A Knowledge-Based Molecular Single-Source Precursor Approach to Nickel Chalcogenide Precatalysts for Electrocatalytic Water, Alcohol, and Aldehyde Oxidations.

The development and comprehensive understanding of nickel chalcogenides are critical since they constitute a class of efficient electro(pre)catalysts for the oxygen evolution reaction (OER) and value-added organic oxidations. This study introduces a knowledge-based facile approach to analogous NiE (E = S, Se, Te) phases, originating from molecular β-diketiminato [NiE] complexes and their application for OER and organic oxidations. The recorded activity trends for both target reactions follow the order NiSe > NiS > NiTe.

Disilicon-Mediated Carbon Monoxide Activation: From a 1,2,3-Trisila- to 1,3-Disilacyclopentadienes with Hypercoordinate λSi-λC Double Bonds.

The facile reaction of the SiPh-bridged bis-silylene (LSi:)SiPh (L=PhC(NBu)) with diphenylacetylene affords the unprecedented 1,2,3-trisilacyclopentadiene (LSi)(PhC)SiPh 1 with a hypercoordinate λSi-λSi double bond. Compound 1 is very oxophilic and consumes three molar equivalents of inert NO to form the bicyclic oxygenation product 2 through O-atom insertion in the Si=Si and Si-Si bonds. Strikingly, 1 can completely split the C≡O bonds of carbon monoxide under ambient conditions (1 atm, room temperature), yielding the 1,3-disilacyclopentadiene 3, representing the first hypercoordinate example of a cyclosilene with a λSi-λC double bond.

Bis-Silylene-Supported Aluminium Atoms with Aluminylene and Alane Character.

The suitability of electron-rich bis-silylenes, specifically the neutral chelating [Si(Xant)Si] ligand (Si=PhC(NBu)Si, Xant=9,9-dimethylxanthene) and the anionic [Si(N)Si)] pincer ligand (N=2,7,9,9-tetramethylacridane), has been successfully probed to stabilize monovalent bis-silylene-supported aluminium complexes (aluminylenes). At first, the unprecedented aluminium(III) iodide precursors [Si(Xant)Si]AlI I 1 and [Si(N)Si)]AlI 2 were synthesized using AlI and [Si(Xant)Si] or [Si(N)Si)]Li(OEt)], respectively, and structurally characterized. While reduction of 1 with KC led merely to unidentified products, the dehalogenation of 2 afforded the dimer of the desired {[Si(N)Si)]Al:} aluminylene with a four-membered Si Al ring.

Silylene-Stabilized Neutral Dibora-Aromatics with a B═B Bond.

The unprecedented silylene-supported dibenzodiboraoxepin and 9,10-diboraphenanthrene complexes and were synthesized. The (NHSi)B(xanthene) [NHSi = PhC(NtBu)(MeN)Si:] results from debromination of the bis(NHSi)-stabilized bis(dibromoboryl)xanthene with potassium graphite (KC); is capable of activating white phosphorus and ammonia to form the BP cage compound and HN-B-B-H diborane species , respectively. The thermal rearrangement of affords the 9,10-dihydro-9,10-diboraphenanthrene through a bis(NHSi)-assisted intramolecular reductive C-O-C deoxygenation process.

Stabilizing Monoatomic Two-Coordinate Bismuth(I) and Bismuth(II) Using a Redox Noninnocent Bis(germylene) Ligand.

The formation of isolable monatomic Bi complexes and Bi radical species is challenging due to the pronounced reducing nature of metallic bismuth. Here, we report a convenient strategy to tame Bi and Bi atoms by taking advantage of the redox noninnocent character of a new chelating bis(germylene) ligand. The remarkably stable novel Bi cation complex , supported by the new bis(iminophosphonamido-germylene)xanthene ligand [(P)Ge(Xant)Ge(P)] , [(P)Ge(Xant)Ge(P) = PhP(NBu)Ge(Xant)Ge(NBu)PPh, Xant = 9,9-dimethyl-xanthene-4,5-diyl], was synthesized by a two-electron reduction of the cationic BiI precursor complex with cobaltocene (CpCo) in a molar ratio of 1:2.

Intermetallic Cobalt Indium Nanoparticles as Oxygen Evolution Reaction Precatalyst: A Non-Leaching p-Block Element.

Merely all transition-metal-based materials reconstruct into similar oxyhydroxides during the electrocatalytic oxygen evolution reaction (OER), severely limiting the options for a tailored OER catalyst design. In such reconstructions, initial constituent p-block elements take a sacrificial role and leach into the electrolyte as oxyanions, thereby losing the ability to tune the catalyst's properties systematically. From a thermodynamic point of view, indium is expected to behave differently and should remain in the solid phase under alkaline OER conditions.

Plasma-Mediated Manganese Oxide Electrocatalysts for Quasi-Industrial Water Oxidation and Selective Dehydrogenation.

The production of renewable feedstocks through the coupled oxygen evolution reaction (OER) with selective organic oxidation requires a perfect balance in the choice of a catalyst and its synthesis access, morphology, and catalytic activity. Herein we report a rapid plasma approach to produce a hierarchical amorphous birnessite-type manganese oxide layer on 3D nickel foam. The as-prepared anode exhibits an OER activity with overpotentials of 220, 250, and 270 mV for 100, 500, and 1000 mA·cm, respectively, and can spontaneously be paired with chemoselective dehydrogenation of benzylamine under both ambient and industrial (6 M KOH, 65 °C) alkaline conditions.

A Facile Molecular Approach to Amorphous Nickel Pnictides and Their Reconstruction to Crystalline Potassium-Intercalated γ-NiOOH Enabling High-Performance Electrocatalytic Water Oxidation and Selective Oxidation of 5-Hydroxymethylfurfural.

The low-temperature molecular precursor approach can be beneficial to conventional solid-state methods, which require high temperatures and lead to relatively large crystalline particles. Herein, a novel, single-step, room-temperature preparation of amorphous nickel pnictide (NiE; EP, As) nanomaterials is reported, starting from NaOCE(dioxane) and NiBr (thf) . During application for the oxygen evolution reaction (OER), the pnictide anions leach, and both materials fully reconstruct into nickel(III/IV) oxide phases (similar to γ-NiOOH) comprising edge-sharing (NiO ) layers with intercalated potassium ions and a d-spacing of 7.

Robert C. West (1928-2022): A Giant in Organosilicon Chemistry, Cosmopolitan, Mountain Climber and Pilot.

Robert (Bob) Culbertson West passed away on October 12, 2022. Along with his pioneering contributions in the field of organosilicon chemistry, he will be remembered as an outstanding researcher who brought together many extraordinary talents and interests in addition to science.

Degradation of Phenol via an Advanced Oxidation Process (AOP) with Immobilized Commercial Titanium Dioxide (TiO) Photocatalysts.

Four commercial titanium dioxide (TiO) photocatalysts, namely P25, P90, PC105, and PC500, were immobilized onto steel plates using a sol-gel binder and investigated for phenol degradation under 365 nm UV-LED irradiation. High-performance liquid chromatography (HPLC) and total organic carbon (TOC) analyses were performed to study the impact of three types of oxygen sources (air, dispersed synthetic air, and hydrogen peroxide) on the photocatalytic performance. The photocatalyst films were stable and there were significant differences in their performance.

Synthesis and Reactivity of an Anti-van't Hoff/Le Bel Compound with a Planar Tetracoordinate Silicon(II) Atom.

For a long time, planar tetracoordinate carbon (ptC) represented an exotic coordination mode in organic and organometallic chemistry, but it is now a useful synthetic building block. In contrast, realization of planar tetracoordinate silicon (ptSi), a heavier analogue of ptC, is still challenging. Herein we report the successful synthesis and unusual reactivity of the first ptSi species of divalent silicon present in , supported by the chelating bis(-heterocyclic silylene)bipyridine ligand, 2,2'-{[(4-BuPh)C(NBu)]SiNMe}(CN), ].

Chelating Bis-silylenes As Powerful Ligands To Enable Unusual Low-Valent Main-Group Element Functions.

ConspectusSilylenes are divalent silicon species with an unoccupied 3p orbital and one lone pair of electrons at the Si center. Owing to the excellent σ-donating ability of amidinato-based silylenes, which stems from the intramolecular imino- donor interaction with the vacant 3p orbital of the silicon atom, N-heterocyclic amidinato bis(silylenes) [bis(NHSi)s] can serve as versatile strong donating ligands for cooperative stabilization of central atoms in unusually low oxidation states. Herein, we present our recent achievement on the application of bis(NHSi) ligands with electronically and spatially different spacers to main-group chemistry, which has allowed the isolation of a variety of low-valent compounds consisting of monatomic zero-valent group 14 E complexes (named "metallylones", E = Si, Ge, Sn, Pb); monovalent group 15 E complexes (E = N, P, isoelectronic with metallylones); and diatomic low-valent E complexes (E = Si, Ge, P) with intriguing electronic structures and chemical reactivities.

Evolution of Carbonate-Intercalated γ-NiOOH from a Molecularly Derived Nickel Sulfide (Pre)Catalyst for Efficient Water and Selective Organic Oxidation.

The development of a competent (pre)catalyst for the oxygen evolution reaction (OER) to produce green hydrogen is critical for a carbon-neutral economy. In this aspect, the low-temperature, single-source precursor (SSP) method allows the formation of highly efficient OER electrocatalysts, with better control over their structural and electronic properties. Herein, a transition metal (TM) based chalcogenide material, nickel sulfide (NiS), is prepared from a novel molecular complex [Ni (PyHS) ][OTf] (1) and utilized as a (pre)catalyst for OER.

Spectroscopic Properties of a Biologically Relevant [Fe (μ-O) ] Diamond Core Motif with a Short Iron-Iron Distance.

Diiron cofactors in enzymes perform diverse challenging transformations. The structures of high valent intermediates (Q in methane monooxygenase and X in ribonucleotide reductase) are debated since Fe-Fe distances of 2.5-3.

Reviving Oxygen Evolution Electrocatalysis of Bulk La-Ni Intermetallics via Gaseous Hydrogen Engineering.

A hydrogen processing strategy is developed to enable bulk LaNi to attain high activity and long-term stability toward the electrocatalytic oxygen evolution reaction (OER). By a combination of in situ Raman and quasi in situ X-ray absorption (XAS) spectra, secondary-electron-excited scanning transmission electron microscopy (STEM) patterns as well as the Rietveld method and density functional theory (DFT) calculations, it is discovered that hydrogen-induced lattice distortion, grain refinement, and particle cracks dictate the effective reconstruction of the LaNi surface into a porous hetero-nanoarchitecture composed of uniformly confined active γ-NiOOH nanocrystals by La(OH) layer in the alkaline OER process. This significantly optimizes the charge transfer, structural integrity, active-site exposure, and adsorption energy toward the reaction intermediates.

Oxygen Evolution Activity of Amorphous Cobalt Oxyhydroxides: Interconnecting Precatalyst Reconstruction, Long-Range Order, Buffer-Binding, Morphology, Mass Transport, and Operation Temperature.

Nanocrystalline or amorphous cobalt oxyhydroxides (CoCat) are promising electrocatalysts for the oxygen evolution reaction (OER). While having the same short-range order, CoCat phases possess different electrocatalytic properties. This phenomenon is not conclusively understood, as multiple interdependent parameters affect the OER activity simultaneously.

A bis(silylene)pyridine pincer ligand can stabilize mononuclear manganese(0) complexes: facile access to isolable analogues of the elusive d-Mn(CO) radical.

Using the potentially tridentate ,-bis(-heterocyclic silylene)pyridine [SiNSi] pincer-type ligand, 2,6-,-diethyl-bis[,-di--butyl(phenylamidinato)silylene] diaminopyridine, led to the first isolable bis(silylene)pyridine-stabilized manganese(0) complex, {κ-[SiNSi]Mn(dmpe)} 4 (dmpe = (MeP)CH), which represents an isolobal 17 VE analogue of the elusive Mn(CO) radical. The compound is accessible through the reductive dehalogenation of the corresponding dihalido (SiNSi)Mn(ii) complexes 1 (Cl) and 2 (Br) with potassium graphite. Exposing 4 towards the stronger π-acceptor ligands CO and 2,6-dimethylphenyl isocyanide afforded the related Mn(0) complexes κ-[SiNSi]Mn(CO) (5) and κ-[SiNSi]Mn(CNXylyl)(κ-dmpe) (6), respectively.

An Isolable 2,5-Disila-3,4-Diphosphapyrrole and a Conjugated Si=P-Si=P-Si=N Chain Through Degradation of White Phosphorus with a N,N-Bis(Silylenyl)Aniline.

White phosphorus (P ) undergoes degradation to P moieties if exposed to the new N,N-bis(silylenyl)aniline PhNSi 1 (Si=Si[N(tBu)] CPh), furnishing the first isolable 2,5-disila-3,4-diphosphapyrrole 2 and the two novel functionalized Si=P doubly bonded compounds 3 and 4. The pathways for the transformation of the non-aromatic 2,5-disila-3,4-diphosphapyrrole PhNSi P 2 into 3 and 4 could be uncovered. It became evident that 2 reacts readily with both reactants P and 1 to afford either the polycyclic Si=P-containing product [PhNSi P ] P 3 or the unprecedented conjugated Si=P-Si=P-Si=NPh chain-containing compound 4, depending on the employed molar ratio of 1 and P as well as the reaction conditions.

The Heaviest Bottleable Metallylone: Synthesis of a Monatomic, Zero-Valent Lead Complex ("Plumbylone").

The elusive plumbylone {[Si (Xant)Si ]Pb } 3 stabilized by the bis(silylene)xanthene chelating ligand 1, [Si (Xant)Si =PhC(NtBu) Si(Xant)Si(NtBu) CPh], and its isolable carbonyl iron complex {[Si (Xant)Si ]Pb Fe(CO) } 4 are reported. The compounds 3 and 4 were obtained stepwise via reduction of the lead(II) dibromide complex {[Si (Xant)Si ]PbBr } 2, prepared from the bis(silylene)xanthene 1 and PbBr , employing potassium naphthalenide and K Fe(CO) , respectively. While the genuine plumbylone 3 is rather labile even at -60 °C, its Pb →Fe(CO) complex 4 turned out to be relatively stable and bottleable.

Synthesis of High Surface Area-Group 13-Metal Oxides via Atomic Layer Deposition on Mesoporous Silica.

The atomic layer deposition of gallium and indium oxide was investigated on mesoporous silica powder and compared to the related aluminum oxide process. The respective oxide (GaO, InO) was deposited using sequential dosing of trimethylgallium or trimethylindium and water at 150 °C. In-situ thermogravimetry provided direct insight into the growth rates and deposition behavior.

Unexpected White Phosphorus (P ) Activation Modes with Silylene-Substituted o-Carboranes and Access to an Isolable 1,3-Diphospha-2,4-disilabutadiene.

New types of metal-free white phosphorus (P ) activation are reported. While the phosphine-silylene-substituted dicarborane 1, CB-SiP (CB=ortho-C,C'-C B H , Si=PhC(tBuN) Si, P=P[N(tBu)CH ] ), activates white phosphorus in a 2 : 1 molar ratio to yield the P -chain containing species 2, the analogous bis(silylene)-substituted compound 3, CB-Si reacts with P in the molar ratio of 2 : 1 to furnish the first isolable 1,3-diphospha-2,4-disilabutadiene (Si=P-Si=P-containing) compound 4. For the latter reaction, two intermediates having a CB-Si P and CB-Si P core could be observed by multinuclear NMR spectroscopy.

The Pivotal Role of s-, p-, and f-Block Metals in Water Electrolysis: Status Quo and Perspectives.

Transition metals, in particular noble metals, are the most common species in metal-mediated water electrolysis because they serve as highly active catalytic sites. In many cases, the presence of nontransition metals, that is, s-, p-, and f-block metals with high natural abundance in the earth-crust in the catalytic material is indispensable to boost efficiency and durability in water electrolysis. This is why alkali metals, alkaline-earth metals, rare-earth metals, lean metals, and metalloids receive growing interest in this research area.

A Genuine Stannylone with a Monoatomic Two-Coordinate Tin(0) Atom Supported by a Bis(silylene) Ligand.

The monoatomic zero-valent tin complex (stannylone) {[Si (Xant)Si ]Sn } 5 stabilized by a bis(silylene)xanthene ligand, [Si (Xant)Si =PhC(NtBu) Si(Xant)Si(NtBu) CPh], and its bis-tetracarbonyliron complex {[Si (Xant)Si ]Sn [Fe(CO) ] } 4 are reported. The stannylone 5 bearing a two-coordinate zero-valent tin atom is synthesized by reduction of the precursor 4 with potassium graphite. Compound 4 results from the Sn halide precursor {[Si (Xant)Si ]Sn Cl}Cl 2 or {[Si (Xant)Si ]SnBr } 3 through reductive salt-metathesis reaction with K Fe(CO) .

Deoxygenation of Nitrous Oxide and Nitro Compounds Using Bis(N-Heterocyclic Silylene)Amido Iron Complexes as Catalysts.

Herein, we report the efficient degradation of N O with a well-defined bis(silylene)amido iron complex as catalyst. The deoxygenation of N O using the iron silanone complex 4 as a catalyst and pinacolborane (HBpin) as a sacrificial reagent proceeds smoothly at 50 °C to form N , H , and (pinB) O. Mechanistic studies suggest that the iron-silicon cooperativity is the key to this catalytic transformation, which involves N O activation, H atom transfer, H release and oxygenation of the boron sites.

A Striking Mode of Activation of Carbon Disulfide with a Cooperative Bis(silylene).

The reactivity of the 1,4-substituted bis(silylenyl)terphenylene 1, 1,4-[ortho-(LSi)C H ] C H , (L=RC(NtBu) , R=Ph, Mes) towards CS is reported. It results in a dearomatization of the phenylene ring, affording the 1,3-substituted cyclohexadiene derivative 2. According to DFT calculations, a transient silene containing a Si=C bond capable of π(C=C) addition at the aromatic phenylene ring is a key intermediate.