Construction of remote dual stereocenters by electrochemical cobalt-catalyzed enantioselective desymmetrization Yanjun Li, Siyu Liu, Binbin Yuan, Nico Graw, Lutz Ackermann Nature Communications, 2026 The enantio- and diastereoselective construction of two stereogenic centers represents a highly attractive objective in synthetic chemistry. Extensive asymmetric catalytic methods have been developed for the formation of vicinal stereocenters. In contrast, the simultaneous construction of two constitutionally distinct stereogenic centers at remote positions in a single asymmetric catalytic step remains very scarce, owing to the lack of reliable models for distant stereochemical induction for both chiral entities. Herein, we report on an electrochemical cobalt-catalyzed asymmetric hydroacylation of enynes by a desymmetrization strategy that enables the enantio- and diastereo-selective construction of remote dual stereocenters. This unified catalytic platform exhibits broad substrate generality and affords four distinct classes of chiral products, each incorporating two chiral elements: 1,6-central/C–C axial chirality, 1,6-central/C–O axial chirality, 1,5-central/[2.2]paracyclophane planar chirality, and 1,5-central/ferrocene planar chirality.
Intriguing Reactivity of a 1,2-Dihydrodialumane Towards Organic Azides – From a Terminal Diazido–Dialumane to Pendulum-Clock-Like Azide Bridging Xiaobai Wang, Franziska Traeger, Raphael F. Ligorio, Nico Graw, Regine Herbst‐Irmer, et al. Angewandte Chemie International Edition, 2025 The reactivity of dihydro‐dialane with organic azides is described. Treatment of the hybrid ligand‐based dialane [(DNI{H}Al)2] (I) (DNI = [3,3‐dimethyl‐2‐2‐methyl‐2‐(2,6‐diisopropylaniline)ethenyl]‐3H‐indolenine) with TMSN3 (TMS = trimethylsilyl) at room temperature gives the first diazido‐dialane [(DNI{N3}Al)2] (1). The transformation from here to a more stable aluminium‐tetrazole [DNIAl(NTMS)2N2] (2) is established. The reaction of other RN3 gives [(DNI{H}Al)2(κ2‐N3R)] (R = Benzyl in 3 and 1‐Adamantyl in 4) with the azide in a μ‐bridging position between two aluminium atoms. Using 1H NOESY/EXSY NMR spectroscopy, a positional exchange of the two TMS groups (2) via rotation of the tetrazole unit is observed. In contrast, compound 3 exhibits a pendulum‐clock‐like dynamic, with Nα oscillating between the two aluminium atoms in solution. The reaction of dialane I with DippN3 (Dipp = 2,6‐iPr2‐C6H3) gives the dialuminium amine [{DNI(H)Al}2(μ‐NDipp)] (5).
Reducing hybrid ligand-based alane and chasing aluminium(i): dialane and unusual transient dialumene Xiaobai Wang, Raphael F. Ligorio, Franziska Rüttger, David M. J. Krengel, Nico Graw, et al. Dalton Transactions, 2024 The alane [DNIAlH2] (1) was reduced by Jones's Mg(i) and Roesky's Al(i) to give the dialane [{DNI(H)Al}2] (2). 1 with [DippBDIAl:] gives intramolecular C(sp2)–H bond-activated 3. [DNINa] with [(Cp*Al)4] gives C–N activated 5 with an Al2CN ring.
En Route to a Molecular Terminal Tin Oxide Leon Kreßner, Daniel Duvinage, Pim Puylaert, Nico Graw, Regine Herbst-Irmer, et al. Inorganic Chemistry, 2024 In the pursuit of terminal tin chalcogenides, heteroleptic stannylenes bearing terphenyl- and hexamethyldisilazide ligands were reacted with carbodiimides to yield the respective guanidinato complexes. Further supported by quantum chemical calculations, this revealed that the iso-propyl-substituted derivative provides the maximum steric protection achievable. Oxidation with elemental selenium produced monomeric terminal tin selenides with four-coordinate tin centers. In reactions with N2O as oxygen transfer reagent, silyl migration toward putative terminal tin oxide intermediates gave rise to tin complexes with terminal ─OSiMe3 functionality. To prevent silyl migration, the silyl groups were substituted with cyclohexyl moieties. This analogue exhibited distinctively different reactivities toward selenium and N2O, yielding a 1,2,3,4,5-tetraselenastannolane and chalcogenide-bridged dimeric compounds, respectively.
Indium Kα radiation from a MetalJet X-ray source: comparison of the Eiger2 CdTe and Photon III detectors Paul Niklas Ruth, Nico Graw, Tobias Ernemann, Regine Herbst-Irmer, Dietmar Stalke Journal of Applied Crystallography, 2023 The MetalJet source makes available new Kα radiation wavelengths for use in X-ray diffraction experiments. The purpose of this paper is to demonstrate the application of indium Kα radiation in independent-atom model refinement, as well as approaches using aspherical atomic form factors. The results vary greatly depending on the detector employed, as the energy cut-off of the Eiger2 CdTe provides a solution to a unique energy contamination problem of the MetalJet In radiation, which the Photon III detector cannot provide.
Indium Kα radiation from a MetalJet X-ray source: the long way to a successful charge-density investigation Nico Graw, Paul Niklas Ruth, Tobias Ernemann, Regine Herbst-Irmer, Dietmar Stalke Journal of Applied Crystallography, 2023 The MetalJet X-ray source provides indium Kα radiation with a wavelength even shorter than Ag radiation. This paper reports on problematic spectral impurities and presents possible countermeasures so that collection of data with excellent quality up to a high resolution is possible. It is demonstrated that these data can be used in the refinement of a multipole model, the results of which are used for a topological analysis to assess the bonding situation in a sulfur ylide compound.
[2+4] Cycloaddition Product of an Amidinate Substituted Dialumene with Toluene Arun Kumar, Komal Yadav, Nico Graw, Madhusudan K. Pandey, Regine Herbst‐Irmer, et al. Chemistry A European Journal, 2023 Reduction of LAlI2 (L=PhC(NiPr2C6H3)2) with two equivalents of KC8 in toluene affords the [2+4]cycloaddition product of a dialumene with toluene. The mechanism for the formation of product complex was investigated using density functional theory (DFT) methods.
Compounds with Alternating Single and Double Bonds of Antimony and Silicon; Isoelectronic to Ethane-1,2-diimine Mohd Nazish, Christina M. Legendre, Nico Graw, Regine Herbst-Irmer, Shahila Muhammed, et al. Inorganic Chemistry, 2023 We present an approach for preparing chain-type unsaturated molecules with low oxidation state Si(I) and Sb(I) supported by amidinato ligands that exploit to generate heavy analogues of ethane 1,2-diimine. The reduction of antimony dihalide (R-SbCl2) with KC8 in the presence of silylene chloride afforded L─(Cl)Si═Sb─Tip (1) and L(Cl)Si═Sb─TerPh (2), respectively. Compounds 1 and 2 further undergo reduction with KC8 to produce Tip─Sb═LSi─LSi═Sb─Tip (3) and TerPh─Sb═LSi─LSi═Sb─TerPh (4). The solid-state structures and DFT studies show that all compounds have σ-type lone pairs at each Sb atom. It forms a strong pseudo-π-bond with Si. The pseudo-π-bond is formed by the hyperconjugative donation of the π-type lone pair at Sb to the Si-N σ* MO. The quantum mechanical studies indicate that compounds 3 and 4 has delocalized pseudo-π-MOs arising from hyperconjugative interactions. Hence, 1 and 2 can be considered as isoelectronic to imine, while 3 and 4 are isoelectronic to ethane-1,2-diimine. The proton affinity studies indicate that the pseudo-π-bond resulting from the hyperconjugative interaction is more reactive than the σ-type lone pair.
An investigation of Solid-State Emission of Halogenated Diphenyl Phosphanyl Anthracenes Tim Patten, Nico Graw, Sebastian Friedl, Dietmar Stalke, Anna Krawczuk Advanced Optical Materials, 2023 In today's world, the development and research of optoelectronic materials and devices based on solid‐state luminescence is essential. Due to their versatile application possibilities, e.g. as light‐emitting diodes or lasers, they are already indispensable. This work presents three halogenated anthracene derivatives [9‐PPh2‐10‐X‐(C14H8)] and their respective photoluminescent behavior in solution and in the solid state. The formation of halogen–π interactions in the solid state leads to unanticipated luminescence properties for the chlorinated species, resulting in a strong bathochromic shift, green fluorescence and a longer lifetime. In contrast, the other two derivatives, which in turn form only weak π–π interactions due to a small overlap of the anthracene rings, barely change their luminescence behavior in the solid state. By employing additional charge density studies, the structure–property correlation is also investigated. In particular, focus is given to halogen bonding and halogen–π interactions and their influence on photophysical properties of the studied compounds. Through the new knowledge gained, this study will help in the future development and selective application of the photophysical properties of solid‐state luminescent materials.
