1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids

Potent nucleophilicity yet low basicity : A 1,3,2-diazaphospholene (DAP) catalyst in conjunction with PhSiH3 enables the direct conjugate reduction of substituted α,β-unsaturated carboxylic acids without prior deprotonation, highlighting its remarkably potent nucleophilicity and yet low basicity. The transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and tolerates functional groups such as Cbz group or alkyl halides that can be problematic with classical reduction catalysts.

[Communications]

John H. Reed, Prof. Nicolai Cramer

doi.org/10.1002/cctc.202000662

Atomic-Scale Description of Interfaces between Antigen and Aluminum-Based Adjuvants Used in Vaccines by Dynamic Nuclear Polarization (DNP) Enhanced NMR Spectroscopy

Revealing the ties that bind : The nature of molecular interactions at the interface between aluminum-based adjuvants and antigens in vaccine formulations is elucidated by using correlation magic angle spinning dynamic nuclear polarization (MAS DNP) NMR spectroscopy. Data reveal significant differences in these interactions as a function of the adjuvant supplier (see figure).

[Full Papers]

Dr. Jasmine Viger-Gravel, Dr. Federico M. Paruzzo, Dr. Corine Cazaux, Ribal Jabbour, Dr. Amandine Leleu, Dr. Françoise Canini, Dr. Pierre Florian, Dr. Frédéric Ronzon, Dr. David Gajan, Dr. Anne Lesage

doi.org/10.1002/chem.202001141

Increased Lipophilicity of Halogenated Ruthenium(II) Polypyridyl Complexes Leads to Decreased Phototoxicity in vitro when Used as Photosensitizers for Photodynamic Therapy

One up, one down : RuII polypyridyl complexes are prime candidates for the development of new photosensitizers for photodynamic therapy. Increasing their lipophilicity could result in improved pharmacological properties. The relationship between lipophilicity and in vitro phototoxicity of halogenated RuII complexes was investigated.

[Full Papers]

Dr. Saonli Roy, Elisa Colombo, Dr. Robin Vinck, Dr. Cristina Mari, Dr. Riccardo Rubbiani, Dr. Malay Patra, Dr. Gilles Gasser

doi.org/10.1002/cbic.202000289

Reactivity of Diarylnitrenium Ions

Nitrenium conundrum : When exploring synthetic-scale generation of stable diarylnitrenium ions, Ar2N+, we find products quite different to those derived from photochemical generation.

[Communications]

Dr. Agnes Kütt, Prof. Dr. Gunnar Jeschke, Dr. Lauri Toom, Dr. Jaak Nerut, Prof. Christopher A. Reed

doi.org/10.1002/chem.202000930

Evaluation of 5H-Thiazolo[3,2-α]pyrimidin-5-ones as Potential GluN2A PET Tracers

New tools for GluN2A-containing NMDA receptors have been discovered through the optimization of 5H-thiazolo[3,2-α]pyrimidin-5-one derivatives. The radioligand [18F]7b provided high-quality images in autoradiographic studies, while its tritiated analogue [3H2]15b allowed the development of a radioligand binding assay, useful for the study of GluN2A-containing NMDA receptors and the optimization of allosteric modulators binding at the GluN1-GluN2A interface.

[Full Papers]

Yingfang He, Dr. David M. Whitehead, Dr. Emmanuelle Briard, Dr. Shin Numao, Dr. Linjing Mu, Prof. Roger Schibli, Prof. Simon M. Ametamey, Dr. Yves P. Auberson

doi.org/10.1002/cmdc.202000340

Change of Quadrupole Moment upon Excitation and Symmetry Breaking in Multibranched Donor-Acceptor Dyes

The propensity of centrosymmetric multibranched dyes to undergo symmetry breaking was controlled by tuning their change of quadrupole moment upon excitation, ΔQ . This was achieved by varying the length, as well as the strength, of the acceptor arms around the donor core.

[Articles]

Dr. Zoltán Szakács, Dr. Mariusz Tasior, Prof. Daniel T. Gryko, Prof. Eric Vauthey

doi.org/10.1002/cphc.202000253

Hexayne Amphiphiles and Bolaamphiphiles

Surfactants worth the sacrifice : Amphiphilic and bolaamphiphilic functional hexaynes were synthesized using the Egliton-Galbraith reaction and a sacrificial monomer. The novel carbon-rich surfactants form aggregates in water, monolayers on surfaces, and stabilize the liquid-liquid interface.

[Full Papers]

Enzo Bomal, Dr. Vincent Croué, Dr. Reuben Yeo, Dr. Rosario Scopelliti, Prof. Holger Frauenrath

doi.org/10.1002/chem.201904890

Long-Lived Photocharges in Supramolecular Polymers of Low-Band-Gap Chromophores

1D matters ! Low-band-gap chromophores that self-assemble into one-dimensional helical nanowires show light-induced formation of polarons with unusual lifetimes exceeding hours. The accumulation of these charge carriers at concentrations close to that of the metal-insulator transition is reflected by profound macroscopic charge-transport properties and photoconductivity in these confined organic semiconductor systems.

[Full Papers]

Dr. Regina J. Hafner, Dr. Daniel Görl, Dr. Andrzej Sienkiewicz, Dr. Sandor Balog, Prof. Holger Frauenrath

doi.org/10.1002/chem.201904561

Reexamination of the Ergothioneine Biosynthetic Methyltransferase EgtD from Mycobacterium tuberculosis as a Protein Kinase Substrate

Conformer conundrum : The histidine methyltransferase EgtD produces N-α-trimethylhistidine as the first intermediate of ergothioneine biosynthesis in M. tuberculosis . This enzyme can be regulated by kinase-mediated phosphorylation. However, in vitro characterization of this process suggests that folded EgtD is a poor substrate for protein kinase D (PknD).

[Communications]

Alice Maurer, Prof. Dr. Florian P. Seebeck

doi.org/10.1002/cbic.202000232

Solvent-Dependent Growth and Stabilization Mechanisms of Surfactant-Free Colloidal Pt Nanoparticles

Surfactant-free Pt nanoparticles : The careful consideration of the reducing properties of simple solvents like methanol or ethanol are key to control the growth mechanisms, stability and redispersion properties of colloidal surfactant-free Pt nanoparticles. The results provide guidelines to rationally select solvents in surfactant-free syntheses for fundamental and applied research.

[Full Papers]

Dr. Jonathan Quinson, Dr. Sarah Neumann, Laura Kacenauskaite, Dr. Jan Bucher, Prof. Dr. Jacob J. K. Kirkensgaard, Prof. Dr. Søren B. Simonsen, Prof. Dr. Luise Theil Kuhn, Alessandro Zana, Prof. Dr. Tom Vosch, Prof. Dr. Mehtap Oezaslan, Dr. Sebastian Kunz, Prof. Dr. Matthias Arenz

doi.org/10.1002/chem.202001553

Boosting Conjugate Addition to Nitroolefins Using Lithium Tetraorganozincates: Synthetic Strategies and Structural Insights

The metamorphosis of organozinc reagents ! Transforming neutral R2Zn into nucleophilic R4ZnLi2 zincate complexes enabled chemoselective alkylation/arylation of nitroolefins to give 1,4-addition adducts in up to 98 % yield. Structural and spectroscopic investigations confirmed the dianionic-type nature of these species and the key role of donor additives in their aggregation and structure.

[Full Papers]

Dr. Marzia Dell'Aera, Dr. Filippo Maria Perna, Dr. Paola Vitale, Dr. Angela Altomare, Prof. Alessandro Palmieri, Dr. Lewis C. H. Maddock, Leonie J. Bole, Dr. Alan R. Kennedy, Prof. Eva Hevia, Prof. Vito Capriati

doi.org/10.1002/chem.202001294

Boosting Conjugate Addition to Nitroolefins Using Lithium Tetraorganozincates: Synthetic Strategies and Structural Insights

Metamorphosis has always been the greatest symbol of change for everyone ! By transforming dialkylzincs (R2Zn) into tetraorganozincates (R4ZnLi2), a transition metal-catalyst- and ligand-free conjugate addition to nitroolefins becomes feasible en route to valuable nitroalkanes with a broad substrate scope, high chemoselectivity, and functional group tolerance within a 30 min reaction time and with no additional solvents. More information can be found in the Full Paper by E. Hevia, V. Capriati, et al. (DOI: 10.1002/chem.202001521).

[Cover Pictures]

Dr. Marzia Dell'Aera, Dr. Filippo Maria Perna, Dr. Paola Vitale, Dr. Angela Altomare, Prof. Alessandro Palmieri, Dr. Lewis C. H. Maddock, Leonie J. Bole, Dr. Alan R. Kennedy, Prof. Eva Hevia, Prof. Vito Capriati

doi.org/10.1002/chem.202001521

Monohydride-Dichloro Rhodium(III) Complexes with Chiral Diphosphine Ligands as Catalysts for Asymmetric Hydrogenation of Olefinic Substrates

Curious cats : Asymmetric hydrogenation of simple olefins was achieved by using monohydride-dichloro rhodium(III) complexes 1 a -c which were characterized by NMR spectroscopy, including DOSY NMR, and X-ray single crystal analysis. Among these three complexes, 1 c has a rigid pocket surrounded by two chloride atoms bound to the rhodium atom for fitting to simple olefins without any coordinating functional groups.

[Full Papers]

Dr. Kosuke Higashida, Fabian Brüning, Nagataka Tsujimoto, Kenya Higashihara, Dr. Haruki Nagae, Prof. Dr. Antonio Togni, Prof. Dr. Kazushi Mashima

doi.org/10.1002/chem.202000542

Monohydride-Dichloro Rhodium(III) Complexes with Chiral Diphosphine Ligands as Catalysts for Asymmetric Hydrogenation of Olefinic Substrates

Monohydride-dichloro rhodium(III) complexes bearing chiral diphosphine ligands stand as novel candidates for asymmetric hydrogenation of non-functionalized olefins. The sterically hindered chiral diphosphine ligand, (S)-DTBM-SEGPHOS, made it possible to isolate the rhodium(III) complex as a mononuclear complex which was confirmed by XRD analysis and DOSY NMR analysis. The novel monohydride rhodium(III) complex showed much higher enantioselectivity than classical dihydride rhodium systems on asymmetric hydrogenation of non-functionalized olefins. More information can be found in the Full Paper by A. Togni, K. Mashima, et al. (DOI: 10.1002/chem.202000542).

[Cover Pictures]

Dr. Kosuke Higashida, Fabian Brüning, Nagataka Tsujimoto, Kenya Higashihara, Dr. Haruki Nagae, Prof. Dr. Antonio Togni, Prof. Dr. Kazushi Mashima

doi.org/10.1002/chem.202001528

JoyaPhos: An Atropisomeric Teraryl Monophosphine Ligand

JoyaPhos : A new atropisomeric monophosphine (JoyaPhos) was prepared by the sequential de novo introduction of aromatic units, resulting in a configurationally stable teraryl structure with a well-defined topology. The ligand scaffold differs from canonical binaphthyl structures and can accommodate transition metals in a dense ligand sphere, suitable for stereoselective transformations.

[Communications]

Alessandro Castrogiovanni, Dr. Dominik Lotter, Fabian R. Bissegger, Prof. Dr. Christof Sparr

doi.org/10.1002/chem.202001269

Coumarin-Tagged Dinuclear Trithiolato-Bridged Ruthenium(II)⋅Arene Complexes: Photophysical Properties and Antiparasitic Activity

The (para)site for treatment : Thirteen coumarin-diruthenium(II)⋅arene conjugates were evaluated against a transgenic T. gondii strain grown in human foreskin fibroblasts (HFF). The IC50 values ranged from 105 to 735 nM, with nine compounds displaying a lower IC50 than the standard drug pyrimethamine. TEM of T. gondii-infected HFF showed that treatment predominantly affected the parasites’ mitochondrion.

[Full Papers]

Oksana Desiatkina, Emilia Păunescu, Martin Mösching, Nicoleta Anghel, Ghalia Boubaker, Yosra Amdouni, Andrew Hemphill, Dr. Julien Furrer

doi.org/10.1002/cbic.202000174

Generalized Synthesis to Produce Transparent Thin Films of Ternary Metal Oxide Photoelectrodes

Green & versatile : Employing a chelating agent to enable compatible water solubility of diverse metal cations affords a method to fabricate diverse n- and p-type semiconducting metal oxide photoelectrodes. A remarkable improvement in transparency for BiVO4 photoanodes (important for tandem cell operation) is quantified by the direct transmittance at 600 nm of >80 % versus the <10 % observed with the state-of-the-art material.

[Full Papers]

Dr. Charles R. Lhermitte, Annalisa Polo, Dr. Liang Yao, Dr. Florent A. Boudoire, Dr. Nestor Guijarro, Prof. Dr. Kevin Sivula

doi.org/10.1002/cssc.202000926

Selective Conversion of Various Monosaccharaides into Sugar Acids by Additive-Free Dehydrogenation in Water

Catalysis in water : A sustainable catalytic process for the conversion of sugars into sugar acids using water as solvent without additives.

[Full Papers]

Andres Mollar-Cuni, Dr. Joseph P. Byrne, Dr. Pilar Borja, Dr. Cristian Vicent, Prof. Martin Albrecht, Dr. Jose A. Mata

doi.org/10.1002/cctc.202000544

Light-Harvesting Supramolecular Polymers: Energy Transfer to Various Polyaromatic Acceptors

Supramolecular polymers formed from phosphodiester-bridged phenanthrene trimers are doped with charged and uncharged acceptor chromophores. Excitation of the phenanthrenes is followed by efficient energy transfer to the acceptor molecules.

[Communications]

Jovana Jevric, Dr. Simon M. Langenegger, Dr. Robert Häner

doi.org/10.1002/ejoc.202000441

Synthesis and Biological Evaluation of Endocannabinoid Uptake Inhibitors Derived from WOBE437

To elucidate the key structural features underlying the specific inhibitory activity of WOBE437, we conducted a comprehensive SAR study on almost 80 WOBE437 analogues. Several variants exhibited potencies in the sub-100 nM range and were highly selective over inhibition of the endocannabinoid-degrading fatty acid amide hydrolase. However, none of the analogues surpassed the potency of WOBE437.

[Full Papers]

Dr. Patrick Mäder, Dr. Ruben Bartholomäus, Dr. Simon Nicolussi, Alice Baumann, Melanie Weis, Dr. Andrea Chicca, Dr. Mark Rau, Dr. Ana Catarina Simão, Prof. Dr. Jürg Gertsch, Prof. Dr. Karl-Heinz Altmann

doi.org/10.1002/cmdc.202000153

The Quest for Xenobiotic Enzymes: From New Enzymes for Chemistry to a Novel Chemistry of Life

Unlimited : Current research on artificial enzymes conclusively shows that we are not limited to nature's biocatalytic repertoire. Functional xenobiology, that is, the implementation of new-to-nature reactions in vivo, will open up a plethora of novel applications and has the potential for transformative biotechnological innovation. Herein, we highlight current challenges and future opportunities for xenobiotic reactions in living cells.

[Minireviews]

Tobias Vornholt, Dr. Markus Jeschek

doi.org/10.1002/cbic.202000121

Two-Stage Polyelectrolyte Assembly Orchestrated by a Clock Reaction

Around the clock : A cationic polyelectrolyte is assembled with temporal control by means of the formaldehyde-sulfite clock reaction. Electrostatic interactions template microscopic complexes, which are then crosslinked covalently to lock-in a preformed structure. The final particle size can be controlled simply by tuning either the concentrations of components, or the initial pH value.

[Full Papers]

Christian C M. Sproncken, Dr. Berta Gumí-Audenis, Dr. Guido Panzarasa, Prof. Dr. Ilja K. Voets

doi.org/10.1002/syst.202000005

Surface Display of Complex Enzymes by in Situ SpyCatcher-SpyTag Interaction

Room for independent folding . A surface display method employs the SpyCatcher-SpyTag system for post-translational in situ coupling of independently expressed and properly folded passenger enzymes and membrane anchors. The efficient surface display of delicate and complex enzymes expands the toolbox for the fabrication of productive whole-cell biocatalysts.

[Communications]

Sabrina Gallus, Dr. Theo Peschke, Dr. Malte Paulsen, Dr. Teresa Burgahn, Prof. Christof M. Niemeyer, Dr. Kersten S. Rabe

doi.org/10.1002/cbic.202000102

Mechanistic Study of Diaryl Ether Bond Cleavage during Palladium-Catalyzed Lignin Hydrogenolysis

The road less traveled : Palladium-catalyzed hydrogenolysis of 4-O-5 diaryl ether lignin model compounds gives unexpected rearrangement monomer products. A mechanistic study indicates the cleavage of the diaryl ether bonds in lignin does not undergo a conventional solvolysis pathway but a Pd-coordinated pathway. The bond cleavage is affected by the presence of phenolic groups in the lignin.

[Full Papers]

Dr. Yanding Li, Dr. Steven D. Karlen, Dr. Benginur Demir, Dr. Hoon Kim, Prof. Jeremy Luterbacher, Prof. James A. Dumesic, Prof. Shannon S. Stahl, Prof. John Ralph

doi.org/10.1002/cssc.202000753

Photochemistry Relaunched

[Meet the Board]

Prof. Dr. Christian G. Bochet

doi.org/10.1002/cptc.202000052

Bifunctional DNA Duplexes Permit Efficient Incorporation of pH Probes into Liposomes

Fluorescent pH-sensitive probes have been trapped in the lumen of liposomes. The sensor is linked to a DNA oligomer that is complementary to a second oligomer with a lipophilic moiety to anchor the DNA conjugate to the inner and outer leaflets of the lipid bilayer. The DNA scaffold allows subsequent selective removal of the probe in the outer bilayer leaflet.

[Full Papers]

Nicolas Dolder, Prof. Dr. Christoph von Ballmoos

doi.org/10.1002/cbic.202000146