electron microscopy. The 15 nm thick Pd particles were 50-300 nm wide, and (111) oriented on the SiN support. Two oxidation mechanisms were observed: 1) the slow formation of epitaxial PdO at the Pd particle edges with orientations OR(1): PdO[201]//Pd[111] and PdO(020)//Pd{022}, 5.8° from OR(2): PdO[110]//Pd[100] and PdO[001]//Pd[001]. 2) the fast formation of randomly oriented PdO nucleating at the Pd particle edges. During the reduction process we observed epitaxial formation [OR(1) and OR(2)] as well as nonepitaxial formation of Pd (and Pd hydride). The formation of randomly oriented (5-10 nm) Pd particles on a (001) surface of PdO was much slower than of the epitaxial Pd grains on other PdO surfaces. A systematic study of the electron beam irradiation effect on the phase transformations showed that this effect can be avoided. [ABSTRACT FROM AUTHOR]

Noble-metal-derived functional materials have played indispensable roles in the reduction of dye under aqueous conditions; however, their cost and separation are great limitations on their wider practical applications. Therefore, an alternative preparation of comparable materials with low cost and good ease of separation is required. Herein magnetic microspheres (i.e., Fe3O4/Cu) were synthesized through a green single-step solvothermal method for the first time with ethylene glycol serving as reductant and reaction media. The prepared materials were characterized by means of powder Xray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, energy- dispersive X-ray spectrometry, a vibrating sample magnetometer, and so forth. Additionally, by employing the reduction of 4-nitrophenol to 4-aminophenol as a model reaction, the effects of preparation time and the initial dosage of Cu(NO3)2 on the rate constant of the catalytic reduction reaction were systematically investigated. Moreover, the obtained hybrid nanocatalysts were also applied to reduce and degrade common organic dyes (rhodamine B and methylene blue) in the presence of NaBH4. Quite significantly, it was shown that it could catalytically degrade different organic dyes with excellent catalytic performance and high stability in recycled reactions up to five times. More interestingly, the material can be easily separated from the catalytic system for further use. [ABSTRACT FROM AUTHOR]

Novel composite photocatalysts consisting of CdS and graphitic carbon nitride (CdS/g-C3N4) with different ratios of CdS were prepared. The CdS/g-C3N4 composite photocatalysts were characterized in detail and their photocatalytic activity was evaluated by using rhodamine B and colorless metronidazole as probes. Compared with pure g-C3N4, the CdS/ g-C3N4 composite exhibits significantly enhanced photocatalytic activity under visible-light irradiation. More importantly, g-C3N4 substantially reinforces the photostability of CdS nanowires even in a nonsacrificial system. The synergistic effect between CdS and g-C3N4 is found to be primarily responsible for enhancement of the separation of photogenerated electrons and holes, which helps improve the photocatalytic performance. A probable photodegradation process of metronidazole was proposed based on an analysis of the degradation products. This study provides new insight into the preparation of highly efficient and stable sulfidebased composite photocatalysts and facilitates their application in a number of environmentally sensitive areas. [ABSTRACT FROM AUTHOR]

In this paper, we present the first example of a ruthenium(III) complex, [RuIII(edta)] (edta = ethylenediaminetetraacetate), that catalyzes the electrochemical conversion of hydrogen carbonate to formate selectively. The formation of an [RuIII(edta)(HCO3)]2- species through the reaction of the [RuIII(edta)(H2O)]- catalyst and hydrogen carbonate (HCO3-) was studied kinetically by using the stopped-flow technique. The value of the second-order rate constant for the formation of the [RuIII(edta)(HCO3)]2- complex was 82 ± 7 M-1 s-1 at 25 °C and pH = 6.4. Electrochemical reduction of hydrogen carbonate (HCO3-) was achieved by carrying out constant-potential bulk electrolysis at -0.4 V (vs. SCE) with a mercury-pool cathode at pH = 6.4. The formation of formate as the only reduction product was evidenced by a 13C NMR analysis of the reaction mixture obtained after electrolysis. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of 2,5-dihydroxyterephthalic acid (H2dhtp) and magnesium(II) nitrate in N, N-dimethylformamide (DMF) led to the simultaneous formation of two structural isomers, namely, the lvt network Mg(dhtp)(dmf)2 ( 1) and the compound Mg3(dhtp)3(dmf)6 ·0.75H2O ( 2) with the pcu α-Po primitive cubic topology. The same reaction conditions with manganese(II) nitrate and terephthalic acid (H2tp) resulted in the concomitant generation of two drastically different metal-organic frameworks (MOFs), namely, Mn2(tp)2(dmf)2 ( 3) and [Mn(HCOO)3][NC2H8] ( 4), in which the formato ligands and N, N-dimethylammonium cations arise from DMF degradation. [ABSTRACT FROM AUTHOR]

Palladium nanoparticles stabilized by glycodendrimers (PdDSNs) in water were prepared by coordination of PdII to intradendritic triazole ligands upon reaction of K2PdCl4 with the dendrimer in water followed by aqueous NaBH4 reduction to Pd0. TEM images show that the PdDSNs are small (average diameter: 2.3 nm) and relatively monodisperse owing to a low concentration of metal precursor. The catalytic activity of these PdDSNs was evaluated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 (only 0.2 mol-% of Pd per mol substrate is used) and for the Miyaura-Suzuki C-C coupling with various substituted aryl bromides (only 0.01 mol-% of Pd per mol substrate is used). Comparisons of the catalytic activities of these PdDSNs with those of larger PdDSNs (diameter: 14 nm) reveal that smaller NPs catalyze faster 4-NP reduction than their larger counterparts but lack any notable surface dependency for Suzuki-Miyaura catalysis. [ABSTRACT FROM AUTHOR]

The reduction of the compound [Fe2(CO)4(κ2-dmpe){μ-(SCH2)2NBn}] [dmpe = 1,2-bis(dimethylphosphino)ethane], which is considered as an FeI-FeI model of the [2Fe]H subsite of [Fe-Fe]H2ases with a rotated conformation in the solid state, was investigated by cyclic voltammetry. Under reductive conditions, [Fe2(CO)4(κ2-dmpe){μ-(SCH2)2NBn}] undergoes electron-transfer-catalyzed isomerization to afford an isomer featuring a bridging diphosphine [Fe2(CO)4(μ-dmpe){μ-(SCH2)2NBn}]. Comparison of the crystallographic structures of the two isomers affords unique and direct experimental evidence that dissymmetrical coordination of the chelate ligand is required to promote the rotated conformation at one iron atom in this compound. DFT calculations were performed to rationalize this isomerization process and the slightly distorted structure of [Fe2(CO)4(μ-dmpe){μ-(SCH2)2NBn}]. The symmetrization of the coordination sphere results in the disruption of the agostic interaction that stabilized the rotated isomer. [ABSTRACT FROM AUTHOR]

Air-stable gold nanoparticles stabilized by glycodendrimers (AuDSNs) in water were prepared in the presence of a reducing agent, NaBH4. A UV/Vis spectroscopy study demonstrates that no spontaneous reduction of Au3+ ions occurs in the presence of glycodendrimers. The AuDSNs were characterized by UV/Vis spectroscopy and transmission electron microscopy (TEM). TEM images show that the AuDSNs were very small (average diameter: 2.6 nm). The catalytic activity of these AuDSNs was evaluated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 monitored by UV/Vis spectroscopy. Studies of the reduction reaction reveal that the rate constant depends on the concentration of 4-NP. [ABSTRACT FROM AUTHOR]

The kinetics of reduction of the mer-[RuIII(pic)3] complex (pic- = picolinato) by ascorbic acid (AscH2) leading to formation of a red ruthenium(II) species have been studied spectrophotometrically by using both conventional mixing and stopped-flow methods. The reaction was followed as a function of the reductant concentration over a wide pH range (1.0-7.4). Electron transfer proceeds by an outer-sphere mechanism involving three protolytic forms of ascorbic acid, AscH2, AscH- and Asc2-, for which specific rate constants have been determined. The Gibbs' energy of activation was found to correlate linearly with the HOMO energies of the protolytic forms of the reductant. The mer-[RuIII(pic)3] complex is too sparingly soluble in water to inhibit the growth of the Escherichia coli (ATCC 8739) strain. Its cytotoxicity against non-tumorigenic cells precludes its potential use as an anticancer agent. [ABSTRACT FROM AUTHOR]

Recently, it was shown that NiI and CoI complexes with tetraazamacrocyclic ligands [namely, trans-III-NiI L3+ ( L3 = 1,4,8,11-tetraazacyclotetradecane), NiIcyclam and rac-CoI L1+ ( L1 = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene, dien)] reduce maleate ions in aqueous solutions. It was decided to expand the study to further NiIL i+ complexes. In the present study, the reactions of rac-NiI L1+ and meso-NiI L2+ ( L2 = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) with maleate ions were investigated. The effect of the addition of maleic acid to aqueous solutions containing these low-valent metal complexes, prepared by the pulse radiolysis technique, was studied. The d→π* complexes formed between monovalent nickel complexes and maleate ions were detected and characterised by UV/Vis spectroscopy. The nature of the final products formed depends strongly on the nature of the metal and the ligand. Detailed mechanisms of the reduction processes are proposed and compared with those previously reported. The results indicate that the electronic configuration of the central cation as well as the reduction potential of the complex and steric hindrance induced by the ligand affect the reduction mechanism of maleate ions by these analogous complexes. [ABSTRACT FROM AUTHOR]

ZnMn2O4-ZnO-C nanohybrids have been synthesized by means of a simple carbonthermal reduction reaction between ZnMnO3 and acetylene black. ZnMn2O4-C nanohybrids are obtained by further washing with NaOH solution. The reversible discharge capacity of the ZnMn2O4-ZnO-C nanohybrids can reach 620 mA h g-1 at a current density of 100 mA g-1 and 520 mA h g-1 at 800 mA g-1 after 100 cycles. More importantly, ZnMn2O4-C shows better conductivity along with better rate performance after the removal of ZnO. The as-prepared ZnMn2O4-C nanohybrids show a high specific capacity of approximately 750 mA h g-1 at a current density of 100 mA g-1 after 100 cycles and excellent rate performance. The reaction involved in the discharge/charge processes are discussed on the basis of ex situ high-resolution transmission of the electrode materials. The conclusions will be of benefit in the design and exploration of future binary transition-metal oxide anode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

A (β-diketiminato)nickel(II) hydrazido(1-) complex [L tBuNi(η2-N2H3)], { 1, L tBu = [HC(C tBuNC6H3{ iPr}2)2]-} has been obtained by treatment of [L tBuNiBr] with hydrazine. In a reaction of 1 with two equivalents of the azo compound diisopropyl azodicarboxylic ester (adc-O iPr) the Ni(N2H3) entity acts as both a hydrogenating and a reducing agent: diisopropyl hydrazidodicarboxylate (hdc-O iPr) is formed, and more adc-O iPr is reduced by two electrons. The resulting (adc-O iPr)2- is found as a ligand in the ultimate nickel product complex, the trinuclear nickel(II) compound [L tBuNi(μ-adc-O iPr)Ni(μ-adc-O iPr)NiL tBu] ( 2), in which two L tBuNi+ units are linked by a [NiII(adc-O iPr)2]2- moiety. The hypothesis that L tBuNiI species are acting as intermediates was supported by the independent finding that 2 can also be obtained by reaction of [L tBuNi(OEt2)] with adc-O iPr. [ABSTRACT FROM AUTHOR]

Mono-, di- and tetraanions of rubrene, (C42H28, Rub0), were generated by the controlled reduction of neutral polyarene with various alkali metals in the appropriate solvent. The X-ray diffraction studies of the resulting adducts of Rub1-, Rub2- and Rub4- with alkali-metal ions revealed the distortion of the rubrene core upon the stepwise acquisition of electrons. Coordination of the Cs+ ion and a noticeable deformation of Rub1- are observed at the first reduction step. Two types of rubrene dianions showing an essentially different conformation and coordination environment for the central tetracene core have been seen in the cesium adduct of Rub2-. Various types of supramolecular assembly between the tetrareduced rubrene anion, Rub4-, and lithium or rubidium cations have been found in the corresponding products in the solid state. The structures of rubrene anions and their aggregation with alkali-metal ions in solution have been studied by ESR and multinuclear NMR (1H, 13C, 7Li and 133Cs) spectroscopy. [ABSTRACT FROM AUTHOR]

The five-membered electron-transfer series [M(bpy)3] n and [M(tpy)2] n (M = Fe, Ru; bpy = 2,2′-bipyridine, tpy = 2,2′:6′,2″-terpyridine) and [Fe(tbpy)3] n (tbpy = 4,4′-di- tert-butyl-2,2′-bipyridine; n = 3+, 2+, 1+, 0, 1-) have been investigated and the electronic structure of the so called 'low-valent' complexes ( n = 1+, 0, 1-) have been established by a combination of electro- and magnetochemistry, electron paramagnetic resonance (EPR) and Mössbauer spectroscopy, X-ray crystallography, and DFT calculations. These complexes are accessed by reduction of the d6 S = 0 dicationic starting materials [M(bpy)3]2+ and [M(tpy)2]2+ (M = Fe, Ru) and [Fe(tbpy)3]2+. The monocations [M(bpy ·)(bpy0)2]1+ ( S = 1/2) and [M(tpy ·)(tpy0)]1+ ( S = 1/2) (M = FeII, RuII) also contain a low-spin (t2g)6 divalent metal center, plus a single radical monoanion (bpy ·)1- or (tpy ·)1-, and two or one neutral (bpy0) or (tpy0) ligands, respectively. The unpaired electron resides in a ligand π* orbital. The neutral complexes [FeII(bpy ·)2(bpy0)]0 and [RuII(tpy ·)2]0 were found, by DFT calculations, to possess an S = 1 ground state that is attained by weak intramolecular ferromagnetic coupling between two ligand radical anions and a singlet excited state ( S = 0). In contrast, the neutral species [RuII(bpy ·)2(bpy0)]0 possesses an S = 0 ground state. The metal centers of these neutral complexes retain a low-spin (t2g)6 configuration. Remarkably, the corresponding neutral complex [FeII(tpy ·)2]0 contains high-spin FeII ( SFe = 2). Strong intramolecular antiferromagnetic metal-radical coupling yields an experimentally observed S = 1 ground state. The monoanions [MII(bpy ·)3]1- (M = Fe, Ru) are composed of a low-spin metal ion [Fe, Ru; (t2g)6; SM = 0] and three (bpy ·)1- radical anions. [ABSTRACT FROM AUTHOR]

Recent advances in the coordination chemistry of Eu2+ are reviewed. Common synthetic routes for generating discrete Eu2+-containing complexes reported since 2000 are summarized, followed by a description of the reactivity of these complexes and their applications in reduction chemistry, polymerization, luminescence, and as contrast agents for magnetic resonance imaging. Rapid development of the coordination chemistry of Eu2+ has led to an upsurge in the utilization of Eu2+-containing complexes in synthetic chemistry, materials science, and medicine. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue is the group of Peter H.àM. Budzelaar, who recently moved from the University of Manitoba (Winnipeg, Canada) to the University of Naples Federico II (Italy). The cover image shows the very different structures of formally divalent Hf and Zr diiminepyridine complexes. One would expect that most types of "non‐innocent" reactivity have already been discovered, and yet DIPs continue to surprise... Read more about the story behind the cover in the Cover Profile and about the research itself in the Full Paper by P. H. M. Budzelaar et al. [ABSTRACT FROM AUTHOR]

The Front Cover shows the result of the reduction of diiminepyridine Zr and Hf chlorides. Reduction happens at the ligand. Hf goes from seven‐ to five‐coordinate, but the analogous Zr complex forms a six‐coordinate dimer with an unusual coordination geometry. The background shows polar bears iconic of Manitoba, where most of this work was done. More information can be found in the Full Paper by P. H. M. Budzelaar et al. For more on the story behind the cover research, see the Cover Profile. [ABSTRACT FROM AUTHOR]