Elias Drösemeier

Nature Chemistry, Published online: 06 January 2026; doi:10.1038/s41557-025-02026-0

skew-Tetramantane—diamond’s chiral core—previously only accessible from fossil fuels after elaborate separations, was selectively synthesized by a combination of visible-light photocatalytic reactions to modulate radical chemistry and catalyst-controlled C–H insertions. Operating under kinetic control, this stereoselective adamantalogous cage-extension strategy provides access to synthetic diamondoids beyond adamantane, diamantane and triamantane.

A silica-supported Ta/Co heterobimetallic catalyst prepared by surface organometallic chemistry shows excellent room-temperature activity in pentane perdeuteration, outperforming Ta and Ta/Ir systems. By combining the complementary reactivity of the Ta/Co and Ta/Ir catalysts, a mild, solvent-free tandem hydrogen isotope exchange/deuterogenation strategy was further developed for the efficient synthesis of high-purity and high-value THF-d₈.

Abstract

The catalytic hydrogen-isotope exchange (HIE) of unactivated C(sp³)─H bonds remains a formidable challenge, relevant for the synthesis of high-purity high-value perdeuterated NMR solvents such as pentane or tetrahydrofuran. Existing methods primarily rely on precious metal-based catalysts (eg. Ir, Ru) under homogeneous conditions. In pursuit of more sustainable alternatives, we report the synthesis of the heterobimetallic complex [Ta(CH₂ tBu)₂(μ-CHtBu)₂CoCp*], 1, which is used for the preparation of a novel silica-supported tantalum–cobalt heterobimetallic catalyst through Surface OrganoMetallic Chemistry (SOMC). This Ta/Co material demonstrated exceptional catalytic efficiency in perdeuterating pentane under mild conditions (room temperature, < 1 bar D₂, 1 mol% cat.), outperforming both the Ta monometallic and the noble-metal based Ta/Ir heterobimetallic analogues. Furthermore, we took profit of the complementary arene HIE and deuterogenation activities of the Ta/M (M = Ir, Co) catalysts to develop a tandem catalytic synthetic strategy for the efficient preparation of perdeuterated tetrahydrofuran from furan, achieving up to 94% total deuterium incorporation. This novel catalytic system offers several key advantages such as a) mild reaction conditions, b) atom-efficient use of D₂ as the deuterium source, and c) simplified handling, allowing for the recovery of pure deuterated solvent via simple condensation, not hampered by the use of solvents nor additives.

Nature, Published online: 10 December 2025; doi:10.1038/s41586-025-09776-4

Laser-induced conversion electron Mössbauer spectroscopy, which detects electrons emitted by 229Th nuclei in a thin ThO2 sample excited by vacuum ultraviolet light, is demonstrated, opening the possibility of a conversion-electron-based nuclear clock.

The synthesis and characterization of novel mixed group 14/15 metallacycles incorporating a transition-metal is described. All of the presented compounds were obtained by reduction of an organometallic Mo₂E₂ tetrahedrane using Si(I) and Ge(I) compounds, respectively. The size of the obtained metallacycles (three-, four-, five-membered rings) is strongly dependent on the combination of the tetrel as well as the pnictogen atoms.

Abstract

A systematic study on the reactivity of the homodipnictogen tetrahedrane complexes [{Cp‘Mo(CO)₂}₂(μ,η^2:2-E₂)] (E ═ P, As, Sb; Cp‘ = η⁵-C₅H₄ tBu) towards the disilylene [L^PhSi]₂ and digermylene [L^PhGe]₂ (L^Ph = PhC(NtBu)₂) is presented. Depending on the specific combination of tetrel and pnictogen atom, a variety of novel silicon-pnictogen and germanium-pnictogen heterocycles in different bonding situations were obtained. This is a significant development, as these metallacycles are unprecedented and offer new possibilities for further reactivities. These three- to five-membered pure inorganic heterocycles include one Mo, one or two tetrel, and one or two pnictogen atoms in each case. Especially for the heavier pnictogen Sb, this cyclization behavior forming novel three- and four-membered Si–Sb as well as five-membered Ge–Sb ring systems has not been observed so far. These results present unique examples of heavy group 14/15 heterocycles.

The first series of fully characterized homoleptic alkynyl bismuth compounds Bi(C≡CR)₃ is presented. Facile homolytic Bi–C bond cleavage grants access to alkynyl radicals, which have been employed in selective C–X bond formation (X = C, B, Se, Te). This complements existing strategies for alkynyl radical generation as it proceeds under mild and purely thermal conditions, without co-reagents or additives, and in the absence of transition metals.

Abstract

Alkynyl radicals represent highly attractive building blocks in synthetic chemistry but keep posing considerable challenges to researchers in the field. While their existence in interstellar space, in combustion processes, and under matrix-isolation conditions has been documented, access under typical wet-chemical conditions remains limited. In this context, bismuth compounds are promising candidates as their ability to engage in controlled radical reactions has recently been brought into the focus of research efforts. Here, we present the first synthesis and full characterization of a series of homoleptic bismuth alkyne compounds, Bi(C≡CR)₃ (R = alkyl, silyl, aryl). The isolable compounds readily and selectively release alkynyl radicals, as demonstrated by EPR spectroscopic studies. This reactivity has been harnessed in Glaser-type C–C homocoupling reactions, as well as in C–C, C–B, C–Se, and C–Te bond-forming events with external substrates, including transformations that commonly proceed through polar reaction pathways. The bismuth compounds complement existing strategies for the wet-chemical generation of alkynyl radicals in that they are transition-metal-free, avoid toxic components, proceed under mild conditions, can be operated via thermal activation, and do not require any additives or co-reagents.

We report a highly strained boratadisilirane with the elusive anionic BSi₂ ring motif. Cleavage of the Si─Si bond during reactions with pyridine derivatives activates them in three different ways: 1) for pyridine itself selective ortho-CH activation and concomitant hydrogen transfer to a second pyridine molecule occurs, 2) with dimethylaminopyridine, unprecedented C─C bond formation happens between the two DMAP equivalents, and 3) in pentafluoropyridine the para-CF bond is activated under formation of regioisomers.

Abstract

Ring strain is a well-established strategy to increase reactivity. Employing an elusive saturated BSi₂ ring motif, we here exploit the size mismatch between boron and silicon to this end. The reaction of disilenide Tip₂Si = SiTipLi with BH₃·SMe₂ selectively affords the lithium salt of anionic boratadisilirane c-SiTip₂SiHTipBH₂ ⁻ (Tip = 2,4,6-triisopropylphenyl), which according to DFT calculations on the parent system BSi₂H₆ ⁻ is much more strained than isoelectronic analogues such as cyclopropane (C₃H₆), boratirane (BC₂H₆ ⁻), and cyclotrisilane (Si₃H₆). Indeed, it spontaneously and selectively activates a range of pyridine derivatives: pyridine itself undergoes ortho-CH activation under dearomatization of a second equivalent; 2 equivalents of para-dimethylaminopyridine (DMAP) are C─C-coupled in ortho- and meta-position; and pentafluoropyridine (PFP) is CF-activated in para-position.

Fluorido difluoroamido complexes F'MNF₂ of heavy alkaline earth metals (M = Ca, Sr, Ba) were prepared through the reactions of laser-ablated metal atoms with NF₃ and isolated under cryogenic conditions in neon and argon matrices. The species feature a F'−⁻ and a side-on coordinated η³-NF₂ ⁻ ligand with the F'−M−N angle decreasing from calcium to barium.

Abstract

Fluorido difluoroamido complexes F'MNF₂ of heavy alkaline earth metals (M = Ca, Sr, Ba) were prepared through the reactions of laser-ablated metal atoms with diluted NF₃ and isolated in cryogenic neon and argon matrices. They were characterized using Fourier-transform infrared (FTIR) spectroscopy, ^14/15NF₃ isotopic substitution and quantum-chemical calculations. The species feature a F'⁻ and a so far unknown side-on coordinated η³-NF₂ ⁻ ligand with the F'−M−N angle decreasing from Ca to Ba. Bonding analyses suggest that the interactions between the metal center and the ligands are mainly of electrostatic nature. Nevertheless, the orbital interaction shows that an electron donation from the ligands into the empty ns and (n – 1)d orbitals of the metal center further contributes to the electronic structure.

The synthesis of a family of selanyl-stabilized silyl cations is reported. Variations of the scaffold, the substituents at the silicon and the selenium atoms allow to adjust their Lewis acidity over a wide range. The Lewis acidity is quantified by the FBN method.

Abstract

The synthesis of a series of selanyl-stabilized cationic silyl Lewis acids with naphthalene or acenaphthalene scaffolds is described. The influence of scaffold modifications, substitution variations at the selanyl donor and at the silicon atom on the strengths of the silyl Lewis acid is evaluated using the p-fluorobenzonitrile (FBN) method. These simple variations of the principal structure allow to adjust the Lewis acidity of the cationic silyl Lewis acids from weak ones to examples that are significantly stronger than tris(pentafluorophenyl)borane (BCF). The solid-state structure of the cationic FBN complex [11(FBN)]⁺ with an acenaphthene backbone and a pentafluorophenylselanyl donor provides evidence for the penta-coordination of the silicon atom in this complex, in agreement with the results of nuclear magnetic resonance (NMR) studies in solution. Finally, this study suggests that the FBN method is well suited to assess even very subtle differences in the strength of Lewis acids.

The bicyclo[1.1.0]tetragermane-2,4-diide diradicaloid compound [(ADC)₂Ge₄] featuring a stretched bridgehead Ge─Ge bond is reported as a Venetian red crystalline solid. [(ADC)₂Ge₄] has been characterized by experimental and computational methods and its reactivity with TEMPO and Fe₂(CO)₉ has been explored.

Abstract

The synthesis, structure, and reactivity of the bicyclo[1.1.0]tetragermane-2,4-diide compound [(ADC)Ge₂]₂ ( 3 ), which features a Ge₄ core bridged by two anionic dicarbene frameworks (ADC = PhC{N(Dipp)C}₂; Dipp = 2,6-iPr₂C₆H₃), are reported. Treatment of an alkyne-functionalized amidine Me₃SiC≡CN(Dipp)C(Ph)═N(Dipp) ( 1 ) with GeCl₄ affords [(ADC)GeCl₃(GeCl₄)] ( 2 ). KC₈ reduction of 2 yields 3 as a Venetian red crystalline solid. DFT calculations reveal a singlet ground state for 3 with the singlet-triplet energy gap of 14 kcal mol⁻¹. CASSCF (complete active space self-consistent field) calculations suggest a modest diradical character (β = 9%) for 3 . Compound 3 readily reacts with TEMPO (2,2,6,6-tetramethylpiperidinyloxyl) to yield the Ge─Ge bond-cleaved product, [(ADC)Ge(Ge-TEMPO)]₂ ( 4 ). Treatment of 3 with Fe₂(CO)₉ gives [(ADC)Ge(Ge{Fe(CO)₄})]₂ ( 5 ).

Alkyne insertion into the Sn─Si bond of a silyl-substituted stannylene occurs regio-selectively and - in the cases of more sterically encumbered substrates - reversibly

Abstract

A range of aryl- and alkyl- substituted alkynes has been shown to insert regio-selectively into the Sn─Si bond of the electron-rich aryl(silyl)stannylene, Ar^MesSnSi(SiMe₃)₃ (Ar^Mes = 2,6-Mes₂C₆H₃, Mes = 2,4,6-Me₃C₆H₂) to generate a series of vinyl-stannylene products. In all cases, the product features a syn arrangement of Sn and Si-containing groups about the resulting carbon–carbon double bond; in the case of unsymmetrical alkynes, the more sterically bulky group is exclusively incorporated in the 1-position (i.e., proximal to Sn). Remarkably, insertion is shown to occur reversibly in the cases of 3-hexyne and trimethylsilylacetylene. The thermodynamic parameters associated with these processes have been determined by variable temperature NMR spectroscopy, and the activation barriers associated with the key mechanistic steps elucidated by quantum mechanical methods.

Herein, we report the synthesis of a homologous series of ladder cyclohexasilanes containing 1, 2, or 3 fused rings. The tricyclosilanes rank among the most architecturally and stereochemically complex oligosilanes yet synthesized. A combined experimental and theoretical study suggested that the diastereoselectivity in a key annulation is governed by kinetic control. This study also revealed extended σ-conjugation with each additional ring within the all-trans ladder cyclosilanes series.

Abstract

We report the synthesis of five new examples of ladder cyclohexasilanes, possessing up to three consecutive fused rings and differing in relative ring fusion configuration and side chain structure. By coupling a 1,4-dipotassiooligosilyl dianion to a cyclohexasilane, we obtained bi- and tricyclic ladder cyclohexasilanes. Combined experimental and theoretical studies suggested that annulation could favor the cis configuration under kinetic control, while the trans configuration predominates under thermodynamic control. Computational studies show that with each additional ring in the trans-diastereomeric series, the predicted onset of light absorption shifts to longer wavelengths.

We present a surface modification strategy for boosting performance and durability of ITO-free flexible TENG via self-assembled monolayers, yielding record-high power density (27.28 W/m²) and excellent durability upon 5,000 times of bending. Moreover, through optical design for the electrode, our TENG can unprecedentedly exhibit reduced heat gain from solar radiation.

Abstract

Although triboelectric nanogenerators (TENG) have been explored as a promising candidate for applications in multifunctional intelligent systems, the realization of highly efficient TENG that synchronously possess reasonable light transparency, high near-infrared reflectivity against solar heat gain, and good mechanical flexibility still remains challenging. Here, we present a reliable strategy that can substantially boost the performance and durability of indium tin oxide (ITO)-free transparent flexible TENG by surface modification via self-assembled monolayers (SAM). Through the modification of Sb₂O₃/Ag/Sb₂O₃ electrode and polydimethylsiloxane (PDMS) dielectric layer with SAM of 12-(dodecylphosphonic acid) triethyl ammonium bromide and perfluorinated molecules, respectively, triboelectric charge generation is facilitated due to relatively large work function (WF) difference between the tribolayers. The resulting flexible TENG not only afford record-breaking power density (27.28 W/m²) for ITO-free transparent flexible TENG, but also possess high durability against 5,000 cycles of bending owing to good adhesion at the SAM/substrate interfaces and high robustness of electrode. More encouragingly, the use of Sb₂O₃/Ag/Sb₂O₃ electrode endows TENG with both reasonable light transparency and high near-infrared reflectivity, which is beneficial against heat gain from solar radiation. This work showcases a promising route towards realizing transparent flexible TENG with high performance and durability, which represents a new platform for the design of next-generation wearable electronics.

This review highlights recent advances in mechanochemical methods for multistep organic synthesis, focusing on sequential one-pot approaches performed by grinding or ball milling. The presented transformations are discussed in terms of efficiency, applicability, and sustainability, assessing both the challenges and potential of solvent-free one-pot approaches to contribute to greener strategies in organic synthesis.

Abstract

Mechanochemical synthesis has emerged as a powerful and more sustainable alternative to conventional solution-based methods, offering advantages such as no or only minimal solvent use, reduced reaction times, and simplified operational conditions. The integration of multiple steps into a single reaction vessel further enhances these benefits by eliminating workup and purification steps, reducing waste, and often improving overall efficiency. This review highlights recent advancements in mechanochemical one-pot multistep reactions in organic synthesis, focusing on protocols with sequential one-pot operation. Diverse transformations are covered, including heterocycle formation, functional group interconversions, and the synthesis of active pharmaceutical ingredients, while discussing both the operational and environmental advantages of these methodologies, along with their remaining challenges. Overall, mechanochemical one-pot synthesis has the potential to streamline transformations and therefore contribute to more sustainable approaches in modern organic synthetic chemistry.

This study systematically investigates the reactivity of arsine–borane Lewis pairs, which had not been explored previously. Using tertiary arsines with different steric and electronic properties, the formation of classical Lewis adducts, FLP-type encounter complexes, and arsonium borate adducts with B(C₆F₅)₃ was demonstrated. Their reactivity toward small molecules and detailed structural characterization were also reported.

Abstract

Various combinations of Lewis acids and bases, particularly frustrated Lewis pairs (FLPs), have been investigated for their distinctive reactivities. Nevertheless, to date, no systematic study of arsine–borane Lewis pairs has been reported. In this study, tertiary arsines with different degrees of steric hindrance and electron-donating abilities were used. Depending on their steric and electronic properties, arsines form classical Lewis adducts, FLPs, or arsonium borate adducts with tris(pentafluorophenyl)borane (B(C₆F₅)₃). Experimental and computational analyzes revealed that trimesitylarsine and B(C₆F₅)₃ form an encounter complex in solution, which is referred to as an FLP adduct. Furthermore, the arsine–borane pairs react with phenylacetylene and diphenyl disulfide to afford the corresponding arsonium borate adduct and thioarsonium thioborate salt, respectively. The structures of the products were characterized using single-crystal X-ray diffraction.

We report the first example of a bona fide Al=Si double bond stabilized in a four-membered anionic AlSi₃ cycle, which exhibits an unprecedentedly short Al−Si bond length of 2.283(1) Å and a high Wiberg bond index (WBI) of 1.31. We illustrate the typical double bond reactivity through the intramolecular activation of C−H bonds of the Tip group (Tip=2,4,6-triisopropylphenyl), as well as through intermolecular reactions with sulfur sources.

Abstract

Aluminatasilenes are the elusive heavier counterparts of the well-known borataalkenes in which the B=C double bond is formally replaced by an Al=Si moiety. We report the isolation of a four-membered anionic AlSi₃ cycle with a bona fide Al=Si double bond, which is obtained by the reaction of 2 eq. of disilenide Tip₂Si=SiTipLi with H₂AlCl (Tip=2,4,6-triisopropylphenyl). X-ray crystallography, UV/Vis spectroscopy and computational analysis confirm the double bond character with a very short Al−Si bond of 2.283(1) Å and high Wiberg bond index (WBI) of 1.31. Intramolecular C−H activation by the Al=Si bond and the reactions with sulfur sources confirm typical double bond reactivity.